turnouts in railways

this slides will contains some information about 'turnouts in railways', it's component parts and its classification. if any mistakes present, please tell me i will rectify them.

1. TURNOUTS IN RAILWAYS UNDER THE GUIDANCE OF V. MADDILETY RANGADU, M. TECH PRESENTED BY G. SRINIVASULU 14BC1A0124 1

2. CONTENTS 1. INTRODUCTION 2. COMPONENT PARTS OF TURNOUTS 3. OPERATION 4. CLASSIFICATION OF TURNOUTS 5. SAFETY 6. CONCLUSION 7. REFERENCES 2

3. INTRODUCTION A railway switch or turnout is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction. It consists of the pair of linked tapered rails known as the ‘points’ lying between the diverging outer rails, can be moved laterally in to one of two positions to direct a train coming from the point blades towards the straight path or the diverging path A train moving from the narrow ends towards the point blades is said to be executing a facing point movement, and the train coming from either of the converging direction passing through the narrow points is said to be tailing point movement A turnout generally consists of a straight through track and a diverging track. Right hand turnout have a diverging track to the right of the track and the left hand turnout have a diverging track to the left of the track 3

4. Turnout components POINTS STOCK RAILS FROG CLOSURE RAILS GUARD RAILS HEEL BLOCK SWITCH OPERATING DEVICE 4

5. points Switch rails or Point blades are the movable rails which guide the wheels towards either the straight or the diverging track. They are tapered on most switches, but on stub they have square ends 5

6. STOCK RAILS Stock rails are the running rails immediately alongside of the switch rails against which the switch rails lay when in the closed position. The stock rails are otherwise ordinary rails that are machined, drilled, and bent as required to suit the design of the turnout switch and the individual switch point rails 6

7. FROG The frog, also known as the common crossing, is the crossing point of two rails. This can be assembled out of several appropriately cut and bent pieces of rail or can be a single casting of manganese steel. On lines with heavy use the casting may be treated with explosive shock hardening to increase service life 7

8. CLOSURE RAILS Closure rails are the straight or curved rails that are positioned in between the heel of switch and the toe of frog 8

9. GUARD RAILS Guard rail (check rail) is a short piece of rail placed alongside the main (stock) rail opposite the frog. These exist to ensure that the wheels follow the appropriate flangeway through the frog and that the train does not derail 9

10. HEEL BLOCK Heel block assemblies are units placed at the heel of the switch that provide a splice with the contiguous closure rail and a location for the switch point rail to pivot at a fixed spread distance from the stock rail 10

11. SWITCH OPERATING DEVICE A switch operating device moves switch rails. Switch rails can be thrown (moved) from one orientation to another by either a hand-operated (manual) switch stand or a mechanically or electro-mechanically (power-operated) switch machine. In both cases, the operating devices are positioned at the beginning of the turnout opposite the switch-connecting rods near the point of the switch rails. 11

12. OPERATION When the wheels reach the switch, the wheels are guided along the route determined by which of the two points is connected to the track facing the switch. If the left point is connected, the left wheel will be guided along the rail of that point, and the train will diverge to the right. If the right point is connected, the right wheel's flange will be guided along the rail of that point, and the train will continue along the straight track. A mechanism is provided to move the points from one position to the other some switches are still controlled by a human operator. However, most are now operated by a remotely controlled electric motor 12

13. CLASSIFICATION OF TURNOUTS Single Crossover: A single crossover consists of two turnouts positioned in two tracks that allow the vehicle to go from one track to another. The two tracks are usually, but not always, parallel, and the turnouts are usually identical. A pair of single crossovers—one right hand and one left hand—that are arranged sequentially along the tracks is called a universal crossover. 13

14. Double Crossover: A double crossover sometimes called a scissors crossover consists of two crossovers of opposite hand orientation superimposed upon each other. In addition to the four turnouts involved, a track crossing diamond is needed between the two main tracks. A double crossover is typically used only when it is necessary to be able to switch from both tracks to the other in either direction, but there is insufficient space to install a universal crossover. 14

15. Track Crossing: Track crossings, as the name implies, permit two tracks to cross each other. Track crossings are often called either crossing diamonds or simply diamonds, due to their plan view shape 15

16. SLIP SWITCH A single slip switch works on the same principle as a double slip but provides for only one switching possibility. Trains approaching on one of the two crossing tracks can either continue over the crossing, or switch tracks to the other line 16

17. Lapped Turnouts: Lapped turnouts can be used to achieve a more compact track layout in constrained locations. In a lapped turnout, as seen in following picture, the switch rails for a second turnout will be placed between the switch and the frog of the initial turnout. This introduces a third frog where a closure rail of the first turnout crosses a closure rail of the second turnout 17

18. SAFETY Reversing the points under a moving train will almost always derail the train Points might move due to the extreme forces exerted by a passing train Interlockings that allow signals only to be cleared when switches are set correctly Track circuits to prevent reversing when a passing train is detected Electrical devices should be checked frequently 18

19. CONCLUSION On a lightly-trafficked line, with careful maintenance it can last for 25 years, but at a busy junction on a main line it may have to be replaced every 12 months. The work is usually carried out at night to avoid disrupting the timetable . When travelling through a turnout at speed, the safety of a train depends on accurate alignment of the switch-blades and associated gear. A rigorous maintenance regime is essential, and it doesn’t necessarily involve high technology . A set of turnouts may be trial assembled beforehand off site, to check that everything fits 19

20. REFERENCES Physicist Richard Feynman explains how a train stays on the tracks. BBC TV 'Fun to Imagine' (1983) Rules 8.9, 8.15, and 8.18, General Code of Operating Rules, Fifth Edition. (c) 2005 General Code of Operating Rules Committee Points and Crossings from Vossloh Cogifer   " 63 FR 39343 – Automatic Train Control and Advanced Civil Speed Enforcement System; Northeast Corridor Railroads" . Federal Railroad Administration . Retrieved 21 October 2012  Information on winter operation by dutch infrastructure manager Prorail (in dutch) Meyers, Marc A. (1994). Dynamic behavior of materials. New York: John Wiley. pp. 5; 570. ISBN 978-0-471-58262-5   " Scene of the Accident" .  The Argus . Melbourne: National Library of Australia. 29 January 1906. p. 7 . Retrieved 20 July 2011 20

21. THANK YOU… 21