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CHAPTER – 4 CURVES & TURNOUTS ********************* PART ‘A’ - CURVES SECTION – I: GENERAL 401 Determination of Radius:- (1) The rad...
CHAPTER – 4 CURVES & TURNOUTS ********************* PART ‘A’ - CURVES SECTION – I: GENERAL 401 Determination of Radius:- (1) The radius of a curve is determined by measuring the versine on a chord of known length, from the equation, 125 × 𝐶 2 𝑅= 𝑉 Where; R = Radius in metres; C = Chord length in metres; and V = Versine in millimetres. (2) Curves can be designated by the radius in metres or by its degree. The angle subtended at the centre by a chord of 30.5 metres, is the degree of the curve. 360 30.5 1° curve is thus of = 1750 metres radius 2 2° curve has a radius of 1750 = 875 metres and so on. 2 (3) Curves shall be described by the radius in metres. (4) For measuring versines of a curve, 20 metres overlapping chords should normally be used with stations at 10 metres intervals. For checking the radii of turnout and turn-in curves overlapping chord of 6 metres should be used and the versine measuring stations should be located at every 3 metres. (The turnout curve can also be checked by offsets from the straight). (5) The versine is obtained by stretching a fishing/ nylon cord or wire stretched between the end of chord length decided upon, and the measuring distance between the cord/wire and gauge face of the rail at the middle point of the chord. Care should be taken that the cord or wire is applied to the side of the head of the rail at the gauge point. 402 The Reference Rail for Level:- The level of inner rail of any curve is taken as reference level. The super-elevation is provided by raising the outer rail. For reverse curves, however, stipulation as laid down in Para 406(3) shall apply. 403 Safe Speed on Curves:- (Back to Para 409) (1) Fully transitioned curves – The maximum permissible speed for transitioned curves should be determined (based on the assumption that the centre-to-centre distance between railheads is 1750 mm) using the following formulae: V = 0.27 R (Ca + Cd ) Where, V = Speed in Kmph. R = Radius in metres. Ca = Actual cant in mm. Cd = Permissible cant deficiency in mm. Page 152 of 417 (2) Non transitioned curves with cant on virtual transition – (Back to Para 405) The determination of the maximum permissible speed on curves without transition involves the concept of the virtual transition. The change in the motion of a vehicle from straight to curve conditions takes place over the distance between the bogie centres, commencing on the straight at half the distance before the tangent point and terminating on the curve at the same half distance beyond the tangent point. Normally, the length of virtual transition is taken as 14.785 m over which Super- elevation is gained with maximum permissible cant gradient as per Para 405. (3) For curves laid with inadequate length of transition or without transition, the safe permissible speed should be worked out on the basis of actual cant/cant deficiency, which can be provided taking into consideration the limiting values of cant/cant deficiency gradient and the rate of change of cant and cant deficiency. (4) The speed as determined above shall not exceed the maximum permissible speed of the section. 404 Super-elevation, Cant Deficiency and Cant Excess:- (1) Super-elevation/cant – (a) The equilibrium super elevation/cant necessary for any speed is calculated from the formula. 𝐺 × 𝑉2 𝐶= 127 × 𝑅 Where, C is cant /Super-elevation in mm, G is the dynamic gauge (nominal gauge of track + width of railhead) in mm; R is the radius of the curve in metres. (b) The equilibrium speed for determination of cant to be provided shall be decided by the Chief Engineer, after taking into consideration the maximum speeds which can be actually attained by fast and slow trains, the proximity of permanent speed restriction in the route, junctions, stopping places, gradients which may reduce the speeds of goods trains, without appreciably affecting the speed of fast trains and their relative importance. For this purpose, the entire section may be divided into certain number of sub sections with a nominated equilibrium speed for each sub section, fixed on the basis of speeds which can be actually attained by fast or slow trains over the sub section, so that the need for imposing any speed restrictions for limiting the cant excess for slow trains and cant deficiency for fast trains is avoided. On sections where all trains run at about the same maximum permissible speeds like suburban section, it will be preferable to provide cant for that speed. (c) The amount of Super-elevation to be actually provided will be calculated by the formula given in Sub-Para (a) for the equilibrium speed determined on the basis of Sub-Para (b) above. The calculated cant shall be rounded off in the multiple of 5 mm. (d) Maximum cant on curved track shall be as under – (Back to Para 405) (i) Broad Gauge – Group ‘A’, ‘B’ and ‘C’ routes-165 mm. Note – Maximum cant of 185 mm may be assumed for the purpose of locating all permanent structures etc., by the side of the curves on new constructions and doubling on group ‘A’ routes having potential for increasing the speed in future. The transition length should also be provided on the basis of 185 mm cant for the purpose of planning and layout of the curve. Page 153 of 417 (ii) Broad gauge – Group ‘D’ and ‘E’ routes-140 mm. (e) In every case, the Super-elevation to be provided should be specified when the line is originally laid and thereafter altered only with the prior approval of the Chief Engineer. (2) Cant Deficiency – Maximum value of cant deficiency: (a) On routes with sectional speed more than 100 Kmph for nominated rolling stock with permission of Principal Chief Engineer 100 mm (b) For Broad Gauge routes not covered by above 75 mm (3) Cant Excess-The cant excess should not be allowed to exceed 75 mm for all types of rolling stock. The cant excess should be worked out taking into consideration the booked speed of goods trains on a particular section. In the case of a section carrying predominantly goods traffic, the cant excess should be preferably kept low to minimize wear on inner rail. 405 Length of Transition Curve and Setting-out Transitions:- (Back to Para 403, 410, 419) (1) The desirable length of transition ‘L’ shall be maximum of the following three values – (a) L= 0.008 Ca × Vm (b) L= 0.008 Cd × Vm (c) L= 0.72 × Ca Where, L = the length of transition in metres. Vm= max. permissible speed in Kmph. Cd= cant deficiency in mm. Ca= actual Super-elevation on curve in mm. The formula (a) and (b) are based on rate of change of cant and of cant deficiency of 35 mm per second. The formula (c) is based on the maximum cant gradient of 1 in 720 or 1.4 mm per metre. The length of transition so calculated should be rounded off to the next higher value in multiple of 10 m. (2) For the purpose of designing future layouts of curve, future higher speeds (such as 160 Kmph for Group ‘A’ routes and 130 Kmph for Group ‘B’ routes) may be taken into account for calculating the length of transitions. The provision given in Para 404 (1) (d) may also be considered while deciding the transition length. (3) In exceptional cases where room is not available for providing sufficiently long transitions in accordance with the above, the length may be reduced to a minimum of 2/3 of the desirable length as worked out on the basis of formula (a) and (b) above or ½ of the desirable length as worked out on the basis of (c) above whichever is greater. This is based on the assumption that a rate of change of cant/cant deficiency will not exceed 55 mm per second and the maximum cant gradient will be limited to 2.8 mm per metre or 1 in 360. (4) At locations where length of transition curve is restricted, and therefore, may be inadequate to permit the same maximum speed as calculated for the circular curve, it will be necessary to select a lower cant and/or a lower cant deficiency which will reduce the maximum speed on the circular curve but will increase the maximum speed on the transition curve. In such cases, the cant should be so selected as to permit the highest speed on the curve as