Podcast
Questions and Answers
What is the purpose of comparing the proposed and existing versines?
What is the purpose of comparing the proposed and existing versines?
- To find the differences in the existing and proposed versines at each station (correct)
- To calculate the cumulative versine difference
- To determine the final versine at the last station
- To identify the correct alignment of the curve
What is the significance of the first summation at any station?
What is the significance of the first summation at any station?
- It represents half the slew required at each station
- It gives the cumulative versine difference at each station (correct)
- It is the final value at the last station
- It shows the difference between the proposed and existing versines at that station
What is the process to obtain the cumulative versine difference at Station No. 1?
What is the process to obtain the cumulative versine difference at Station No. 1?
- Multiply the versine difference of Station No. 1 with the cumulative versine difference of Station '0'
- Divide the versine difference of Station No. 1 by the cumulative versine difference of Station '0'
- Subtract the versine difference of Station No. 1 from the cumulative versine difference of Station '0'
- Add the versine difference of Station No. 1 to the cumulative versine difference of Station '0' (correct)
What is the theoretical representation of the second summation at any station?
What is the theoretical representation of the second summation at any station?
What is the initial value of the second summation at Station '0'?
What is the initial value of the second summation at Station '0'?
What is the purpose of calculating the second summation at each station?
What is the purpose of calculating the second summation at each station?
What is the significance of the figure against the last station in Column 5?
What is the significance of the figure against the last station in Column 5?
How is the cumulative versine difference calculated at each station?
How is the cumulative versine difference calculated at each station?
What is shown against Station No. 1 in Column 6?
What is shown against Station No. 1 in Column 6?
Why do correcting couples need to be applied?
Why do correcting couples need to be applied?
What happens when the final half-throw is negative?
What happens when the final half-throw is negative?
What is the purpose of calculating the length of transition?
What is the purpose of calculating the length of transition?
What is the formula to determine the radius of a curve?
What is the formula to determine the radius of a curve?
What is the consequence of not applying correcting couples?
What is the consequence of not applying correcting couples?
What is the length of the chord used to measure versines of a curve?
What is the length of the chord used to measure versines of a curve?
What is the reference level for a curve?
What is the reference level for a curve?
What is calculated in para 405?
What is calculated in para 405?
What happens when the final half-throw is positive?
What happens when the final half-throw is positive?
What is the degree of a curve with a radius of 1750 metres?
What is the degree of a curve with a radius of 1750 metres?
How are stations selected for applying correcting couples?
How are stations selected for applying correcting couples?
Why is the chord length used in measuring versines of a curve?
Why is the chord length used in measuring versines of a curve?
What is used to measure the versine of a curve?
What is used to measure the versine of a curve?
What is the interval at which measuring stations are located for measuring versines of a curve?
What is the interval at which measuring stations are located for measuring versines of a curve?
What is the purpose of checking the radii of turnout and turn-in curves?
What is the purpose of checking the radii of turnout and turn-in curves?
What is the rate of change of cant and cant deficiency used in formulas (a) and (b)?
What is the rate of change of cant and cant deficiency used in formulas (a) and (b)?
What is the maximum cant gradient used in formula (c)?
What is the maximum cant gradient used in formula (c)?
How should the length of transition curve be rounded off?
How should the length of transition curve be rounded off?
What is the minimum length of transition curve allowed in exceptional cases?
What is the minimum length of transition curve allowed in exceptional cases?
What is the maximum cant gradient allowed in exceptional cases?
What is the maximum cant gradient allowed in exceptional cases?
What is the purpose of reducing the length of transition curve in exceptional cases?
What is the purpose of reducing the length of transition curve in exceptional cases?
What is the recommended approach when the length of transition curve is restricted?
What is the recommended approach when the length of transition curve is restricted?
What is the goal of selecting a lower cant and/or cant deficiency in restricted cases?
What is the goal of selecting a lower cant and/or cant deficiency in restricted cases?
What is the requirement for altering or inserting points and crossings in existing running lines?
What is the requirement for altering or inserting points and crossings in existing running lines?
Under what condition is the sanction of the Commissioner of Railway Safety not required for shifting of points?
Under what condition is the sanction of the Commissioner of Railway Safety not required for shifting of points?
What is the tolerance in gauge at various portions of turnout during new laying or renewal?
What is the tolerance in gauge at various portions of turnout during new laying or renewal?
What is the recommended gauge in the crossing portion of a turnout?
What is the recommended gauge in the crossing portion of a turnout?
What should be done if the gauge of the track on either side of the points and crossings is maintained wider or tighter than the gauge on the points and crossings?
What should be done if the gauge of the track on either side of the points and crossings is maintained wider or tighter than the gauge on the points and crossings?
What should be done before interlocking work is taken in hand?
What should be done before interlocking work is taken in hand?
Why should the track at turnout be laid to correct gauge?
Why should the track at turnout be laid to correct gauge?
What should be done to the cess before running rods and wires?
What should be done to the cess before running rods and wires?
Study Notes
Curves and Turnouts
Determination of Radius
- The radius of a curve is determined by measuring the versine on a chord of known length.
- The formula to determine the radius is: R = (125 × C^2) / V, where R is the radius in metres, C is the chord length in metres, and V is the versine in millimetres.
Curve Designation
- Curves can be designated by their radius in metres or by their degree.
- The degree of a curve is the angle subtended at the centre by a chord of 30.5 metres.
- For example, a 1° curve has a radius of 1750 metres.
Measuring Versines
- 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 chords of 6 metres should be used, and the versine measuring stations should be located at every 3 metres.
Versine Measurement
- The versine is obtained by stretching a fishing/nylon cord or wire stretched between the end of the 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.
Reference Rail for Level
- The level of the inner rail of any curve is taken as the reference level.
Transition Curves
- The length of transition curves is calculated based on the rate of change of cant and cant deficiency.
- The formulae for calculating the length of transition curves are based on a rate of change of cant and cant deficiency of 35 mm per second, or a maximum cant gradient of 1 in 720 or 1.4 mm per metre.
Turnouts
Gauge and Super-elevation in Turnouts
- It is good practice to maintain a reasonable uniform gauge over turnouts.
- Tolerance in gauge at various portions of turnout during new laying/renewal and maintenance shall be as specified.
- The gauge in the crossing portion shall be 0 mm to 4 mm with respect to the gauge prescribed in standard drawings.
Interlocking of Points
- Before interlocking work is taken in hand, the JE/SSE/P.Way should bring the rails to correct level and alignment, fully ballast and pack the points to be interlocked, mark the locations where the rods and wires have to cross the lines, and ensure that the track at turnout is laid to correct gauge.
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Description
This quiz covers the concepts of curves and turnouts in civil engineering, including the determination of radius measurement and formulas. Test your knowledge of curves and turnouts in civil engineering.
