Geometric Design

1. Unit 2- Track Geometrics
• Track Alignment
Direction and position given to the centre line of
the railway track on ground.
1. Horizontal (transition curves and
superelevation)
2. Vertical (grades and grade compensation)

2. Gradients (reduces length of track)
• Ruling
• Momentum
• Pusher/helper (uses helper/banking engine)
• Gradient for drainage considerations(1:1000)

3. Grade Compensation
• Gradients are reduced on curves to
compensate for the curve resistance
• Recommended values for GC are-
Gauge GC for each degree of curve
Broad gauge 0.04%
Metre gauge 0.03%
Narrow gauge 0.02%

4. Q.1- What should be the allowable ruling
gradient if a 3 degree curve is situated on a BG
track with ruling gradient of 1 in 200.
Ans- 1 in 264

5. Q.2- What should be the allowable ruling
gradient if a curve with radius 610m is situated
on a MG track with ruling gradient of 1 in 220.
Ans- 1 in 271

6. Speed of train

7. Speed of train

8. Super-elevation

9. Cant and cant deficiency

10. Q.3- Calculate equilibrium cant on an MG curve of 6
degree for an average speed of 50kmph. Also find
out the maximum permissible speed after allowing
maximum cant deficiency.
Ans-68.66mm and 64.47kmph

11. Transition curve

12. Q.4- Calculate length of transition curve required
on BG track for a maximum speed of 80kmph, after
allowing maximum cant deficiency.
Ans-118.8m

13. Q.5- Calculate length of transition curve required
on 5 degree BG track for a maximum speed of
90kmph, after allowing maximum cant deficiency.
Ans-118.8m

14. Widening of gauge on curves

15. Q.6- Calculate the widening of gauge for BG track
on a curve of radius 160m. Take diameter of wheel
as 1.5m and depth of wheel flange below top of rail
as 3.17cm .
Ans-3.38cm

16. Max. permissible speed

18. Q.7
Ans-109.8kmph

19. Q.8
Ans-83.13kmph

20. Q.ST
Calculate equilibrium cant on a MG curve of 8 degree for an average
speed of 55kmph. While evaluating for the maximum permissible speed
after allowing maximum cant deficiency, calculate for the required
length to set out a transition curve.

21. Q.ST
Calculate equilibrium cant on a MG curve of 5 degree
for an average speed of 70kmph. While evaluating for
the maximum permissible speed after allowing
maximum cant deficiency, calculate for the required
length to set out a transition curve

22. Negative super-elevation

23. Q 5- A 5 degree main track diverges from a 8
degree branch track of a BG layout. If max.
permissible speed on MT is 45kmph, calculate
for max. permissible speed on BT.
Ans- 34.8kmph

24. Q 6- A 6 degree BT diverges from a 3 degree MT
of a BG layout. If max. permissible speed on BT
is 30kmph, calculate for max. permissible speed
on MT.
Ans- 69.31kmph

25. Points and crossings

39. Turnout

40. Types of Turnouts

41. Crossing

44. Types of Crossing

45. Diamond crossing (Obtuse Angle
Crossing)

46. Terminologies
• Point/switch (toe, heel, throw, angle, split,
stub)
• Crossing (TNC, ANC and angle)
• Turnout
• Crossover
• Stretcher bar/switch motor/switch rod
• Rail(stock, tongue, straight lead, curve lead,
check(guard), wing)
• Facing direction and trailing direction
• Heel divergence, depth of heel block
• Flange-way clearance

47. Design of Diamond crossing

48. Design calculations for turnout

49. Different cases

50. Case-1

54. Q 4- Calculate for necessary elements for a
turnout on BG track having crossing number 1 in
12, heel divergence=13.5cm and curved tongue
rail portion between toe and TNC.
Ans- CL=40.224m, SL=11.446m, R0=485.202m,
Lead=28.778m

55. Case-3

58. Case-2
put x=0 in Case -3

59. Types of Railway stations
• Based on operational characteristics
1. Block stations (class A, B, C)
2. Non block stations (Class D, flag stations)
3. Special class
• Based on functional characteristics
1. Junction Stations (branch line joins main line)
2. Non- junction/ wayside Stations
3. Terminal Stations

60. Station Yards
• System of tracks for receiving, storing, sorting,
making up new trains.
Types:-
1. Passenger bogie
2. Goods
3. Marshalling (graveyard of locomotives, functions
as of reception, sorting and departure, its types
are flat, gravitational and hump)
4. Locomotive

61. Marshalling Yards