Management errors are partly to blame for a massive shutdown of the Vancouver region's SkyTrain light-rail system last month that had been pinned on a sole transit electrician, says a union official citing an internal company report.

Bill Magri, president of CUPE local 7000, said the unnamed electrician who was blamed for the shutdown is now allowed back at work after being suspended for two days after the July 21 shutdown that stranded thousands of passengers.

Mr. Magri said in an interview on Friday that the internal report on the actions of the worker indicates that management actions deepened the problem. He said the report is vague on what management did to worsen the situation, but hopes the investigation will provide a full accounting.

Story continues below advertisement

The union declined to provide a copy of the report, because it deals with a personnel matter. The company that operates SkyTrain would not confirm or deny the report.

"What [the electrician] did was not the causal factor of the massive failure," Mr. Magri said, referring to the report, which he said he read last week. "It would have caused the failure, but certainly not one of the proportions that were experienced that day. Had the issue stayed with his one incident, they delay would likely have been an hour or less."

He said management errors compounded the situation, though the issue remains the subject of an investigation.

"It was only after what [the electrician] did and supervisors got involved that it started to snowball," said Mr. Magri, basing his statement on his own reading of the report. "Had it have been left with what he did, the catastrophic failure would likely not have happened."

In a statement Friday responding to a Globe and Mail query on the union allegations, the general manager of the B.C. Rapid Transit Company that operates SkyTrain said it was "completely inappropriate for anyone who has inside knowledge of a confidential internal document that includes sensitive employee information to publicly disclose details of the document."

Fred Cummings wrote that the internal report on the "root cause" of the events of July 21 is still being finalized and that he did not want to compromise a continuing independent review by Gary McNeil, the former CEO of the Toronto region's GO Transit. That report is due by the end of October and will be released to the public.

Mr. Magri said the electrician got a verbal warning – the "minimal discipline" possible in such a case. "That says his participation in all this was minimal."

Story continues below advertisement

Mr. Magri said he has just returned from vacation and has not had an opportunity to speak with the worker because the employee is on holidays.

The worker could go through a grievance procedure to have the discipline removed from his file, the union president said. "We're undecided right now until I can talk to the member."

TransLink, the regional transit authority, has said the July 21 chaos – the second major shutdown in five days – came about after a loss of power when the main power control panel at the SkyTrain operations centre in Burnaby was accidentally taken out of service while it was being modified.

The shutdown was blamed on a mistake by the electrician installing a circuit breaker at the operations centre. The rare procedure was required to align the system with the Evergreen Line to the northeastern suburbs of Vancouver, under construction and expected to launch in 2016.

The electrician was working on the power line that supplies the main control room, meaning communication and train control were affected. "It brought our system to its knees," Mr. Cummings told The Globe and Mail days after the incident.

On July 17, the system went offline due to a premature failure of a computer system. Together, the two systems were an unprecedented blow to the transit system, which was opened in the 1980s and has since been expanded.

Story continues below advertisement

During a media tour of the centre earlier this week, officials with TransLink and the rapid-transit company declined comment on specifics about the shutdowns pending the outcome of Mr. McNeil's review.