Dozens of London Overground passengers came close to walking on a live rail after a driver mistakenly evacuated a train in darkness, investigators have found.

The train had come to a halt due to a technical problem before it reached Peckham Rye station in south London. After a misunderstanding with controllers, the inexperienced driver told the 450 passengers they should leave the train and start walking to the station.

With the carriage doors locked, passengers went to the front of the train and climbed down steps from the driver’s cab in darkness on to slippery, uneven ground less than 12 inches from the 750-volt live rail.

The Rail Accident Investigation Branch (RAIB) found about 80 passengers, including elderly people and children, had climbed down and started walking the 30 metres along the track to the station before senior rail staff realised what was happening and stopped the evacuation. In a report on the incident published on Tuesday, they said the proximity of the passengers to the live rail “posed a significant risk of serious harm”.

Passengers were also seen stepping over the rail to take pictures, some of which were posted on social media, investigators said.

Simon French, the chief inspector of rail accidents, said it was “very fortunate that no one was hurt” after leaving the Overground service from Dalston Junction to Battersea Park just after 7pm on 7 November last year. The evacuation turned a “minor technical fault … into a potential safety incident”.

He said: “On this occasion, misunderstandings and confusion resulted in passengers being told to leave the safety of a train, climb down vertical steps above a live electric rail and walk in darkness along an overgrown path to a station. When dealing with this type of incident a train driver has many tasks to perform and, as we all know, stress can sometimes affect our ability to function properly.”

Eventually the driver, with advice from technicians, was able to resolve the train’s braking problem and move it into the station, where the remaining passengers disembarked after a delay of almost an hour.

The RAIB found that the driver was stressed as he attempted to address the breakdown, and was abused by some passengers, almost 200 of whom were having to stand during the delay. Control room staff instructing him had misunderstood the location of the stranded train. Investigators said Network Rail did not effectively implement its procedures for managing an incident involving a stranded train.

They also found that the Overground operator, Arriva Rail London, was not adequately prepared to manage the incident. The evacuation was halted by a Govia Thameslink Railway station manager.

Network Rail and Arriva have reviewed safety procedures since the incident. French said rail operators should carry out drills to prepare for such incidents.

“It’s not enough to have a plan, it must work when it is needed, and if it has never been practised, the chances are it won’t work,” he said.