Signal Sighting Guidelines PDF

Annexure: 19-A1 (Sheet 2 of 3) S. Guidelines for Signal Sighting - For shifting of existing Signals/erection of new Signals No 1 Factors to be considered for Locating a signal (a) Please refer to Para no: 7.1.13, 7.1.14 of SEM for placement of Signals. (b) A Stop signal shall be a...

Annexure: 19-A1 (Sheet 2 of 3) S. Guidelines for Signal Sighting - For shifting of existing Signals/erection of new Signals No 1 Factors to be considered for Locating a signal (a) Please refer to Para no: 7.1.13, 7.1.14 of SEM for placement of Signals. (b) A Stop signal shall be avoided (as far as possible) in risky location, where Train will stop on steep gradients/Girder Bridge/viaduct/Culvert/Cutting/Obstruction to Road/Theft prone area/vicinity of chemical factories. (c) Minimum visibility in MACLS territory: Distant signal: 400 meters, Stop signal: 200 meters. Please refer to Para no: 7.1.11. (d) Height of normal aspect of the Colour Light signal shall be approximately at 3.65 meter. (e) No external light shall dominate a signal aspect. If it cannot be resolved, proper screen shall be provided behind the signal unit to improve contrast. (f) Intermediate block signal shall be located, so as to split block section into near halves. It shall not be provided in a Block section with heavy and continuous falling gradients steeper than 1 in 80 unless the brake power of trains on the section is adequate to enable the trains being stopped at IB Signal. (g) Automatic signal shall be located normally with a spacing of one km from each other subject to other considerations and headway required. It shall not be provided in a Block section with heavy and continuous falling gradients steeper than 1 in 80 unless the brake power of trains on the section is adequate to enable the trains being stopped at each of the Automatic Stop Signals. (h) Any signal, if proposed on Right Hand side, requires prior approval of Competent authority. Right Hand signal shall be provided with a retro reflective type of arrow to indicate the line to which it pertains to. Note: (i) Till a signal is brought in to use, signal unit shall be turned away from direction of Traffic. No testing of signal aspects shall be done in the face of an approaching train, by turning signal towards direction of Traffic. (ii) when a signal is not in use, it shall be distinguished by two crossed bars (X) across it, each bar being not less than one metre long and 10 cm wide. (GR 3.18) (iii) Signals not in use shall not be lit. (GR3.18 (3)) (i) When signals are going to be in close proximity, they may be combined as per Para 7.1.16. (i) Under approved special instructions, a colour light Distant signal may be combined with the last Stop signal of a station in rear or with an Intermediate Block signal or with a Stop signal protecting a level crossing. (Ref: GR: 3.07(7) , G.S.R. 157(E).-Dated-05-3-21) (ii) Where proposed IB signal location and a mid section Gate are in proximity, IB signal shall be so located, to protect LC gate also. Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 416 of 530  Annexure: 19-A1 (Sheet 3 of 3) 2 Schedule of dimension (SOD) - Considerations (a) Minimum horizontal distance from centre of the track (Implantation) to any structure as per schedule of dimension. Please refer Annexure: 19-A2 of SEM (b) Each signal post shall be marked with it`s Centre to centre (Implantation) distance to track/ Tracks in Black colour in white background for Normal Implantation and in Red colour with white background for reduced implantation. (c) If any signal post and/or any of it`s components are infringing with schedule of dimensions, such post shall be painted with alternate Red & white stripes at Loco Pilot`s eye level (3.65 m) and it`s Centre to centre distance to adjacent Track(s) shall be marked in red colour on a white background on the signal post itself, showing an arrow towards infringing track, for easy identification. 