Gerald Riley
Principal Operations Specialist, Rail Operations, RSSB
An electric train’s system detects a problem with the overhead line and its pantograph drops to prevent further damage.
The driver gets out to check and reports back that he can’t see anything wrong, though before normal working resumes, the electrification team have to make an informed decision. It appears to be a minor electrical fault, yet the incident and how it is resolved can have an impact that ripples across the system and causes disproportionate disruption.
A speed restriction of 20mph applies on the affected line even if the train hasn’t got a pantograph or can pass with the pan lowered and operate on diesel power.
And although the fault has affected only one running line, instructions in the Rule Book are interpreted as applying to all adjacent lines, which could be as many as three or four, needing to run at the reduced speed. Even though there’s reasonable confidence that those lines are not impacted, the restrictions stay in place.
We end up with serious issues: trains not moving, disruption and delays to services, overcrowding on platforms, even staff being verbally or physically assaulted by members of the public who are unhappy about their journey being disrupted.
Improving electrical safety
So, we set about revising some of the instructions on electrical safety in the Rule Book. These changes will come into force on 6 June 2026.
In order that trains not powered by overhead electric lines can move through at normal speed on the affected line, we’ve amended the instructions to say that the 20 mph rule applies to ‘any train that's going to pass with a raised pantograph’.
The rule’s intention was also that only trains on the line on which the incident originally occurred would have a restricted speed.
So, we have said explicitly that it is only necessary for trains to continue to run at caution and no more than 20 mph on the line on which the problem was reported.
They are small revisions but ones that have a significant effect. They address issues that, while hardly spectacular on the surface, had potential to strike at services like a bolt from the blue. From now on though, it’s more of a flash in the pan.