Issue dated - 2nd August 2004


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Konkan Railway deploys Anti Collision Device

The design and deployment of an Anti Collision Device by Konkan Railway will reduce train accidents, both man-made and natural, along the 760 kilometres of difficult terrain. AKHTAR PASHA reports

B Rajaram says that since the ACD does not need any complex infrastructure for its operation, it can easily be implemented in any railway system in the world

ACCIDENTS involving trains are gruesome. There’s the magnitude of the loss involved, both of life and property, and the trauma it causes to the families of the passengers on board.

In railway operations, it is the driver who is virtually driving blind in the block section because his vision does not cover the braking distance of a train, and only at stations does he have signals to guide him. A simple misjudgement of the colour of a signal at a station can lead to a major mishap, notwithstanding the huge investment made in wiring the signals. Many a time, trains on the same lines have collided head-on and caused hundreds of passengers to lose their lives.

How safety will improve

The Anti Collision Device (ACD) is a self-acting microprocessor-based data communication device designed and developed by Konkan Railway (KR). When installed on locomotives (along with an auto braking unit-ABU), guard vans, stations and level-crossing gates (both manned and unmanned), the network of ACD systems prevents high-speed collisions in mid-sections, station areas and at level-crossing gates, thereby saving the lives of rail passengers and road users. The ACD uses both radio frequency and global positioning system (GPS) through satellites, whereby a train is automatically brought to a halt if the track ahead is not clear. The train starts braking three kilometres ahead of a blockade.

The ACD was conceptualised by B Rajaram, managing director of KR. He presented the vision of the world’s first ACD prototype mounted on locomotives in December 1999. The prototype has undergone extensive field tests in the Indian Railways over the last three years, and has been cleared by the ministry of railways for adoption. Says Rajaram, “As it does not need any complex infrastructure for its operation, it can easily be implemented in any railway system in the world.”

In rail systems, two inherent aspects make collision prevention very difficult. First, the braking distance of a fast-moving train is of the order of 1.3 kilometres. Second, most of the safety inter-lock systems used in the railways depend on correcting human action.

ACD Ahoy!

The ACDs will be installed at all stations, level crossings, locomotives and guard vans. On the KR route, these are also installed at soil or laterite cuttings where they couple with inclinometers (designed and made by KR) to give pre-warnings of failing cuttings. KR is hopeful of making train travel safer for the public by implementing the concept of a ‘Networked ACD System’ in train operations. While travelling in the mid-sections, loco ACDs remain on the look-out for trains present within a radius of three kilometres to handle potentially dangerous collision-like situations. Rajaram cites some examples.

  • The Loco ACD (Fixed & Moving) is permanently installed in the locomotive along with its ABU. In case a train detects another train approaching it on the same track, the loco ACDs of both trains apply brakes to bring their respective trains to a halt, thus reducing the impact of a head-on-collision if it takes place at all. While entering the station area, if the loco ACD detects the presence of a train standing or moving away on the main line, it automatically regulates its train’s speed to what is the maximum permitted over turnouts, thereby reducing the chances of a collision.
  • The Guard ACD (Portable & Moving) is portable so that it can be removed easily from SLRs/Brake Vans along with its antennae. The guard ACD keeps monitoring the transmission of its loco ACD and acts as a stand-by protection to the train if the loco ACD stops radiating. The guard can send manual SOS (Save Our Souls) through its guard ACD by pressing its SOS button when he observes dragging of detailed coaches close to his brake van or notices fire in a running train.
  • 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. If a train while approaching a level-crossing detects its gates in an open condition, its loco ACD regulates the speed of the train and warns the driver to take appropriate action, thereby reducing the chance of the train colliding with a road vehicle. At unmanned level-crossings, a stand-alone anti-theft arrangement is made for fixing of the ACD system along with the provision of solar-powered secondary battery charging equipment.

ACDs exchange ‘data’ and ‘commands’ with each other when they are within their ‘radio-range’ of influence, and also accept ‘specific’ manual inputs in emergencies or for initialisation purposes. Based on the relevant train working rules programmed inside, the ACDs take decisions automatically, act independently, and appraise the user whenever necessary, through appropriate audio, video or text interfaces.

Inside the ACD

The heart of the ACD is an Intel 80386 processor that uses the DM&P M617 Intel chipset. It [ACD] has an integrated digital radio modem and works on the VxWorks Real Time Operating System (RTOS). Rajaram adds, “VxWorks, as a platform, is most suitable for real-time applications.”

The entire 760 kilometres of KR, from Roha to Thokur, is protected with the ACD network route. The ACDs are deployed and linked to 53 stations, 80 manned and 27 unmanned gates, 98 locomotives, 50 guard vans and 179 inclinometer-protected cuttings. The cost of the ACD deployment on KR is approximately Rs 35 crore. The same ACD will be deployed on the rest of the Indian Railways at an estimated cost of Rs 1,600 crore for 64,000 kilometres of rail routes.

Lives to save

Rajaram explains, “As anywhere else where the ACD will be commissioned, the ACD network on the KR route will also prevent all types of collision-related accidents at stations, gates, mid-sections and the like.” Additionally, on the Konkan route, it will work in tandem with inclinometers to give pre-warning of possible collapse of a soil/laterite cutting, and reduce the speed of the approaching train. ACDs will thus lead to safer travel.

Features of an ACD
  • Comprises six independent ACDs, viz. Loco ACD, Guard Van ACD, Station ACD, Manned Level-crossing Gate (MLCG) ACD, Unmanned Level-crossing Gate (UMLCG) ACD and ACD Repeater interconnected by an UHF communication network.
  • 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 and ACD repeater can be powered by solar power systems, if required.

Functions of an ACD
  • All ACDs within a radius of three kilometres continuously communicate among themselves giving their ID, status, location, speed, etc.
  • Whenever a potential collision is sensed, the loco ACD applies the brakes automatically.
  • It uses an intelligent braking system to ensure optimum braking and minimises loss of operational time.

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