3 Precautions in RE area extract from ACTM para 16.4 to 16.5 of Appendix I (a) If any portion of a signal post or its fittings falls within 2 meters of a 25 KV live conductor, or any it`s metal part, such portion shall be protected by an iron screening solidly connected to the structure. If not, a Caution Board shall be provided on the signal post at a height of 3 meters above the rail level, to caution the staff. (b) Neutral section shall be located away from stop signals, level crossing. If neutral section is provided after a stop signal, the distance* between signal and neutral section shall be such that after stopping, the train shall be able to pick up enough speed to coast through the neutral section without any risk of stalling. If neutral section is provided before a stop signal, the distance* between neutral section and signal shall be such that the train shall not cross the signal in an effort to coast the neutral section. *Note: The distance should be preferably 1600 meter away on section with gradient up to 1 in 300 and 2500 meter with higher steeper gradient up to 1 in 200, if unavoidable. If PTFE type short neutral section has been used, this distance can be reduced to at least 400 meter after the stop signal and 200 meter before the stop signal. 4 Please also refer to Extracts of Para 20.5 of Appendix-1: Manual of AC Traction - Volume II (Part-II) for placement of signals in RE area, given at Annexure: 22-A1. 5 Any other stipulation as given by Railway Board & RDSO from time to time shall also be followed. Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 417 of 530 Para no: 19.2.1 Annexure: 19-A2 Extract of Schedule of Dimensions (SOD) The minimum horizontal distance from centre of the track to any structure as per schedule of dimension (SOD) (addendum & corrigendum slip no (ACS) no 26 dated 10.1.2019) shall be as follows: New works or S. For existing From Level to Level alterations to No works existing works 1 From rail level to 305 mm above rail level 1675 mm 1905 mm 2 From 305 mm above rail level to 3355 mm 2135 mm 1905 mm increasing 3 From 305 mm above rail level to 1065 mm to 2360 mm 4 From 1065 mm above rail level to 3735 mm 2360 mm 2135 mm 5 From 3355 mm above rail level to 4115 mm decreasing to 1980 mm 2360 mm 6 From 3735 mm above rail level to 4420 mm decreasing to 2135 mm 2135 mm 7 From 4420 mm above rail level to 4610 mm decreasing to 1980 mm 8 From 4115 mm above rail level to 6250 mm 1600 mm 9 From 4610 mm above rail level to 6250 mm 1600 mm 10 Below rail level up to formation level of the track 2575 mm 2575 mm on straight and curves up to radius of 875 m 11 Below rail level up to formation level of the track 2725 mm 2725 mm on straight and curves with radius less than 875 m Note: Latest Amendments of SOD as issued from time to time shall be followed. Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 418 of 530 Para No. 19.11.7(d) Annexure: 19-A3 Method for Finding Out the Resistance of an Earth The typical connection diagram used for measurement of earth resistance from ‘Fall of Potential’ method is given below: The earth resistance may be measured as per ‘fall of potential’ method using four terminal earth tester, as given below: (i) Connect Current probe C1 & Potential probe P1 to the earth electrode(s) under test. (ii) Drive a probe onto the earth 30 to 60 meter away from the earth electrode(s) under test and connect to terminal C2. In case of earthing system having multiple earth electrode like ring earth, the Current probe C2 should be in the direction which is away from the set of electrode(s) under test. This probe should be driven to a depth of 15 to 30 cm. (iii) Drive another probe onto the earth midway between the electrode(s) under test and probe C2. Connect this probe to terminal P2. This probe should also be driven to a depth of 15 to 30 cm. (iv) Measure the earth resistance. Say it is Reading 1. (v) Move the potential probe P2 by 3 meter farther away from the electrode(s) under test and do the earth measurement. Say it is Reading 2. (vi) Move the potential probe P2 by 3 meter (from midway) towards the earth electrode(s) under test as shown in figure above and do the third measurement of earth resistance. Say it is Reading 3. (vii) If all the three reading are within a few percent of their average, then average of the three readings may be taken as the earth resistance of electrode(s) under test. Note: In case there is a significant variation of three measurements from their average, then location of test probe C2 may be shifted to a farther distance and test may be repeated. Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 419 of 530