a whole. (5) In case of doubling and New lines, if a curve is not possible to be designed for 160 Kmph for Group ‘A’ and 130 Kmph for Group ‘B’ routes, approval of PCE shall be obtained. Page 154 of 417 An example is illustrated with calculations below – A curve of 600 metres radius has a limited transition of 40 metres length, the calculation of maximum permissible speed and super-elevation is as follows – Speed on transition curve = Speed on circular curve Rate of change of cant × L × 3.6 = 0.27 R (C a + C d ) Ca (3.6 is a factor used for converting m/sec to Kmph) Best values of speed are obtained when Ca = Cd Adopting the same units and the maximum value of rate of change of cant of 55 mm per second for Broad Gauge – 55 X 40 X 3.6 Ca = 0.27 600 2Ca Solving Ca = 89.50 or 90 mm Limiting the value of Cd to 75 mm Maximum speed = 0.27 R (C a + C d ) = 0.27 × √600 × (90 + 75) = 84.95 say 85 Kmph Cant gradient = (90/40000) = 1/444, which is within the permissible limits The rate of change of cant at 85 Kmph works out to 53.12 mm/second, which is also within the permissible limits. (6) Laying Transition – (a) A transition curve is laid out as a cubic Parabola and to accommodate this, the main circular arc is moved inwards by an amount called the “Shift”. The “Shift” is calculated from the formula: L2 S= 24R Where, S = shift in metres L & R being in metres. (b) The offset in metres from the straight to any point on the transition curve is calculated from the formula – X3 Y= 6 RL Where, Y= offset from the straight in metres. X= distance from the commencement of the curve in metres, and L & R length of transition and radius of curve respectively in metres. Page 155 of 417 (c) The arrangement of a transition curve is shown in the figure below – The original circular curve TC is tangential to the straight at T. The curve is shifted to ZY and TZ is the amount of shift. The transition curve MNP bisects the shift TZ at N. (7) When realigning old curves, transition curves on approaches should invariably be provided wherever feasible. It should be ensured that there is no change of grade over the transition. (8) Compound Curves – In case of a compound curve, which is formed, by two circular curves of different radii but curving in the same direction, common transition curve may be provided between the circular curves. Assuming that such compound curve is to be traversed at uniform speed, the length of the common transition connecting the two circular curves can be obtained from – (a) L = 0.008 (Ca1- Ca2) x Vm (b) L = 0.008 (Cd1-Cd2) x Vm Whichever, is greater. Where, Ca1 and Cd1 are cant and cant deficiency for curve No.1 in mm; Ca2 and Cd2 are cant and cant deficiency for curve No.2 in mm; L is length of common transition in metres; and Vm is max. permissible speed in Kmph. The Cant gradient should be within the permissible limits as stated in Sub Para (1) & (3) above. Common transition may be provided when the length of common transition as worked out above is more than the length of virtual transition as specified in Para 403 (2). (9) Reverse Curves – (a) In case of a reverse curve, which is formed by two circular curves in opposite directions, common transition curve may be provided between circular curves. The total length of common transition, i.e., from first circular curve to second circular curve, may be obtained from – (i) L = 0.008 (Ca1+Ca2) x Vm (ii) L = 0.008 (Cd1+Cd2) x Vm Whichever is greater; Where, Ca1 and Cd1 are cant and cant deficiency for curve No.1 in mm; Ca2 and Cd2 are cant and cant deficiency for curve No.2 in mm; L is length of transition in metres; and Vm is max. permissible speed in Kmph. Cant gradient should be within the permissible limits as stated in sub Para (1) & (3) above. Page 156 of 417 (b) For high speeds, in Group ‘A’ and ‘B’ routes, a straight with a minimum length of 50 m shall be kept between two transitions of reverse curves. (i) On groups ‘A’ and ‘B’ routes on straights less than 50 metres between reverse curves should be eliminated by suitably extending the transition lengths. In doing so, it should be ensured that the rate of change of cant and versine along the two transitions so extended is kept the same. (ii) Whenever such straights between reverse curves can neither be eliminated nor the straight length increased to over 50 metres, speed in excess of 130 Kmph should not be permitted. 406 Running out Super-elevation:- (Back to Para 402) (1) On transitioned curves, cant should be run up or run out on the transition, not on the straight or on the circular curve, increasing or decreasing uniformly throughout its length. (2) On non-transitioned curves, cant should be run up or run out on the ‘virtual transition’. (3) Longitudinal profile of transition on the reverse curve may be from one of the following two alternatives- (a) In case I, the level of one of the rails is maintained and the super elevation is run out on the other rail by lowering it over half the transition length and raising it to the required amount of cant over the remaining half portion of the transition. (b) In case II, the level of the centre line of the track is maintained the same throughout, and the cant is provided by raising one rail by half the amount of cant and lowering the other rail by the equal amount. Cant is run out or gained over the length of the transition by raising and lowering both the rails by equal amount symmetrically, with respect to the level of the centre line track. In case I, the level of the centre of the track gets disturbed whereas in case II, it is maintained the same throughout. VERSINE OR CANT DIAGRAM RAIL 1 CENTRE LINE OF THE TRACK RAIL 2 CASE: I LONGITUDINAL CASE: II PROFILE (4) Special cases of Super-elevation run out may be approved by the Chief Track Engineer. 407 Indicators/Boards Provided in Curves:- (1) Curve Board – Each approach of a curve should be provided with a curve board at the tangent point fixed on the outside of the curve. This Board should indicate the radius of the curve, the length of the curve, length of transition in metres and the maximum cant provided on the circular portion of curve in millimetres. (2) Rail Posts Indicating Tangent Points – On the inside of the curve, rail posts should be erected on each approach of the curve, to indicate the positions of the beginning and Page 157 of 417 end of transition curves. These rail posts may be painted in red and white colours respectively. In the case of non-transitioned curve, similar rail post should be erected on the tangent track and on the circular curve over which the cant is run out, indicating the beginning and end of the virtual transition. (3) Indication of cant on track – Super-elevation or cant should be indicated by painting its value on the inside face of the web of the inner rail of the curve and at every versine station, beginning with zero at the commencement of the transition curve. The value of cant should be indicated on the circular curve at its beginning and at the end. In the case of long circular curve, the cant value should be indicated at intermediate stations at a distant not exceeding 250 metres. (4) When curves are realigned, the repositioning of the curve boards and posts and repainting of values of Super-elevation at intermediate points should be done, as required. 