Two weeks ago the STM said the Azur trains were going to resume service promptly, however since then only one of the new trains is running.

It turns out the problem that forced all the Azur trains off the rails in mid-January is harder to fix than originally thought .

Every Azur train was pulled from service on Jan. 14 after severe damage to the tracks at the Du College station.

It turned out that grooves worn in the rails by the decades-old MR-73 trains were not connecting well with the contact shoes used by the Azur trains.

The Azur contact shoes were wearing down very quickly, and being pushed out of the grooves when turning at high speeds.

One train was repaired, and safety measures installed to make sure the type of damage that happened in January wouldn't happen again.

Now the STM has determined the new model Azur contact shoes are wearing out too fast.

"The more train in service the effect is accelerated by that. The problem is with the bronze part of the pick up shoe and it is not present on the MR73 rolling stock2E," said Francois Chamberland, director of engineering at the STM.

Instead, the Azur trains are going to have their shoes swapped out for the model used on the older trains.

This retrofit will, unfortunately, delay the resumption of service on the Azur tnains, and delay the trains being built.

"It must fit exactly our part and it must be produced," said Chamberland. "It's not a standard part that you can buy at the corner. It has to be fabricated."

Three more Azur trains will be ready by Friday Feb. 17.

Since the Jan. 14 incident the frequency of service on the metro line has been reduced, with the time between trains increased by 30 seconds.

Marie-Claude Leonard, executive director of metro service, said the STM has noticed an increase in congestion on platforms.

"We have more people in the train, on the platform," said Leonard.

She said the STM has changed staffing, with more people on the platforms at 30 stations during rush hour in order to help speed things up.