It is now known that 100 people were injured in Friday’s train crash near Bedford, in which the driver of one of the trains was killed. Sim Harris asks what lessons might be learnt.

The earliest railway engineers were well aware of the risks of a rear-end collision.

The time interval system was supposed to protect each train by not allowing another to follow for a given number of minutes.

This control was carried by policemen at the lineside, who would stop or at least caution the driver of a second train if not enough minutes had elapsed.

Inevitably, this system was flawed, even if sufficient time had passed, because the first train could have broken down just out of sight.

As a result, the guard became responsible for protecting a stationary train, and the invention of detonators in 1841 made this simpler. The guard would run back, clipping detonators to the rail at set intervals. If a driver heard the explosion of a detonator he would make an immediate emergency brake application and, with luck, stop in time.

The introduction of the telegraph and the absolute block system which depended on it improved safety, because only one train was allowed to enter each ‘block’ until the signalman at the far end confirmed that the train had now passed his box, leaving the previous block clear for a following train.

Modern signalling still reflects the block principle, and the introduction of systems to warn a driver of an adverse signal goes back to 1906, when the Great Western Railway devised a method of audibly warning a driver that a distant signal was ‘on’ – in other words, showing caution.

A second version added a brake application, which would be made automatically if the driver did not acknowledge the warning.

After nationalisation in 1948, British Railways standardised its new AWS system, basing it on an alternative version introduced by the LMS.

We now have TPWS – the Train Protection and Warning System – which will also take control and stop the train if a signal is overrun or approached too fast. TPWS is not perfect, partly because it is not effective at speeds of over 75mph, and it will be replaced by the European Train Control System, which is now being fitted on the East Coast Main Line between London and Stoke tunnel, which is just south of Grantham.

But in spite of absolute block rear collisions continued, and the worse on record during peacetime was the disaster at Harrow & Wealdstone in October 1952, when an up overnight express from Perth collided with a suburban train.

The rear end collision south of Bedford on the Midland Main Line on Friday should not have happened, in theory. The stationary train (we don’t yet know why it had come to a stand in mid-section at Elstow) from Nottingham was hit by a following train from Corby.

The first train should have been protected by red signals, and the second train should have been stopped in time.

Why this did not happen is a matter for the Rail Accident Investigation Branch, and their inspectors will have been gathering evidence from train crew, passengers and signallers.

But railway accidents can often lead to calls for new safety measures, although not always successfully.

The collision in 2004 between a Great Western HST and a car on the level crossing at Ufton Nervet, west of Reading, caused a catastrophic derailment and cost the lives of six people on the train, as well as the car driver, who had apparently intended to commit suicide.

The father of a teenage girl who had been killed by being thrown through a broken window called for seat belts to be fitted to trains, but the Rail Safety and Standards Board concluded that they could make matters worse, while the majority of passengers would probably not wear them. In addition, enforcing their use, as on aeroplanes, would not be feasible.

One witness of Friday’s accident near Bedford told the BBC’s Today programme: ‘The people in first class ended up with stomach and rib injuries, because they went into the tables they have in first class, and EMR trains, the way that they’re structured with seats, was probably the worst way it could have been structured for a train crash.

‘They face each other in the three by three and the two by three, and … when people flew into one another, the seats that they were on, like, broke backwards into the people behind them.’

This appears to raise questions about the security of seats which are clipped to rails on the floor rather than built in, as in older rolling stock.

No doubt this account has been noted by the RAIB inspectors, and perhaps we will hear more about the safety of modern train seats in due course.

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