408 Speed over Turnout on Curves:- (Back to Para 426) (1) Provision in General Rules – Relevant Para 4.10 of “General Rules, 1976 Edition” is reproduced below – (a) The speed of trains over non-interlocked facing points shall not exceed 15 Kmph in any circumstances and the speed over turnout and crossovers shall not exceed 15 Kmph, unless otherwise prescribed by approved special instruction, which may permit a higher speed. (b) Subject to provision of sub-rule (a) above, a train may run over interlocked facing points at such speed as may be permitted by the standard of interlocking. (2) Turnouts on Running Lines with Passenger Traffic – (Back to Para 408) (a) Turnouts in running lines over which passenger trains are received or dispatched should be laid with 1 in 12 curved switch or flatter. (b) 1 in 8.5 turn out with curved switches can be laid in exceptional circumstances taking off from straight track with the approval of PCE. (c) Emergency crossovers between double or multiple straight lines, which are laid only in the trailing direction, may be permitted to be laid with 1 in 8½ crossings (d) For snag dead end, 1 in 8½ symmetrical split turnouts may be used. (e) The turnouts have inbuilt curvature as a part of the design. Therefore, it is desirable that laying of turnouts should normally be avoided on curved main line from the consideration of maintainability & comfort. If the laying of turnout on curved main line is inevitable due to site constraints, following stipulations shall be followed: (i) for laying of turnouts with 1 in 12 or flatter crossings taking off from curve, it shall be ensured that the resultant lead curve radius as well as the radius of main line curve shall not be less than 350m. (ii) 1 in 8.5 turnout shall not be laid from inside of a curved track (iii) 1 in 8½ turnout with curved switches may be laid from outside of a curve up to five degree in exceptional circumstances with the approval of PCE, where due to limitation of room it is not possible to provide 1 in 12 turnout. Note: The existing turnouts not conforming to the stipulations given in Sub-Para (e) above may continue. However, efforts shall be made to eliminate such layouts in a planned manner. (f) Radius of turn-in-curve should generally be not less than 350 metre however, where it is not practicable to achieve the radius of curvature of turn-in curves as 350 m on account of existing track centres for the turnout taking off from curves, the turn-in curves may be allowed upto a minimum radius of 220 m subject to the Page 158 of 417 following – (i) such turn-in curves are provided on PSC sleepers only, with sleeper spacing same as that for the main line. (ii) full ballast profile, same as that for the main line, is provided. (3) Speed over interlocked turnouts – (a) Speed in excess of 15 Kmph may be permitted for straights of interlocked turnouts only under approved special instructions in terms of Para 4.10 of “General Rules, 1976 Edition”. (b) In the case of 1 in 8½, 1 in 12 and flatter turnouts provided with curved switches, higher speeds as permitted under approved special instructions may be allowed on the turn- out side, provided the turn-in curve is of a standard suitable for such higher speeds. While permitting speed beyond 15 Kmph, provisions of Para 408 (4) below may be kept in view. (c) The permissible speed on turnouts taking off on the inside of the curve should be determined by taking into consideration the resultant radius of lead curve which will be sharper than the lead curve for turn-outs taking off from the straight. (4) Up-gradation of Speeds on Turnouts and Loops to 30 Kmph- (a) Length of Section – Up-gradation of speeds on turnout should cover a number of contiguous stations at a time so as to derive a perceptible advantage of the higher speed in train operation. The works described below should cover all the running loops on the stretch of line taken up. (i) Turnouts – Speed, in excess of 15 Kmph, should be permitted on turnouts laid on PSC sleepers only. All turnouts on the running loops shall be laid with curved switches, with minimum rail section being 52 kg/m. All rail joints on these turnouts should also be welded to the extent possible. For different type of curved switches permissible speed are as under – Sl. No. Type of Turnout Permissible speed 1. 1 in 8½ curved switch 15 Kmph 2. 1 in 8½ symmetrical split with curved switches 30 Kmph 3. 1 in 12 curved switch 30 Kmph Note: The permissible speed for 1 in 12 TWS is 50 Kmph (ii) Track on Running Loops – The minimum track structure on the running loops should be 52 Kg/m rails laid as Short Welded Panels, sleeper density 1540 Nos. per km and 150 mm clean ballast cushion. Proper drainage of the area should also be ensured. (iii) Turn-in curves – Turn-in curves should be laid with the same rail section as on the turnout with PSC sleepers with sleeper spacing being 65 cm centre to centre (maximum). Turn-in curve should conform to Para 408(2) and especially so in respect of curvature of the lead curve. Extra shoulder ballast of 150 mm should be provided on outside of the turn-in curve. The frequency of inspection of turn-in curves should be same as that for main line turnouts. 409 Permissible Speed over Curved Main Line at Turnouts: - Subject to the permissible run through speed governed by the interlocking standard, speed over the main line will be determined taking into consideration the maximum cant that can be provided on the main line and the permissible amount of cant deficiency. Page 159 of 417 (1) In the case of turnout of similar flexure, the maximum cant that can be provided, on the main line will be the sum of equilibrium cant for the turnout and permissible cant excess. (2) In the case of turnouts of contrary flexure, the maximum cant on the main line (negative Super-elevation on turnout) will be the difference between the maximum permissible cant deficiency and cant determined for turnout from the formula given in Schedule of Dimensions as indicated in Para 411 below. (3) In both the cases, the permissible speed on the main line will be worked out by the formula as given in Para 403(1). 410 No Change of Super-elevation over Turnouts:-There should be no change of cant between points 20 metres outside the toe of the switch and the nose of the crossing except in cases where points and crossings have to be taken off from the transitioned portion of a curve. Normally, turnouts should not be taken off the transitioned portion of a main line curve. However, in exceptional cases, when such a course is unavoidable a specific relaxation may be given by the Chief Track Engineer of the Railway. In such cases, change of cant and/or curvature may be permitted at the rates specified in Para 405 or such lesser rates as may be prescribed. 411 Curves of Contrary Flexure: - (Back to Para 429) On the main line curve from which a curve of contrary flexure takes off, the cant of the main line (which is the negative Super-elevation on the turnout), should be calculated from the formula given in the Schedule of Dimension and the permissible speed on the main line determined from the allowable cant deficiency and cant on the main line. The speed so determined shall be subject to limitations governed by the standard of interlocking and the sectional speed. 412 Curves of Similar Flexure:- (Back to Para 429) (1) Not followed by reverse curves – On a main line curve from which a curve of similar flexure takes off, not followed immediately by a reverse curve, the turnout curve shall have the same cant as the main line curve. (2) Followed by reverse curves – A change of cant on the turnout may be permitted starting behind the crossing (after the last exit sleeper) and being run out at a rate not steeper than 2.8 mm per metre and subject to the maximum cant on the main line turnout being limited to 65 mm. The permissible speed on the main line is then determined from the allowable cant- deficiency and subject to limitations governed by the standard of interlocking and the safe speed limit. 413 Curves with Cross Overs: - On curves on double line connected by cross over road, the speed and the cant for both roads are governed by the inner road to which the cross over road is a curve of contrary flexure. On the outer road, it is a curve of similar flexure. The permissible speed and the necessary cant on the inner road shall be calculated in accordance with Para 411 above. The same speed and the same cant shall be allowed on the outer road. The outer track shall be raised so that both roads lie in the same inclined plane in order to avoid change in cross level on the cross over road. Where this is not possible, both main line and the turnout should be laid without cant and suitable speed restriction imposed. 