ANTI COLLISION DEVICE (RAKSHA KAVACH)
DEFINITION:-
Anti Collision Device is a network of “self -acting” computer based communication devices which automatically apply Brakes to trains, thereby protecting the travelling public as well as road users at level crossing Gates from “collision” related accidents. It comprises of a central processing unit (CPU), a global positioning system (GPS), receiver and data radio modem for communication with other ACDS. It is a fully integrated Electronic Control System designed to minimize collision and increase safety on Railway system. It is a non -signaling system and provides additional over safety in train operation to prevent dangerous train collision caused due to human reasons or limitations and equipment failure. Being a non-Signaling and inter locking system it does not replace any existing signaling and inter locking system and does not alter any procedure of train operations in vogue. The world’s first ACD was taken into use on 19-10-1990 in Konkan Railway.
a. On board computers use inputs from Global positioning system (GPS) for determination of train location, speed, course of travel and time. Both mobile and stationary components of ACD system exchange information and take decisions based on train working rules and embedded software to apply brakes automatically without any inputs from the users. If two ACDs are deemed to be at a risk of collision the ACD system activates automatic braking operation to prevent collision. Loco ACD is designed to interface with various types of braking system of locomotives.
b. ACD comprises verities of devices such as board(mobile). ACD for locomotives and Guard vans and track-sides (stationary) ACDs, level crossing ACDs, Loco shed ACDs, .and sensor based ACDs and ACD, Repeaters. All these work on the principle of distributed control systems. All ACD along the ACD route communicate with each other through radio communication when they are within a redial range of at least 3kms.
c. If two ACD units are within a predefined distance from each other and deemed to be at risk of collision, the ACD system activates automatic braking operation to prevent collision. ACD system provides audio-visual warning to the road users of level crossing Gate when train is approaching. In non- interlocked manned LC gates, when approaching loco ACD detects ‘Gate open’ condition, the speed of the train/Loco is regulated, preventing level crossing Accident.
d. Loco ACD warns the Loco pilot when the engine approaches a system. More over the Loco pilot, Guard, station master can stop the train in the event of any unusual, by applying SOS button, Now a day’s these devices a have already been applied in Konkan Railway North-east Frontier Railway. In near future it shall be used in whole Indian Railway.
e. Purpose of ACD system:-
It works as “companion” to Driver
- To alert Driver on station approach.
- To prevent “high” speed collisions in mid- section.
- To prevent “high” speed collisions in ‘Station Area’.
f. The ACD system provides capability to perform the following-
- Detection and prevention of Head on collision.
- Detection and prevention of Rear-end collision.
- Detection and prevention of side-collision in block sections in both directions.
- Detection and prevention of collision due to fouling.
- Detection of Train parting/Jumbling and alerting approaching trains.
- Station approach warning for driver Speed limit imposition.
- Approach warning for road users. SOS functionality.
Types of ACDs :-
1. LOCO ACD : installed in locomotive along with auto braking unit (ABU), Loco Pilot’s console, radio and GPS antennae. ( on board ACD ).
2. GUARD ACD : a portable ACD loaded in the SLR/ on the roof of goods brake van along with radio and GPS antennae.(on board ACD ).
3. STATION ACD : installed in SM’s office ( operating room ) along with SM’s console, radio antennae, power supply module, battery etc.
4. MANNED L.C. GATEACD: installed at manned L C. gate along with radio antennae, power supply module, battery & other accessories including open/close indicator for gateman.
5. UNMANNED L.C. GATEACD: installed at unmanned level crossing along with radio antennae, power supply module, battery etc.
6. ACD REPEATER :installed along with radio antennae, power supply module, battery and other accessories at locations identified as inter-ACD communicating shadow zones for providing continuous radio communication coverage.
7. TID ASSIGNING ACD : located just before the ACD territory for assigning track- ID (identity) to the loco ACD automatically before the train / locomotive enters the ACD territory. it is installed at a station in rear of the first station of ACD territory.
8. LOCO SHED BAHARLINE ACD:installed in loco shed along with LF’Sconsole, radio antennae and other accessories.
i) All ACD units communicate with each other via radio when within a radius of up to 3000 metres.
ii) GPS determines train location, speed, course angle of travel and time.
iii) ACD system activates automatic braking operation (through ABU) to prevent collision.
PERFORMANCE OF ACD :-
- Detects and prevents Head-on and Rear-end collision.
- Detects and prevents Side collision in block section in both directions.
- Detects and prevents collision due to fouling.
- Detects Train parting / Jumbling and alerts approaching train.
- Speed limit imposition.
- Train approaching warning for road users.
- SOS functionality.
WHAT CANNOT BE DONE BY ACD :-
- It cannot prevent collision with non-ACD train.
- It cannot prevent collision when ACD is out of order.
- It cannot prevent collision when ABU has failed or isolated.
- It cannot prevent collision when brake power of the train is poor.
- It cannot prevent collision during TID-FS. However speed is automatically reduced to 25 KMPH.
- It cannot detect parting / jumbling when Guard
-ACD is within shadow zone or no GuardACD is attached.
DUTIES OF SM/ASM
- Ensure that ‘ACD-OK’ indication is available and ‘ACD-M’ indication is not lit up.
- Treat the station ACD as failed when ‘ACD-M’ indication appears or ‘ACD-OK’ indication disappears and advise SCR and Maintenance staff.
- Arrange for safe custody of guard ACD with fittings if necessary for operational reasons and advise the same to SCR/Guard lobby of base depot.
- In emergency SM can stop any train (with LOCO ACD) by pressing TWIN SOS buttons of SM’S console. all trains within 3 kms radial distance will stop.
- These trains can move not exceeding 15 kmph till move beyond 3 kms radial distance or ‘SOS’ is cancelled at source.
- ‘SOS’ can be cancelled by pressing cancellation button twice in succession.
- Read the message, note in register and acknowledge by pressing ‘MESSAGE ACK’ button.
- Necessary messages to be relayed to SCR / Maintainer.
- Columns of the said register –Sl. No., date, time, message text and action taken by SM.
- When buzzer sounds observe the indications / message and take N/A..
- Audio-buzzer stops automatically after 10 seconds.
- Check and record in diary and rough journal the status of the Guard-ACD at the time of taking over and making over, of the same.
- The on duty Gateman will be responsible for safe custody of ACD.
- If the gate ‘open’ indication is lit up even after closing the gate, treat the gate ACD as failed and inform SM.
It is not possible to generate SOS message from GATE ACD nor possible to cancel it
