A second LRT train has derailed in as many months at Ottawa's Belfast Yard storage and maintenance facility.

A train came off the tracks sometime early Monday morning, CBC has learned. A similar incident occurred in early May.

But unlike the last time, when city officials held a news conference on the sidewalk across the street from the yard, the city is now refusing to comment on what exactly what went wrong, or whether the train was damaged.

Instead, the city told CBC to contact Rideau Transit Group (RTG), the consortium building the $2.1-billion east-west line, even though under the LRT contract communications for the massive project is generally the responsibility of the city.

RTG initially neither answered nor acknowledged requests for comment.

But after an earlier version of this story was published, an RTG spokeswoman sent a point-form response, characterizing the incident as "minor."

The note said that there were no injuries, that the issue was "rectified within hours" and that preliminary reports indicated it caused minimal damage to the train.

RTG did not say, however, what caused the wheels to come off the track.

Video of the last derailment on May 3.

2nd derailment

The derailment happened somewhere at Belfast Yard, where the trains are manoeuvred manually and move at slow speed.

A train also derailed there on May 3. In that incident, one of the two-car train's 10 wheel sets left the track at around 5 a.m. while the train was about to begin daily testing.

Hours later, reporters were summoned to a news conference with Troy Charter, the city's director of transit operations, and Claude Jacob, the general manager of the maintenance arm of RTG. They characterized the derailment as a minor setback.

At the time, Jacob said derailments "are absolutely normal," but it's unclear what an acceptable frequency is for trains to come off the tracks, or in what circumstances it is acceptable.

Rideau Transit Group's Peter Lauch, left, and Alstom's Henri Poupart-Lafarge, centre, told Ottawa Mayor Jim Watson that they could hand over the LRT by mid- to late August. (Kate Porter/CBC)

Update on LRT delayed

The Confederation Line, running 12.5 kilometres from Blair to Tunney's Pasture, is more than a year late. RTG had hoped to hand the LRT over to the city by Canada Day — its fourth target date for completion — but wasn't able to deliver.

Last week, Mayor Jim Watson called executives from RTG and train maker Alstom to his office to express his frustration at the ongoing delays. After that meeting, Watson said Alstom promised to have all 34 trains working by July 7, and that RTG would finish the complex light rail system by mid- to late August.

Monthly LRT updates usually occur on the first Tuesday of each month during a meeting of the city's finance and economic development committee, which is chaired by the mayor.

But in July, the mayor's office moved the finance committee meeting to the morning of July 10, the day of the last council meeting before the summer break.