The Bedford train crash that killed a driver and left scores of passengers injured could have been prevented if a safety measure to stop trains from passing red lights had been installed, it has been claimed.

Safety measures designed to stop trains from being involved in accidents after passing red 'danger' signals have come under the spotlight following the fatal accident on the Midland Main Line south of Bedford on June 19.

East Midlands Railway (EMR) driver Shaun Burton, 60, was killed on impact after his train crashed into the rear of another EMR train that had stopped on the same line. The front train was halted by a fault with its Automatic Warning System, or AWS.

Black box data showed Mr Burton's train applied the brakes nine seconds before the collision, and managed to decelerate from 76mph to 49mph before impact.

However, investigators from the Rail Accident Investigation Branch (RAIB) have found that his train did not stop at a red signal automatically activated after the front train stopped - known in the industry as a 'signal passed at danger' or SPAD.

Questions have been raised as to why the track was not fitted with a safety measure that could have prevented the second train from proceeding past red signals at all.

Called TPWS (Train Protection and Warning System), the failsafe is deployed on much of the UK's train network and uses trackside electromagnets to force units to stop if they pass through a red signal.

But Network Rail is understood to have assessed the route as having a 'low risk' of a crash in the event of a SPAD. It views TPWS as a 'back-up' system deployed as a last resort on high risk lines where crashes are more likely.

Dave Calfe, general secretary of drivers' union ASLEF, believes the crash could have been averted had it been installed.

'What will concern passengers and what concerns us is that there are safety systems that can be put in place to prevent such accidents happening and the network should have been able to cope,' he said earlier this week.

'TPWS has been installed throughout much of Britain's rail network. Unfortunately, TPWS had not been installed here.

'If TPWS had been installed, this accident would not have happened, the driver would not have died and no passengers would have been injured.'

TPWS was rolled out between 2000 and 2003 following a series of fatal disasters in which SPADs had played a role, including the 1997 Southall disaster which killed seven and the horrifying 1999 Paddington crash which killed 31.

The system has proven effective: the number of 'potentially severe' SPAD events dropped almost 60 per cent between April 2003 and March 2004 and now average just 11 a year, compared to 134 in 2001-2002. Fatalities have also dropped significantly.

However, it is expensive: the initial roll-out cost £575million and Sir John Armitt, then chief executive of Network Rail, told a House of Commons transport committee it would save 65 lives over 25 years - £8.8million per 'life saved'.

A 2001 enquiry launched in the wake of disasters such as Paddington recommended that TPWS is fitted to all high-speed rail lines.

While trains can hit 125mph on the Midland line, Network Rail has only opted to fit it in 'high risk' areas where crashes are likely, such as close to converging railway lines or end-of-line buffer stops.

It is understood that because the line south of Bedford is considered a 'plain line' with none of these complications, railway bosses chosen not to install TPWS.

'[Network Rail] have to make a risk assessment and the assessment was that this junction was generally safe,' one railway expert told the Mail.

'That may have been a mistake, and it might have prevented an accident, but there are probably thousands of junctions that don't have TPWS.

'There is always a limitation to what can be spent.'

Some experts believe passengers would assume it is ubiquitous on British trains.

Rail engineer Gareth Dennis said on social media: 'I think it is quite reasonable to assume that most passengers expect that level of protection across the whole railway, and I expect a lot of questions going 'why isn't there?'

Investigators will also be looking at whether another safety measure - the Automatic Warning System, or AWS - performed as expected on the evening of the crash.

Developed after the calamitous 1952 Harrow and Wealdstone disaster that killed 112 after a train passed several red signals, it uses a series of trackside magnets to alert a driver to upcoming yellow or red signals using an audible horn.

Drivers must acknowledge the alarm by pressing a dedicated button in the train cab in a matter of seconds, or the train will automatically initiate an emergency stop.

But AWS also has an Achilles' heel: once a driver has acknowledged the alarm, there is nothing stopping them from passing a red signal anyway if their line does not have TPWS.

Investigators are looking at why the front train's AWS appeared to activate when it was not meant to, and continue examining onboard CCTV to assess the AWS on Mr Burton's train. They are also checking if the trackside magnets were doing their job.

Network Rail did not provide a comment in response to questions from the Mail, citing the ongoing RAIB investigation.

Ellie Burrows, its regional managing director, said earlier this week that the infrastructure body was 'deeply sorry' and remained 'fully committed' to supporting the probe.

She added: 'Incidents like this are extremely rare on Britain's railways which remain among the safest in the world but, when they do happen, we are determined to fully understand why.'

She further vowed that Network Rail would 'act quickly on any lessons' to be learned once investigations have concluded.

Passenger services on the Midland Main Line are set to resume on Monday following a multi-day operation to recover the locomotives from the line.

The intensive undertaking saw overhead lines removed, a temporary road made and two 110-tonne rail-mounted cranes deployed to lift the carriages off the rails.