REGINA - The Transportation Safety Board says a runaway rail car that rumbled through seven public street crossings at a speed that reached 30 km/h had been left unattended with inadequate braking.

The tanker filled with asphalt covered more than four kilometres before it came to rest in a Regina neighbourhood last March, the board said in a report released Tuesday.

"What didn't happen that should have occurred is physical securement of that rail car," said senior investigator Jerry Berriault.

The car was being handled by a crew from Cando Rail Services at the city's Co-op refinery when it rolled away just after 11:35 p.m. on March 1, 2016.

Investigators determined the crew left the tanker unattended and secured only by emergency air brakes, which slowly lost pressure until they released. The report notes the hand brakes had not been applied nor had the crew performed tests to see how effective they were.

Transport Canada had ordered railway companies a few months earlier to bolster the securement of their equipment. The order followed an investigation into the 2013 explosion and fire in Lac-Megantic, Que., in which 47 people died after a runaway train carrying crude oil rolled down a grade and derailed in the community's downtown.

Several people employed by the rail company were charged with failing to ensure the train was properly braked before it was left unattended for the night.

The crew working the night the Regina rail car rolled off was not supervised, the report says.

"If company supervision is not consistent and does not engage all employees directly, unsafe work practices and adaptations may not be detected, and the risk of a serious accident or incident occurring is increased," it says.

"If rules or instructions permit the use of air brakes alone to secure rolling stock left standing in a yard, there is an increased risk of rolling stock running away uncontrolled."

The report indicates the number of cases of runaway train equipment in Canada jumped to 33 in 2015 from 21 the previous year. There were 27 cases last year.

Investigators found the Cando crew failed to make an emergency radio broadcast to warn other rail traffic about the runaway tanker and crew members were unable to catch the unit with a locomotive.

Transport Canada fined Cando Rail Services for violating the Railway Safety Act and the Canadian Rail Operating Rules.

The report says Cando has since conducted a review of its safety rules with its employees.

There was another runaway rail car in Saskatchewan in 2016. An empty hopper car belonging to Canadian Pacific Railway rolled through a rail yard in Saskatoon and across two public level crossings before coming to a stop.

News from © The Canadian Press, 2017