Paddington Train Disaster: Warning Systems

Prescott orders urgent scrutiny of safety systems

COMPETING RAIL safety systems, designed to stop trains passing through red signals, are to be subjected to independent scrutiny in the aftermath of the Paddington disaster. The move, ordered yesterday by John Prescott, the Deputy Prime Minister, marks a sharp about-turn by the Government.

COMPETING RAIL safety systems, designed to stop trains passing through red signals, are to be subjected to independent scrutiny in the aftermath of the Paddington disaster. The move, ordered yesterday by John Prescott, the Deputy Prime Minister, marks a sharp about-turn by the Government.

Having previously backed a "halfway house" device, Mr Prescott has bowed to mounting pressure to minimise the danger of rail travel and ordered that it should be tested against the more sophisticated - and expensive - automatic train-protection system (ATP).

The assessment will be separate from the public inquiry into the latest disaster, and will be carried out by Sir David Davies, president of the Royal Academy of Engineering. His initial findings are expected by the end of December.

"Yesterday's appalling accident outside Paddington has quite rightly focused attention yet again on railway safety systems," Mr Prescott said. Sir David would carry out an assessment of the available systems of train protection, including their "effectiveness, practicability and cost".

His report will also consider the increase in the number of signals passed at danger. Some 600 trains have passed through red lights in the past 12 months.

Last August, following a recommendation by the Health and Safety Executive, Mr Prescott said that the train-protection warning system (TPWS) should be introduced throughout the system by 2004. It was seen as better than the existing advance-warning system (AWS), but not as effective as ATP, which brings trains automatically to a halt at red lights.

ATP has only ever been fitted to a limited number of high-speed trains in Britain and is now being phased out by the industry. Experts believe it would have prevented the Paddington disaster.

The problem is that ATP would cost well over £1bn to introduce it throughout the network and the Government has accepted rail companies' arguments that the costs outweigh the benefits.

The AWS, possibly in operation on both trains on Tuesday, is the least sophisticated and the cheapest safety device. If a train has this system, a bell sounds in the cab when it goes through a green light and the service proceeds normally. When it approaches warning signals a klaxon sounds, which the driver has to acknowledge by pressing a button or the brakes are applied and it will come to a halt. Under normal conditions, drivers override the device and slow the trains gradually.

Where signals are against a train, the driver will first encounter a double yellow, then a yellow - which means the brakes should be gradually applied - and then finally a red light. There is a disc placed at eye level in the cab to one side of the driver, which shows black when the train is going through green lights, but turns to black and yellow spokes like a dart board when it is going through warning signals.

In the Southall disaster two years ago, a faulty AWS was switched off on the express train heading into London and the driver applied the brakes too late at a red signal.

In Tuesday's crash, some experts believe the system was suppressed because both trains were near Paddington station where speeds are considered to be too low to warrant its use. Others say the trains were too far out for the systems to be off and one of the drivers must have overridden the mechanism.

Where ATP is in use, an onboard computer monitors the state of signals in front of the train and advises the driver. If the computer is ignored the train will automatically reduce its speed. It cannot be cancelled out by the driver. Where AWS is "advisory", ATP is "supervisory".

In the wake of the Clapham inquiry, pilot ATP systems were introduced on the Great Western Line between London and Bristol and on the Chiltern Line. On Great Western, most trains are equipped with it, and since Southall all drivers have been familiarised with it; 90 per cent of services use it, according to the company.

The device is widely used in Sweden, Denmark and Holland, while the French and German railways use signalling systems which offer the same protection. However, British train-operating companies have consistently told the Government that it is too expensive.

So the decision was made to go for the TPWS, seen as an "add-on" to AWS. It can be overridden at double yellow and yellow lights, but not at red ones. It would not have prevented the Southall accident and may not have averted the Paddington disaster.

Alan Marshall, publisher of Rail News, said that the system favoured by Mr Prescott clearly helps where a train has gone through a red signal. However, at speeds above 60 or 70mph, it may be too late to prevent impact. "It clearly offers much less protection than ATP," he said.

Murray Hughes, editor of Railway Gazette International, said the Government must take its share of the blame for allowing the debate over the two systems to drag on. He estimated that TPWS gave 75 per cent of the benefits of ATP for between 10 and 20 per cent of the cost.

Government supporters argue that the £1bn could be better spent on other safety measures and that the number of lives saved would be small because Britain's rail safety record is good. Other experts contend that an even better procedure is being developed, the European train control system, which would be a better long-term bet than ATP for any £1bn investment.