ANTI COLLISION SYSTEMFOR

TRAINS

WHAT IS AN ANTI COLLISION SYSTEM ?

The anti collision systems for trains is an electronic device designed to ensure the safety and proper operation of the trains in order to avoid the risk of dangerous and unexpected collisions of the trains which may be caused due to human errors and equipment failures.

IR Based System

There is an IR transmitter and an IR sensor fitted on the Train’s Locomotive.

System works in Line Of Sight(LOS).

The sensor is connected to the Braking circuit which is connected to a stepper motor which applies brakes to the train.

TYPES OF ACD’S

DRAWBACKSIR system only works in the Line Of Sight (LOS) i.e the system fails on curved tracks.

It cannot prevent REAR-END collisions, SIDE-TRACK collisions.

The range of the system depends on the IR transmitter power. The more power , the lesser is the reaction time.

This system is drastically affected by whether conditions as rains and other conditions interfere with the IR signal.

GPS Based ACD

Conceptualized by B. Rajaram director of konkan railways.

Self-acting microprocessor based electronic device.

Takes inputs from the G.P.S satellites and network with other A.C.D’s to detect any collision like situation.

Range of 3 km.

Prevent head-on collisions, side track collisions, rear-end collisions.

Can be installed on the locomotives, guard vans ,at stations and at level crossings .

The Loco ACD (Fixed & Moving) is permanently installed in the locomotive along with its ABU( Automatic Braking Unit) .

The Guard ACD (Portable & Moving) is portable A.C.D and acts as a backup for the locomotive A.C.D in case the locomotive A.C.D stops transmitting the signal .

The Station ACD is permanently installed in the stationmaster’s office. He can send manual SOS through his station ACD by pressing SOS buttons when he notices anything unusual like a hot axle or fire in a train while performing train passing duties.

The Level Crossing Gate ACD is permanently installed in a Gate Man’s cubicle and informs other A.C.D’s about any emergency at the LC.

A.C.D units comprising the whole A.C.D network

A glance at the G.P.S based ACD unit

Fig 2.3 Unit for Locomotive

COMPONENTS of ACD

G.P.S (Global Positioning System)- Get the position updates

C.C.U (Command and Control Unit)- Decision making device

Radio Trans-reciever- For inter-ACD communications

(A.B.U) Automatic Braking Unit

Working of an A.C.D functional unit

TRAINS COME TO A HALT IF ON A COLLISION PATH (AUTOMATICALLY)

AUTOMATIC BRAKING UNITGets input from C.C.U Apply normal brakes/ emergency brakes

A.C.D’S exchange info and the C.C.U takes a decision based on a working rule

RADIO TRANS-RECIEVERTransmits the Train ID , Speed, Location

Receives info sent by other A.C.D’s (within 3 km range)

C.C.U (BRAIN)Extract parametersLATTITUDE LONGITUDE SPEED ANGLE DATE & TIME

G.P.S Picks up signal from the satellites(exclusive network of Satellites)

Submits data to C.C.Ufor further processing

CONSTELLATION of SATELLITES

Deduce if the trains are on a collision path

Driver Console ( L215 x W80 x H125)

L 9 9 9 9 9

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DRIVER'S CONSOLE

KONKAN RAILWAY CORPORATION LTD.

SOS ACD-OK ACD-M

Scenario - Gate Approach

• Train approaches the Gate ST 346 At approximately 2000m from the Gate ‘Gate Approach’ message and audio buzzer appears for 10 seconds

S T 3 4 6 G A T E A P P R O A C H

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Scenario – Gate OPEN

S T 3 4 6 G A T E O P E N

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• Level Crossing Gate ST 346 is detected to be OPEN – Audio Visual Indication is automatically activated to draw the attention of the Driver and brakes are applied to reduce the speed to 15 Km/h.

Scenario – Gate occupied

• Level Crossing Gate ST 346 is detected to be occupied by the road vehicle - Audio Visual Indication is automatically activated to draw the attention of the Driver and brakes are applied to reduce the speed to 15 Km/h.

S T 3 4 6 G A T E O C C U P I E D

1 9 : 2 6

Situations where A.C.D can prevent a collision

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2.

3.

Situations where A.C.D can’t prevent a collision (Worst Case Scenario)

In the following cases the A.C.D network fails

Other train is a ‘NON’ ACD Train – ACD functions by reacting to another ACD, as such if one of the two trains is a non-ACD train, the protection against collision will be missing.

‘Adequate’ braking distance at that speed is not available when a ‘dangerous’ collision-like situation arises suddenly – However, severity of the collision would be reduced as a function of the reaction time.

‘Failure’ of brake power of the Locomotive/train – This situation arises when there is any electrical failure and the brakes become non functional.

BENEFITS OF THE ACD SYSTEM

Acts automatically to prevent collisions if an eventuality arises. Does not depend on human action.

Designed and engineered to make the system very rugged, and able to withstand harsh environments

The Loco ACD operates directly from the engine battery; the LC gate ACD can be powered by solar power systems, if required.

Very economical and cost effective.

Does not degrade the existing safety level.

No cabling on the track required (which is more expensive and cumbersome).

It does not require any inputs to be fed by the crew at the start of journey, thus human error is eliminated.

CONCLUSION

Through this innovative technique of early sensing of any possible collision scenario and avoiding it thereof, we demonstrate that it is possible to improve the overall safety of the railway system in India and the number of collision incidents can be significantly reduced.

REFERENCES

Indian railway vision 020.Government of India, Ministry of Railway, (Railway Board) December 2009.A concept for reducing railway accidents. H Ben Brown, Jr. Gregg Podnar, Mel Siegel, February, 2005. “Safety as Key Business Theme! -Indian Railways Perspective”, P. C. Sharma & Amitabh, International Railway Safety Conference, 2004, Perth, Australia.White Paper- Safety on Indian Railways, April 2003, Govt. of India, Ministry of Railways.Indian Railways Corporate Safety Plan (2003-13), August 2003, Govt. of India, Ministry of Railways.Channel model for train to train communication using the 400 MHZ band Christina rico Garcia, Andréa Lehner, institute of communication and navigation 82230Wessling GermanyRailway crossing collision avoidance system. Shirley et al. - September, 2001Wireless Communication for Signaling in Mass Transit Larcenous, Regis, SiemensTransportation Systems, 26 Sept, 2003. This presentation describes Siemens efforts to develop advanced data radio systems for RATP and NYCT.Quantification of the business benefits of positive train control Prepared for the Federal Railroad Administration, Revised March 15, 2004.

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