Monday, October 18, 2010

Signalling the right change
Collision prevention systems in Railways.

The recentcollision at Badarwas station… After many such collisions with several fatalities, the focus has shifted to the prevention of collisions in mid-sections due to human error.
P.R. Goundan
V. Shanker
The collision between a goods train and an express train at Badarwas Railway Station near Shivpuri recently, preceded by another devastating collision between two express trains at Sainthia in West Bengal, as also several other collisions/ near-misses with relatively less casualties have brought to fore the need for a dependable collision prevention system on Indian Railways (IR). But the issues involved are rather complex, both in terms of technology and management.
The following issues remain the Achilles' heel of railway safety:
Absence of a dependable aid that can pick up and act on a danger signal, even if the driver fails to do so due to fatigue or other reasons.
Absence of redundancy in existing signalling systems.
Inadequacies in staffing pattern that hamper quick mobility of signal maintenance personnel, whose services are required round-the clock, and
Low motivation levels and morale among the signalling supervisors and officers, who feel they have little say in key decisions affecting them.
Finding the right technology
Globally, most railways have adopted highly-reliable signalling systems with adequate redundancy and safety-rated systems that get activated automatically whenever the driver overlooks signals. In the past decade, the ETCS (European Train Control System) has been evolved by a consortium of European countries, mainly to ensure inter-operability of systems supplied by multiple vendors.
In 2008-09, Indian Railways introduced as a trial run an ETCS-1-compliant system for about 42 EMU trains in the Chennai-Gummudipoondi section of Southern Railway. The on-board equipment either stops the train immediately (if the signal is at danger) or regulates the speed suitably (if the obstacle is some distance ahead). Similar works have been sanctioned on the Eastern Railway, the suburban sections of South Eastern Railway and short sections of the main line on two other Railways.
However, the Southern Railway's system has not achieved the expected reliability standards yet, primarily due to the difference in the Electro-Magnetic Interference (EMI) environment of the EMUs and European Railways.
The high death toll in the Gaisal accident on the Northeast Frontier (NF) Railway in 1999 saw the focus shift to the prevention of collisions in mid-sections due to human error.
Emergency warnings
The Konkan Railway Corporation (KRCL) demonstrated, under simulated conditions, the Anti-Collision Device (ACD) based on GPS (Global Positioning System) tracking, with additional algorithms to differentiate the up and down main lines. This design assigns a unique track identification number to the trains running on a particular line and applies brakes if trains with the same ID move towards each other and exceed the prescribed minimum separation
The trains communicate their location and track ID to each other through a common UHF communication channel, which can alsobe used to warn other trains during an emergency such as derailment or provide advance warning at level-crossing gates. Inputs from station signalling are necessary to establish the train's track ID.
However, when the ACD was tried out on a large scale on the NF Railway during 2006-07, it was not precise enough to detect adjacent lines in stations. Thus it can only reduce train speeds on various loop lines but cannot prevent a collision at the speed permissible on loop lines at a station. The ACD system at times failed to detect trains on the same track or wrongly detected regular up and down movements on parallel lines as safety–threatening situations. Although there are international (UIC) specifications for vital, safety-rated signalling systemsthe designers of the ACD deemed it a non-vital, non-signalling device for assisting drivers that did not require international validation.
Vital signalling systems
Kernex Micro Systems, the outsourced technology partner of KRCL, has exclusive rights over the ACD design and for manufacturing, installation and maintenance over IR. Thus, any train anti-collision system, which largely plays a monitoring role and steps in only in rare instances of human failure, should necessarily be 99.9 per cent efficient. While the ETCS level-1 protection systems can help avert human errors, the ACD has useful features, such as conveying emergency warnings to nearby trains and advance warnings at level crossings.
During the transition phase, it would be practical to have two protection systems onboard, performing different roles. Alongside these, a highly-reliable block signalling system can avert collisions in block sections (except during derailments on adjacent lines). This can be achieved by duplicating all the sub-systems (cable routes, track detection devices, Block Instruments, power supplies).
However, no signalling system can be effective in absolute block territory when the station-signalling or block-signalling has failed or is not available; a 100 per cent reliable block signalling system is the answer.
Raising staff morale
The Railways have to realize that there are theoretical and practical limitations to the reliability of existing signalling equipment. Since there is a premium on the reliability of these systems, there have to be massive investments towards enhancement of signalling and telecom assets.
The maintenance and project organisations should be sufficiently staffed to handle the increase in workload; the morale of the staff of the maintenance and project organizations have to be raised by according the Signalling and Telecom wing representation at the Railway Board Member level. All staff related matters, policy decisions and inter-departmental co-ordination can be dealt effectively only by the Railway Board Member as per the present set- up; functioning under a different Member with different priorities will not be conducive to achieving the high expectations from the signalling department.
Half-hearted attempts that fail to address these core issues will not significantly alter the ground reality for collision-prevention systems or the safety of the ordinary railway passenger.
(P. R. Goundan is a former Additional Member (Telecom) Railway Board and former GM, ICF. V. Shanker is a former Addl Member (Signals) Railway Board and a former GM, CLW. Their views are personal.)


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