414 Curves with Diamond Crossing: - Normally straight diamond crossings should not be provided in curves as these produce kinks in the curve and uniform curvature cannot be obtained. Page 160 of 417 However, where provision of such diamonds cannot be avoided or in case where such diamonds already exists in the track, the approach curves of these diamonds should be laid without cant for a distance of at least 20 metres on either side of the diamond crossings. The cant should be uniformly run-out at the rate specified in Para 405 beyond 20 metres. The speed restrictions on the approach curve shall be decided in each case by the Chief Track Engineer taking into consideration the curvature, cant deficiency and lack of transition but shall in no case be more than 65 Kmph. In the case of diamond crossings on a straight track located in the approach of a curve, a straight length of minimum 50 m between the curve and the heel of acute crossing of diamond is necessary for permitting unrestricted speed over the diamond, subject to maximum permissible speed over the curve from considerations of cant deficiency, transition length etc. 415 Extra Clearance on Curves: - On curves, additional lateral clearances, in excess of the fixed dimensions should be provided as laid down in the Schedule of Dimensions – (1) Between adjacent tracks and (2) Between curved track and fixed structure. 416 Compensation for Curvature on Gradient: - Compensation for curvature should be given in all cases where the existing gradient when added to the curve compensation exceeds the ruling gradient. The compensation to be allowed should ordinarily be (70/R) %. (i.e., 0.04% per degree of curvature), where R is the radius of curvature in metres. Thus, for a ruling gradient of 0.5% or 1 in 200, the gradient for 583 metre radius of curvature should be flattened to 0.5% - {(70/583)or(3° x 0.04 %)} = 0.38% or 1 in 264. 417 Vertical Curve: - (Back to Para 657) A vertical curve shall be provided only at the junction of the grade when the algebraic difference between the grades is equal to or more than 4 mm per metre or 0.4%. The minimum radius of the vertical curve shall be kept as under: Group A Group B Group C, D & E 4000 metres 3000 metres 2500 metres Page 161 of 417 SECTION – II: RE-ALIGNMENT OF CURVES 418 Running on Curves:- (1) For smooth and satisfactory running on curves – (a) There should be no abrupt alteration of curvature and/or Super-elevation (cant), and (b) The Super-elevation should be appropriate to the curvature, at each point. (2) The versines, Super-elevation and gauge should be checked by the JE/SSE/P.Way(Sectional), SSE/P.Way(In-charge) and ADEN as per prescribed schedule for inspection and also whenever the running over curves is found to be unsatisfactory as a result of inspection by locomotive or by carriage or as a result of Track Recording. (3) The results of the inspections shall be recorded as per the proforma given in Annexure - 4/1 and necessary entries made in TMS. (4) Based on the results of the inspections the decision to realign should be taken by the SSE/P.Way in-charge or Assistant Divisional Engineer. (5) The criteria for realignment of a Curve, based on service limit for station to station versine variation, shall be as per Para 524. 419 String lining Operations:- (1) The work of realigning and transitioning curves consists of the following three main operations – (a) Survey of the existing curve by measurement of versines. (b) Determination of the revised alignment and computation of slews, including provision of correct Super-elevation. (c) Slewing of the curve to the revised alignment. (2) Operation No. 1 – Versine survey of curve – (a) Versine readings shall be taken along the gauge face of the outer rail. (b) To ensure inclusion of the point of commencement of the curve, a mark is made on the gauge face of the outer rail at a distance of at-least 30 m (three stations) behind the beginning of curve, and at the end of curve as indicated by station markings on the rails. i.e., station number zero/last station (or apparent tangent point, if no such markings exist on track). (c) If station markings at every 10 m interval are not available on track, it shall be marked at every 10 m (half-chord distance) interval beginning from the marking made before beginning of the curve (vide Sub-Para (b) above) till the marking beyond end of the curve (vide Sub-Para (b) above), (d) These “stations” should be marked and numbered in white paint on the rail. (e) With a fishing cord or wire stretched out over the full length of the cord, the versines are measured to 1 mm accuracy serially at each station from one end of the curve to the other with the rule held normal to the line and recorded. (f) Certain features, which restricts slewing of the track either inwards or outwards should also be recorded, indicating the maximum extent inwards or outwards to which slewing is possible- (i) under existing circumstances; and (ii) if a moderate expenditure could be incurred in removing the “restriction”. (g) The existing Super-elevation should also be measured and recorded against each “Station”. Page 162 of 417 (h) The record obtained would be in the following form: Curve from km............................to km............………………................ Between station..................................…and station...................................... Date of survey............................................................................................... Jurisdiction of JE/SSE/P.Way (In-Charge) / (Sectional) ……………………….. Station Versine (mm) Cant Existing Remarks regarding No restrictions to Slewing 0 0 Zero 1 2 5 mm 2 4 10 mm 3 4 20 mm 4 10 25 mm 5 11 28 mm 1.6 metres 6 23 25 mm G B obligatory point 7 30 28 mm High Bank, Moorum etc (i) In the case of reverse curves, the versine survey should be continuous, but transferred to the outer rail at points where the curvature changes sign. It is probable that the exact point will not be definite; it is therefore, desirable to keep the original rail face as the base until the change is certain to enable plus or minus versines to be read from the same rail, it is only necessary to hold the fishing cord or wire 20 mm clear of the rail edge at each end by using special gadget and subtracting 20 mm from the reading at the centre. (j) Where there are two or more lines, track centres should also be recorded at every station. After the versine-survey, the curve alignment shall not be disturbed until the realignment is commenced. (3) Operation No. 2 – Determination of revised alignment and computation of slews – (a) The basic principles of string lining are as follows – (i) the chord length being identical, the sum total of the existing versines should be equal to the sum total of the proposed versines. (ii) the slew in any direction at a station affects the versine values at the adjacent stations by half the amount in the opposite direction, when the track is not disturbed at the adjacent stations. (iii) the second summation of versine difference between proposed versine and existing versine represents half the slew at any station. (iv) at the first and at the last station, the slews should be zero. (b) The calculations for obtaining a realignment solution are carried out in the following manner (Refer Table-1); (i) after recording the versines in mm, proposed versines are selected in such a way as to obtain uniform rate of change of versines over the transition curve; and uniform versines over the circular portion of the curves. (ii) the difference between the proposed and the existing versines are worked out for each station, the positive sign being used, if the proposed versine is greater than the existing versine and negative sign if it is less (Ref. Col. 4 -Table 1), at the end of this Sub-Para (4), wherein a solution to a realignment of curve is worked out. (iii) first and second summations of the differences of proposed and existing versines are then worked out (Ref. Col. 5 & 6). (iv) the first summation at any station, gives the cumulative versine difference at each station. To begin with this value for station ‘0’ is the same as the versine difference (Col. 4). Page 163 of 417 To obtain the corresponding value for station No. 1 the cumulative versine difference of station ‘0’ (Col. 5) is added to the versine difference of station No. 1 (Col. 4) diagonally downward as shown by the arrow indication and the resultant value is written against Station No. 1 (Col. 5). Similarly, the cumulative versine difference is calculated at each station till the last