Day four of public hearings in the inquiry into Ottawa’s light rail transit system saw the train manufacturer Alstom take the hot seat at the University of Ottawa.

Appearing remotely, Yves Declercq of Alstom told the hearing the Citadis Dualis model in Ottawa had never been used before and is the longest light rail train in North America.

In French, Declercq says Alstom was approached by Rideau Transit Group in July 2012 to make a proposal for a train. He says the company had two weeks to repurpose a train to meet the city of Ottawa’s requirements.

The commission heard that the city wanted a longer vehicle to meet the capacity goal of 24,000 passengers an hour.

"We noticed that the ridership request was quite exceptional, it was the actual ridership for a subway and not for an LRT," Declercq said. "The desire of the city of Ottawa was to have 24,000 per hour in every direction that is the size of a subway train."

Delercq told the commission that the capacity requirement is not only a matter of how many people who can be aboard the trains, but it is also question of speed, distance between vehicles on the line, and a change in acceleration profile. Declercq said the old model of Citadis train had eight doors, while the new one in Ottawa has 14 doors to reduce the time at the stations.

The new Citadis model also used a different engine than the typical one. The new engine is like the New York City Subway system.

"The main difference was the adaptation of the control and the automatic settings," said Declercq.

"I think that would explain some of the troubles we came upon," Declercq said.

Commission lawyer Christine Mainville asking, 'Can you give us some examples? Are you referring to delays or technical problems?"

Declercq responding by saying technically. Mainville pressed for more examples, Declercq saying "like derailments."

Mainville asked Declercq if Alstom had raised concerns about the specifications with the city, Declercq said they did during a July 2012 meeting.

The city’s lawyer pushed back on some of Declercq’s claims, by referring to an Alstom document from 2012, where Alstom wrote, "We are confident in our ability to deliver an optimized system and services based on proven solutions that will meet or exceed the ORLT requirements."

According to the document, Alstom said it was confident the trains would work even in Ottawa’s harsh winters.

"The specific environmental conditions encountered in Ottawa Specific have been carefully accounted for in our proposal. Based on our extensive experience in Northern Europe (regional trains, in Sweden, high speed trains in Finland and currently tramways in Russia). Alstom will adapt certain equipment in the Citadis Dualis in order to provide a safe, reliable vehicle meeting the required operational performances under Ottawa climatic conditions.”

Public hearings continue on Friday and run until July 7.