A safety investigation has revealed that a train came within 75 seconds of potentially crashing in Wandsworth after a "serious operational irregularity."

The near-miss at Balham station, occurred due to poor communication by Network Rail workers, the Rail Accident Investigation Branch (RAIB) said.

The investigation found that staff working from home had helped caused a breakdown in communication, with analysis of background noise during telephone calls suggesting their home environments "may have resulted in distraction."

Shortly after 7pm on April 20 last year, a tamping machine was mistakenly driven onto a line which had not been closed to trains during the maintenance work.

It crossed a junction through which a Southern train from London Victoria to East Grinstead had passed just 75 seconds earlier.

Wandsworth Times:

The investigation found that the mistake happened because the person responsible for train movements in the area where the work was taking place provided "incomplete information" about the location of the tamping machine.

It was noted that the two people who shared this role during the weekend when the work was taking place spent a "significant proportion" of time working from their homes, amid a lack of "clear guidance" on where they should be based.

Analysis of background noise during telephone conversations suggests their home environments "may have resulted in distraction", according to the report.

Safety critical communications were "poor throughout" and resulted in "no party having a clear understanding" of where the tamping machine should be, the RAIB stated.

Chief inspector of rail accidents Simon French said several people involved in the Balham incident failed to challenge information or instructions which were confusing and inconsistent.

"This is not the first time this has led to trouble, and the consequences can be disastrous," he warned.

"Our investigation found a culture of poor communications among staff involved with engineering work. People were embarrassed to use the proper protocols when passing messages to colleagues.

"The aviation industry confronted this problem head-on many years ago, and now any pilot or air traffic controller who does not use the correct form of words and phrases would instantly stand out as less than competent.

"We are challenging the railway industry to come into line with aviation, and embed the same standards among its people."

Network Rail route director Shaun King said: "The safety of all those who use the railway is our top priority, and we take our responsibilities very seriously to ensure safety is maintained.

"We understand that communication at this time was not at the level expected and we will continue to work closely with RAIB and consider any recommendations made."