station is reached. Since the sum total of the existing and the proposed versines is the same, the figure against the last station will be ‘0’ (Col. 5). (v) the second summation at any station gives the cumulative effect of the figures of first summations upto the previous station. It can be proved theoretically that this represents half the slew required at each station to obtain the proposed versine. To start with, this value for station no. ‘0’ is taken as zero. To obtain the corresponding value of Station No.1, the second summation value of the station ‘0’ (i.e., the previous station) is added to the first summation value of the same station ‘0’, as shown by horizontal arrow. This value is shown against Station No. 1 (Col. 6). Similarly, the second summation for Station No. 2 is the sum of the figures of the first summation and second summation of Station No. 1 (Col. 5 and 6). The second summation is obtained against each station till the last station is reached. The slew at the last station should be zero. Otherwise, the track beyond the last station will be affected by the slew at the last station. Normally this figure at the last station may not be zero. To make it zero correcting couples are applied. (vi) Method of applying correcting couples – For correcting the half throws to zero the procedure shall be as follows – When the final half-throw is negative, add to the versines having the lower station numbers and subtract an equal amount from the versines having the higher station numbers, selecting “station” in pairs such that the sum of the products of the difference of the “station” numbers taken in pairs and the amount added to the versines, equals the numerical amount of the negative half-throw to be cleared. When the final half-throw is positive, subtract from the versines having the lower station numbers and add an equal amount to the versines having the higher station numbers, selecting the stations in pairs such that the sum of the product of differences of the station numbers in pairs and the amount subtracted from the versines, equals the numerical amount of the positive half throw to be cleared. (c) For computing slews when realigning and/or transitioning a complete curve the following procedure should be adopted – (i) calculate the length of transition from Para 405. This determines the versine gradient on the transition. (ii) work out versine difference, first and second summations as discussed above at the initial stations with a view to foreseeing and exercising due control over the slews (col. 4, 5 and 6). (iii) review the figures of proposed versines (col 3), if necessary and continue the process until the transition at the other end on which the specific versine gradient should be observed. (iv) in the process, it must be ensured that difference of versines (col. 4) should sum up to zero. (v) apply correcting couples to control the slew at obligatory points and to close the slew at the end to zero. (vi) the slews must be limited to the minimum possible. Page 164 of 417 (vii) determine correct cant to be provided, points of zero and maximum cant and the cant run-off. (viii) alternatively, suitable computer softwares, where available may be used to determine the final values of slew. (d) Maximum Slew – Maximum slew at any station is usually limited by practical considerations. The distance between tracks and adequate clearance to existing structures must be maintained and track must not be slewed too near the edge of the formation. At certain locations like bridges, it may not be possible to slew the curve at all. (e) In carrying out the calculations for the realignment of a long curve of more than 50 stations, it is best to write down values of about 10 proposed versines at a time and see that the sum is approximately the same as that of the corresponding old versines and then workout the second summation to ensure that slews are minimum. A final adjustment to ensure that the sum of the existing and proposed versines is equal and that the slew at last station is zero can then be made. (f) For obtaining a suitable re-alignment solution, the proposed versines should be selected carefully. (g) A numerical example is given in Table 1, which will illustrate the method of working out the solution for realignment of a curve. (4) Operation No. 3 – Slewing the curve to revised alignment – (a) The revised alignment of the curve should be staked out with a steel tape by using the pegs cut from the bars (or wooden stakes with tack marks). These are fixed on the cess on the inner side of the curve square to the track and at such a distance according to the value of the slews, so that the final alignment of the track is at one gauge distance from the face of the pegs (or the tacks on wooden pegs) to the outer edges of the inner rail. (b) In narrow cuttings with sharp curves or in tunnels it may not be possible to measure versines on the pegs driven on the inner cess of the curve due to the face of the cutting fouling the fishing cord. In such cases, the pegs may be driven on the outer cess. The correctness of the peg locations should be checked, by measuring the versines on these pegs and, verifying that they correspond to the final versines (of the re-alignment solution). (c) In no case should these be fixed on formation that is not firm or at locations where they are liable to the disturbed or tampered with. (d) The curve should then be correctly slewed with reference to the pegs. (e) Along with slewing of the curve to the revised alignment correct Super-elevation should be provided at each station to accord with the curvature, particular attention being paid to the run-off on the transition. Repositioning of posts on the cess to indicate zero and maximum Super-elevation and remarking of cant values on the inside web of the inner rail should be done. 420 Realigning Curves on Double or Multiple Lines:-On double or multiple tracks, each curve should be string-lined independently. No attempt should be made to realign any curve by slewing it to a uniform centre to centre distance from the realigned curve as – (1) The existing track centres may not be uniform and relatively small slew on one may entail a much larger (even prohibitively large) slew on the adjacent track. (2) The transitions at the entry and exit may be of different lengths, which make it impracticable to maintain uniform track centres on them even though the degree of the circular curves may be nearly the same. 421 Cutting of Rails on Curves:- (Back to Para 715) Rails are usually laid with square fish plated joints on curve. On curved track the inner rail fish plated joints gradually lead over the outer rail joints. When the inner rail of the curve is ahead of the outer rail by an amount equal to half the pitch of boltholes, cut rails should be Page 165 of 417 provided to obtain square joints. Cut rail is a rail, which is shorter than the standard length of rail by an amount equal to the pitch of the boltholes. The excess length ‘d’ by which the inner rail gains over the outer rail is calculated by the formula – LG d = where, R ‘d’ is the length in mm by which the inner rail joint is ahead of the outer rail joint over the entire length of the curve, if cut rails are not provided. L = length of the curve in metre R = radius of the curve in metre G = the gauge + width of the rail head in mm 422 Joints on Curves:- (Back to Para 715) (1) It must be ensured that fish plated rail joints are square at beginning and at the end of the curve. (2) On the sharp curves less than 400 metres the rail joints may be staggered, where elbows/kinks are likely to develop if rail joints are laid square. 423 Check Rails on Curves:- Check rail reduces the risk of derailment on the sharp curves. (1) Check rail should be provided on the inside of the inner rail of the curve, with appropriate clearances between the checkrail and the running rail, as stipulated in the “Schedule of Dimensions”. (2) Locations where checkrail should be provided shall be decided by the Divisional Engineer taking into consideration the negotiability of the rolling stock and the curve geometry. 