Thirty new streetcars on the road in Toronto are experiencing mechanical problems more often than expected, says a staff report to be presented to the Toronto Transit Commission board this week.

The TTC, however, said on the weekend that the "failures" are not of concern yet, not undermining rider safety and not a sign that the new streetcars from Bombardier are unreliable vehicles.

Brad Ross, spokesperson for the TTC, said the problems are "growing pains". The TTC tracks overall performance every month in its chief executive officer's report. The January 2017 report will be considered by the TTC board on Wednesday. 

"With any new vehicle like the streetcar, there are going to be growing pains," Ross said. "There are going to be teething issues. And the issues we are seeing are very minor."

According to the report, "failures" were reported every 5,696 kilometres that they in service November 2016. The target distance between "failures" for the new streetcars is 35,000 kilometres. 

Mechanical problems include doors that didn't open properly, brake issues of some kind, and intercom systems that didn't work.

The problems are plotted in a graph entitled, "Mean Distance Between Failures," which means the distance travelled before a mechanical problem occurs and is fixed.

New Streetcars: Mean Distance Between Failures

TTC's staff report for January 2017 contains this graph that shows 'mean distance between failures' for its new streetcars. That means the distance travelled before the new streetcars on the road experience mechanical problems. (TTC Chief Executive Officer's Report January 2017)

"It's like a breaking-in period," Ross said. "For a complicated vehicle like a new streetcar, there are going to be issues."

When the TTC has 60 new streetcars in service, then the statistics will matter, he said. He predicted by then many of the mechanical problems will have been fixed and the distance between "failures" will be greater.

"The statistic in the report is not one that really concerns us because we only have 30 cars. We actually will need to have 60 of the new streetcars before any sort of failures become a concern for us."

Next new streetcar due to arrive this week

The next new streetcar is scheduled to be delivered by Bombardier this week. Forty new ones in all are expected this year.

The report says: "As the TTC awaits the delivery of more new low-floor streetcars from Bombardier, this key performance indicator will become increasingly relevant. With so few of the new streetcars in service today, the performance indicator does not yet truly reflect just how well the new streetcars are performing.

"Even a low number of defects can have a significant impact on the mean distance between failures. The target of 35,000 mean kilometres between failures is expected to be attained on a regular basis as the sixtieth new streetcar is received."

Brad Ross, TTC Spokesperson

TTC's Brad Ross says mechanical problems being experienced by the transit agency's 30 new streetcars are not a concern yet. (Mehrdad Nazarahari/CBC)

But Ross said the TTC is tracking the problems because it needs to know how the vehicles are performing when on the road and in service, even though they are still under warranty.

"Because it's a brand new vehicle, we need to make sure that there isn't a systematic problem with the fleet," he said.

"Is this something that the manufacturer needs to go back and tweak and repair, at the production stage? Or is this something that is a one-off for reasons that are explainable or not explainable, depending on what the issue is?"

Ross said the new streetcars have to travel 600 kilometres "trouble-free" before they are actually put into service. And once in service, problems are tracked. During peak service, the TTC has 23 new streetcars in service on 510 Spadina, 514 Cherry and 509 Harbourfront lines. Seven are kept back for training and routine maintenance.

"We had this with the new subway trains, and now, they're great trains."

The TTC expects to have 70 of the Bombardier built streetcars by the end of this year and to have all 204 by end of 2019.

Toronto expects to have 40 more new streetcars delivered this year. (David Donnelly/CBC)