The photo shows a 130mm (five-inch) gap where track has crumbled away. RMT says that it was taken at the beginning of last week on the InterCity East Coast Mainline at Colton Junction just south of York.
The original crack had been identified on inspection and painted blue to mark it down for repair or replacement. However, it took four days to replace it, RMT says, during which time a train could have derailed, jumped the tracks and collided with an on-coming service.
Although train running speeds were reduced from 125mph to 90 miles an hour over the missing track, RMT says that that is ‘a wholly inadequate response’ and called for Network Rail to take over direct responsibility for maintenance work instead of contracting it out.
RMT general secretary Bob Crow said: "This shocking picture highlights the reality on Britain's railways today, staffing and inspections have been cuts in the dash to save money and there is massive pressure right from the top of government to keep services running at all costs regardless of the potential human cost.
"This is exactly the same set of poisonous conditions that lead us to the Hatfield disaster and as this picture shows we are dicing with death and risking another major rail tragedy. RMT is demanding action before it is too late.
"For a kick off we want all cuts to staffing, maintenance and renewals reversed and all track works brought back in house rather than subbed-out to contractors. The current contractor staff should be transferred over to direct Network Rail employment. We also want the pressure from the centre to run services at any costs lifted to enable safety-critical works to take place immediately.
"Finally, we want an end to the further cuts proposed by the government in its McNulty Rail Review before we end up with another rail tragedy on Britain's tracks with ministers paraded on our screens with blood on their hands."