424 Wear on Outer Rail of Curves:- (Back to Para 613) (1) The wear on the outer rail on the curve can be reduced effectively by- (a) Lubricating the gauge face of outer rails on the curves. (b) Maintaining correct curve geometry and Super-elevation. (c) Provision of suitable checkrail. (d) Adopting slack gauge PSC sleeper as per RDSO drawings depending on curvature of track. (2) Track mounted automatic Gauge Face Lubricators should be provided on curves of radius 875 m (2°) and sharper to reduce rail gauge face wear. On routes where rail grinding is in practice, track mounted automatic Gauge Face lubricators should be provided on curves of radius 1400 m (1.25°) and sharper. Lubrication should be done on new rails or on old rails, which do not have Gauge Corner Cracking or head checks. While deciding the location of lubricators, following should be considered:- (a) It is located on tangent track at the beginning of transition curve where wheel flanging is just beginning to occur. (b) On single lines, the lubricator shall be located in the direction of heaviest traffic. (c) Lubricators should be located away from switches, crossings and other areas where discontinuity in LWR track may exist. 425 Measurement of Rail Wear on Sharp Curves: -The wear of rails of curves having radius of 600 m or less shall be recorded periodically as specified by the zonal railway. The lateral wear, vertical wear and total loss of section should be recorded and proper record of measurements maintained. Page 166 of 417 Page 167 of 417 Annexure - 4/1 (Para 418) Page 168 of 417 PART – ‘B’ POINTS & CROSSINGS 426 (1) Turnout:-It is a geometrical installation of track to allow movement of train from one track to another track. The turnout consists of following sub-assemblies: (a) Switch assembly (b) Lead assembly (c) Crossing assembly (2)Turn in Curve: The curve connecting the turnout curve after heel of crossing and the adjoining track is called turn in curve. (Refer Para 408) Turn in Curve Page 169 of 417 427 Assembly drawings:-The turnout and its sub-assembly drawings numbers commonly being utilized on Indian Railways are as under: RDSO Drawing No. Sl. Switch Crossing Rail Section and sleeper Angle of Crossing Complete No. sub sub Layout Assembly Assembly 1 52 Kg/m Rail on PSC sleeper 1 in 8½ RT-4865 RT-4866 RT-4867 2 60 Kg/m Rail on PSC sleeper 1 in 8½ RT-4965 RT-4966 RT-4967 3 52 Kg/m Rail on PSC sleeper 1 in 12 RT-4732 RT-4733 RT-4734 4 60 Kg/m Rail on PSC sleeper 1 in 12 RT-4218 RT-4219 RT-4220 5 60 Kg/m Rail on PSC sleeper 1 in 16 RT-5961 RT-5962 RT-5963 6 60 Kg/m Rail on PSC sleeper 1 in 20 RT-5858 RT-5859 RT-5860 60 Kg/m Rail on PSC sleeper Thick 7 1 in 8½ RT-6279 RT-6280 RT-4967 web Switch with Zu – 1 – 60 rails) 52 Kg/m Rail on PSC sleeper Thick 8 1 in 12 RT-5268 RT-5269 RT-4734 web Switch with Zu – 2 – 49 rails) 60 Kg/m Rail on PSC sleeper Thick 9 1 in 12 RT-6154 RT-6155 RT-4220 web Switch with Zu – 1 – 60 rails) 1 in 8½ 10 52 Kg/m Rail on PSC sleeper RT-5353 RT-5354 RT-4867 symmetrical split 1 in 8½ 11 60 Kg/m Rail on PSC sleeper RT-5353 RT-5354 RT-4967 symmetrical split 1 in 12 12 52 Kg/m Rail on PSC sleeper RT-5553 RT-5554 RT-4734 symmetrical split 1 in 12 13 60 Kg/m Rail on PSC sleeper RT-5553 RT-5554 RT-4220 symmetrical split 428 LWR through Points and Crossings: - The turnouts shall be isolated from LWR/CWR by provision of SEJs on either side. However, in case of LWR/CWR taken through turnouts the provisions contained in RDSO report no. CT-48 shall be followed. However, before permitting LWR through turnouts, specific approval of RDSO is required till the trials are completed. 429 Inspection and Maintenance of Points and Crossings:- (1) Maintenance – General (a) Points and crossings should be laid without the 1 in 20 cant unless otherwise specified in the drawing. (b) There should be no junction fishplates at stock rail joints or at the heel of crossings. (c) At least one rail on either side of the Points and Crossings should have the same section as the Points and Crossings assembly rail section. (d) It is desirable to weld stock and lead joints on the Points and Crossings assembly. (e) The use of spherical washer is necessary, where the shank of the bolt is not at right angles to the axis of the rail to obtain flush fit of the head of the nut of the bolt with the web of the rail. The spherical washers are used on skew side. (f) Notwithstanding the provisions of Sub-Para (e) above, the spherical washer should invariably be provided on the left side in switch assembly; as the orientation of fish- bolt hole is made accordingly. On crossing tapered washers are to be used on both sides. (g) Correct spacing of sleepers should be ensured according to the standard layout drawings. The standard spacing of sleepers for turnout for 1 in 8.5 and 1 in 12 turnouts are given in Annexure - 4/2. (h) The track geometry at the turnout should not be inferior to that applicable for the route. (i) The clearance, at the toe, heel of switch, at checkrail and wing rail must be Page 170 of 417 maintained within the tolerances prescribed in the schedule of dimensions. (j) The chairs and fastenings and all other fittings must be properly secured. (k) Packing under the sleepers must not be loose/ defective especially under crossing and the switch. (l) Cess should be low enough to permit efficient drainage and adequate depth of ballast cushion should be provided. (m) In case creep is observed at such layouts, the condition of elastic fastenings may be examined and suitable action be taken. (n) Where large number of Points and Crossings are being maintained within a specific area such as marshalling yards, large layouts of sidings, terminal stations etc., regular cycle of maintenance covering all Points and Crossings should be organized. (2) Maintenance of Switches – (a) The tongue rail and stock rail shall be fabricated in workshop as per standard RDSO drawings. Field officials should check the curvature of Stock Rail and Tongue Rail before laying. In case of Turn out taking off from curve suitable curvature as per resultant lead radius to be provided both in Stock Rail and Tongue Rail. (b) For information of field officials, the location of 13 mm head of tongue rail, Junction of head (JOH), location of level point of stock rail and tongue rail and its head thickness from ATS is given in Annexure - 4/5 (c) The condition of stock & tongue rails should be carefully examined and badly worn and damaged stock and tongue rails should be replaced. A tongue rail may be classified as worn/ damaged when- (Back to Para 717) (i) it is chipped/cracked over small lengths aggregating to 200 mm within a distance of 1000 mm from its toe. Chipped length will be the portion where tongue rail has worn out for a depth of more than 10 mm over a continuous length of 10 mm.(The tongue rail can, however, be reused after reconditioning of the broken/worn/ damaged tip by welding) (ii) it is badly twisted or bent and does not house properly against the stock rail causing a gap of 5 mm or more at the toe, the limit described in the IRSEM. (iii) wear on stock rail shall not exceed the limits laid down in Para 702 (1) (b). However, proper housing of tongue rails is to be ensured. Burred stock rail likely to obstruct the lock bar, should be replaced, if necessary. (d) Rail Gauge ties, rodding etc. hinder proper packing and hence at the time of packing points and crossing the signal staff should take out the rods and stretcher bars etc.to facilitate proper tamping. (e) To check the housing of the tongue rail and also the throw of the switch, all non – interlocked points should be operated by hand lever and other Points from the signal frame, when traffic permits doing so. (f) If the tongue rail is found to be not housing properly against the stock rail, the defect must be rectified by the Permanent Way Staff in case of non- interlocked points and jointly with signal and telecommunication staff, in case of interlocked or partially interlocked points. (g) Tongue rail should, preferably bear evenly on all the slide chairs. (h) When the tongue rail is in closed position, it must bear evenly against slide blocks. (i) Slight wide gauge at the toe of switch over and above the required widening to house the tip of the tongue rail, may be adjusted by providing suitable steel packing between the web of the stock rail and the lug of the slide chair wherever feasible. Page 171 of 417 (j) The Stretcher bar connected to the pull rod shall be maintained jointly by the Permanent Way Staff and the Signalling Staff. The gap between the top of the leading stretcher bar and bottom of stock rail should be between 1.5 mm to 5 mm. (k) All other stretcher bars shall be maintained by the JE/SSE/P.Way. Stretcher bars insulated for track circuit purposes shall not be interfered with unless signal staff are present. (l) Wear on switches can be reduced by lubrication of the gauge face of tongue rail. (3) Maintenance of Crossings – (a) If any damage to the nose of crossing is noticed, its cause must be traced, which might be due to tight gauge or due to excessive clearance at the checkrail. (b) To avoid hitting of nose, it shall be ensured that the checkrail clearance should be between 41 to 45 mm for fan-shaped turnout. (c) In obtuse Crossings, the distance between the throat and the nose must be maintained correctly. (d) In diamond crossings, obtuse crossings should be laid square to each other with respect to the centre line of the acute Crossings. (e) Maximum permissible vertical wear on wing rails or nose of crossing shall be 10 mm. However, on Rajdhani/ Shatabdi routes, as a good maintenance practice, crossing and the wing rails should be planned for reconditioning/resurfacing by welding on reaching the following wear limits: (Back to Para 717) (i) Built up/Welded Crossing – 6 mm (ii) CMS crossings – 8 mm Note – In case of CMS crossings, following dimensions should be deducted (to account for slope in casting of wing rails to 1 in 20 cant) from the wear measurements to find out the actual wear of wing rails and nose of crossing. (a) for 52 kg section – 2.0 mm. (b) for 60 kg section – 2.5 mm. (c) for heat-treated welded crossing – 3.5 mm. (4) Maintenance of lead portion and turn-in curve – (a) At the time of laying, the correct sleeper spacing should be ensured to achieve correct alignment of the lead curve. During maintenance, stations at 3.0 m intervals should be marked, versines checked, and track attended as necessary. The versine at each station in lead curve and turn in curve should not be beyond 3 mm, from its design value, as a good maintenance practice. (b) The versines of turn-in curves on loops should be recorded at stations at 3.0 m intervals on 6.0 m chord length during the inspection of points and crossings to check the sharpness of the curve and rectified as necessary. (c) The turn-in curve should also be checked for condition of sleepers and fastenings. (5) Inspections of Points and Crossings – (a) For Points and Crossings on PSC sleepers, the detailed inspection as per proforma given in Annexure - 4/3 should be done once in a year and all other intermediate inspections should be carried out as per proforma given in Annexure - 4/3 (A). The format for inspection of Diamond Crossings, Diamond Crossings with single and double slip are at Annexure - 4/4, 4/4(A), 4/4(B) Page 172 of 417 (b) The Divisional Engineer may inspect, at his discretion, a certain number of points and crossings particularly in running lines and those recommended for renewals. (c) All points inspected as per proforma mentioned in Sub-Para (a) above and entries to be made in TMS. (6) Cleaning and Lubrication of Points - At all interlocked and partially interlocked stations, the Signal staff will be responsible for the periodical cleaning and lubrication of those slide chairs in which signaling and interlocking gears are connected (generally upto third sleeper from toe of switch) in all points interlocked with signals or provided with locks. The SSE/JE/P. Way shall be responsible for the cleaning and lubrication of slide chairs of all hand operated points on their sections and remaining slide chairs of all points interlocked with signals or provided with locks. (7) Alterations of Points – The position of points and crossings should not be changed without the written authority of the Divisional Engineer. The sanction of the Commissioner of Railway Safety is necessary in the case of alterations/insertion/removal of points and crossings in existing running lines, however, shifting of points, which does not affect nature of signalling, will not require CRS sanction. (8) Gauge and Super-elevation in Turnouts – (a) It is a good practice to maintain reasonable uniform gauge over turnouts. Tolerance in gauge at various portions of turnout during new laying/renewal and maintenance shall be as given in Para 520 (3) (a) & Para 525 (1) respectively. (b) The gauge in crossing portion shall be 0 mm to 4 mm with respect to gauge prescribed in standard drawing, i.e., 1673 mm, both in case of New Laying/ Renewal and during service. (c) If gauge of track on either side of the points and crossings is maintained wider/tighter than the gauge on the points and crossings, the gauge on either side of the track should be brought to same gauge as in the points and crossings, as a good maintenance practice. (d) Super-elevation on turnouts with curve of similar or contrary flexure should be provided in accordance with Para 411 & 412. (9) Interlocking of Points – Before interlocking work is taken in hand, the JE/SSE/P.Way should – (a) Bring the rails to correct level and alignment. (b) Fully ballast and pack the points to be interlocked. (c) Mark the locations where the rods and wires have to cross the lines. (d) To avoid future adjustments of gear, see that the track at turnout, is laid to correct gauge so that switches, fittings and locks may be correctly put together. (e) Clear cess and bring it to the correct level and section where rods and wires have to be run. (f) Fit gauge ties wherever provided correctly to all switches. (10) Maintenance of Interlocked points- In the case of interlocked points, the JE/SSE (Signal) will be responsible for keeping the interlocking parts and apparatus in working order. As the slewing of the track at points is likely to throw them out of adjustment, such work should not be undertaken except in the presence of the Signal staff. On the advice of track defects from JE/SSE (Signal), JE/SSE/P.Way should promptly attend to them. (11) Date of Laying Points and Crossings – The month and year of laying a new or second hand points and crossings should be painted in white block letters on the webs of switches about 500 mm from the heel joint and the webs of crossings about 500 mm from the joint connected to the lead rails. Page 173 of 417 When second hand points and crossings are subsequently laid at another site, the dates previously marked should not be obliterated; an indication of the total life will then be available. In the case of reconditioning of switches and crossings, the date of reconditioning should also be painted. 430 Reconditioning of Switches and Crossing:- (1) General-There are two welding techniques used for reconditioning of crossings. Manual method consisting of H3B and H3C type of electrodes is used for reconditioning of switches and crossings. The reconditioning of switches shall be done on cess outside the track, Built-up crossings on cess or in-situ and CMS crossings in the depot / mobile depot. Robotic Welding Technology is used for in-situ reconditioning of CMS crossing on all routes having traffic density more than 30 GMT. On routes having traffic density up to 30 GMT and loop lines of all routes, decision regarding type of electrode / technology to be used for reconditioning of crossing is to be taken by CTE keeping in view local requirement and other relevant factors giving due consideration to the requirement that departmental workshops for reconditioning have to be kept functional with sufficient work load so that in-house capacity remains available and track maintenance does not suffer in case of failure / problems in contract awarding / execution. (2) Selection of Points and Crossings for Reconditioning. (a) Points and crossings to be reconditioned by welding should be in good condition and certified by the Sectional JE/SSE/P.Way for their suitability for reconditioning and should normally not have exceeded specified limit of wear. (b) Points and Crossings containing cracks on the worn-out portion having depth more than 3 mm (as determined by gouging) beyond the condemning size shall not be selected for further reconditioning. (c) Ultrasonic testing should be carried out to detect the serviceability. The Points & Crossings having internal defects should not be reconditioned. (d) Reconditioning of tongue rail shall be done on level cess / depot along with stock rail. (3) Competency of welder: Only skilled or highly skilled welder who has been trained and certified by competent authority in resurfacing of the crossings by welding shall be engaged. The competency of welder should be checked by Chemist and Metallurgist of Railway or officer nominated by CTE of the concerned Railway in case of departmental welders and by RDSO in case of non-departmental welder. A copy of competency certificate with identity card should be available with welder at the site of reconditioning. Competency given by OEM of the firm approved by RDSO will be accepted. (4) Welding Electrodes: (a) Electrodes of H3B and H3C class may be used for reconditioning, which have a minimum service life of 35 GMT and 50 GMT respectively. (b) Electrodes shall be sourced from RDSO approved vendors only. (5) Precautions for using electrode: (a) Welding should be done using 4 mm diameter electrodes only. (b) The electrode shall be stored in a dry storeroom. (c) Electrodes having cracked and damaged flux covering shall be discarded. (d) Electrodes shall be dried at 130° C to 170° C for at least one hour immediately before use. In case, the packing of electrodes is absolutely intact and all the electrodes are consumed within six hours after the opening of the packing, then preheating of electrodes may be dispensed with. Page 174 of 417 (6) Equipment for reconditioning: All the equipment as laid down in Para 6 of “Manual for reconditioning of medium manganese (MM) steel points and crossings, switch expansion joints and cast manganese steel (CMS)”should be available for reconditioning. (7) Reconditioning procedure: The procedure given in “Manual for reconditioning of medium manganese (MM) steel points and crossings, switch expansion joints and cast manganese steel (CMS)”should be followed. 431 Periodical Inspection of Reconditioned Points and Crossing:- After laying in track, the resurfaced points and crossing shall be inspected quarterly in order to record the amount of wear on the nose, left wing and right wing rail as well as stock and tongue rail and also for the structural soundness, presence of disintegration or any other defects. The wear shall be recorded in crossing at ten different locations marked (A1, A3, B1, B3, C1, C2, C3, D1, D2 & D3) as shown in Fig: 4.1 and in tongue rails at seven different locations starting from one at toe to places each 100 mm away towards heel side and up to 600 mm from the toe. Fig: 4.1 432 Robotic Reconditioning:- (1) The Robotic Welding technique uses a computer-controlled arc-welder that utilizes a coated wire without gas to eliminate operator exposure to weld fumes. The records of all welding Parameters and events are stored in memory for later reference. (2) For detailed welding process the manufacturer's manual may be referred to. Page 175 of 417 Annexure - 4/2 (Para 429) Table for spacing of Sleepers in 1 in 12 fan shaped Turnout (Taking off from Straight) Sleeper Spacing on gauge face on tongue rail for ML Spacing on gauge face of stock rail for ML No. side side Spacing Cumulative From SRJ Spacing Cumulative from SRJ 150 150 1 150 150 457 457 2 607 607 510 510 3 1117 1117 695 695 4 1812 1812 537 537 5 2349 2349 550 550 6 2899 2899 550 550 7 3449 3449 550 550 8 3999 3999 550 550 9 4549 4549 550 550 10 5099 5099 550 550 11 5649 5649 550 550 12 6199 6199 550 550 13 6749 6749 550 550 14 7299 7299 550 550 15 7849 7849 550 550 16 8399 8399 550 550 17 8949 8949 550 550 18 9499 9499 550 550 19 10049 10049 550 550 20 10599 10599 526 550 21 11125 11149 549 550 22 11674 11699 549 550 23 12223 12249 549 550 24 12772 12799 549 550 25 13321 13349 549 550 26 13870 13899 549 550 27 14419 14449 549 550 28 14968 14999 549 550 29 15517 15549 549 550 30 16066 16099 549 550 31 16615 16649 549 550 32 17164 17199 Page 176 of 417 549 550 33 17713 17749 549 550 34 18262 18299 549 550 35 18811 18849 549 550 36 19360 19399 548 550 37 19908 19949 549 550 38 20457 20499 549 550 39 21006 21049 549 550 40 21555 21599 549 550 41 22104 22149 549 550 42 22653 22699 549 550 43 23202 23249 549 550 44 23751 23799 549 550 45 24300 24349 549 550 46 24849 24899 549 550 47 25398 25449 549 550 48 25947 25999 549 550 49 26496 26549 549 550 50 27045 27099 549 550 51 27594 27649 549 550 52 28143 28199 549 550 53 28692 28749 549 550 54 29241 29299 549 550 55 29790 29849 549 550 56 30339 30399 549 550 57 30888 30949 549 550 58 31437 31499 549 550 59 31986 32049 549 550 60 32535 32599 548 550 61 33083 33149 549 550 62 33632 33699 549 550 63 34181 34249 549 550 64 34730 34799 549 550 65 35279 35349 550 550 66 35829 35899 550 550 67 36379 36449 550 550 68 36929 36999 550 550 Page 177 of 417 69 37479 37549 550 550 70 38029 38099 550 550 71 38579 38649 550 550 72 39129 39199 550 550 73 39679 39749 550 550 74 40229 40299 550 550 75 40779 40849 550 550 76 41329 41399 550 550 77 41879 41949 550 550 78 42429 42499 550 550 79 42979 43049 550 550 80 43529 43599 550 550 81 44079 44149 550 550 82 44629 44699 550 550 83 45179 45249 Page 178 of 417 Annexure - 4/2 (Para 429) Table for spacing of Sleepers in 1 in 8.5 fan shaped Turnout (Taking off from Straight) Sleeper Spacing on gauge face on tongue rail for ML Spacing on gauge Face of stock rail for ML No. side side Spacing Cumulative from SRJ Spacing Cumulative from SRJ 268 268 1 268 268 600 600 2 868 868 600 600 3 1468 1468 685 685 4 2153 2153 620 620 5 2773 2773 660 660 6 3433 3433 600 600 7 4033 4033 600 600 8 4633 4633 600 600 9 5233 5233 600 600 10 5833 5833 600 600 11 6433 6433 600 600 12 7033 7033 600 600 13 7633 7633 564 600 14 8197 8233 597 600 15 8794 8833 598 600 16 9392 9433 598 600 17 9990 10033 598 600 18 10588 10633 597 600 19 11185 11233 598 600 20 11783 11833 598 600 21 12381 12433 598 600 22 12979 13033 597 600 23 13576 13633 598 600 24 14174 14233 598 600 25 14772 14833 598 600 26 15370 15433 597 600 Page 179 of 417 27 15967 16033 598 600 28 16565 16633 598 600 29 17163 17233 598 600 30 17761 17833 597 600 31 18358 18433 598 600 32 18956 19033 598 600 33 19554 19633 598 600 34 20152 20233 597 600 35 20749 20833 598 600 36 21347 21433 598 600 37 21945 22033 598 600 38 22543 22633 597 600 39 23140 23233 598 600 40 23738 23833 598 600 41 24336 24433 598 600 42 24934 25033 550 550 43 25484 25583 550 550 44 26034 26133 550 550 45 26584 26683 550 550 46 27134 27233 550 550 47 27684 27783 550 550 48 28234 28333 550 550 49 28784 28883 550 550 50 29334 29433 550 550 51 29884 29983 550 550 52 30434 30533 550 550 53 30984 31083 550 550 54 31534 31633 Page 180 of 417 Annexure - 4/3 (Para 429) Page 181 of 417 Page 182 of 417 Page 183 of 417 Page 184 of 417 Annexure - 4/3 (A) (Para 429) Page 185 of 417 Page 186 of 417 Annexure - 4/4 (Para 429) Page 187 of 417 Page 188 of 417 Page 189 of 417 Annexure - 4/4(A) (Para 429) Page 190 of 417 Page 191 of 417 Page 192 of 417 Page 193 of 417 Page 194 of 417 Annexure - 4/4 (B) (Para 429) Page 195 of 417 Page 196 of 417 Page 197 of 417 Page 198 of 417 Page 199 of 417 Annexure - 4/5 (Para 429) PARTICULARS OF TONGUE RAILS SHOWING LOCATION AND HEAD THICKNESS AT LEVEL POINT OF STOCK AND TONGUE RAIL Location Location Location of Head of 13 mm of JOH level point of thickness S Description of switches Drg. No. of head from from stock & of tongue No. tongue rails ATS ATS tongue rail rail at level from ATS point mm mm mm mm 6400 mm c/s on PSC RT-4866/2 1 476.5 3023 1512 31.6 BG 52 kg RT-4866 6400 mm c/s on PSC RT-4966/1 2 476.5 3229 2348 48.25 BG 60 kg RT-4966 10125 mm c/s on PSC, RT-4325/1 3 1682 5836 4244 43.4 BG, 60 kg RT-4219 10125 mm c/s on PSC RT-4733/1 4 1682 5540 4029 40.34 BG 52 kg RT-4733 7000 mm c/s on PSC, RDSO/T-5364/1 5 RDSO/T-5364 for 52 kg to RDSO/T- 476 3095 1547.5 32 1 in 8 ½ Diamond 5364/3 7000 mm c/s on RDSO/T-6494/1 6 PSC,RDSO/T-6494 for to RDSO/T- 476 3008 2406 50 60 kg 1 in 8 ½ Diamond 6494/3 Page 200 of 417
