It's only a 240-metre long section of unused track near Bayview station, but it has landed the City of Ottawa in hot water with the federal regulators of railway lines, and has a private proponent for commuter rail warning that fixing the mistake could cost the city up to $25 million.

It's also left the city councillor for the area wanting answers from the city's legal team.

"How did we get to this point, where it looks to me like a key permission from the government to move ahead with construction was somehow missed?" asked Kitchissippi councillor Jeff Leiper on Thursday.

The section of track in question runs from the Bayview O-Train station to the Prince of Wales Bridge on the shore of the Ottawa River. It's been unused for years and sits right along land being developed for the city's new Bayview light-rail station.

According to the Canadian Transportation Agency — the federal regulator of railway lines — city confirmed in February that part of the track was removed to make way for a west side entrance to the Bayview LRT station.

Making matters worse, the CTA says information it's received suggests the city has built permanent structures on top of the old railway line. Neither action is allowed without first notifying the CTA, which the agency says didn't happen.

Bayview station LRT construction

The city is building the station as part of the multi-billion dollar light rail transit system, one expected to be running in 2018. (Giacomo Panico/CBC)

City ordered to explain actions

On Wednesday, the CTA told the city it has until June 28, 2017 to show cause, explaining how the city's actions weren't a breach of duty.

In an email Thursday, city solicitor Rick O'Connor said staff are reviewing the matter and will prepare a response to the CTA in a timely manner.

"As this is a regulatory hearing process, the City will not offer further comments at this time," wrote O'Connor.

In addition to his own question to the city solicitor, Leiper said he'll be asking city planning staff to clarify the long-term plan for the Prince of Wales bridge, which he sees one day as an important commuter rail, cycling and pedestrian connection between Ottawa and Gatineau.

Jeff Leiper

Kitchissippi councillor Jeff Leiper said Thursday he wants the city's legal to explain how the section of railway line was removed without first getting the approval of the Canadian Transportation Authority. (Giacomo Panico/CBC)

In March, city council directed Ottawa mayor Jim Watson to begin formal discussions with the mayor of Gatineau on how to get the bridge back into operation.

"I'm confident that the city is going to be able to go back to the agency, demonstrate that it has a plan for putting rail back on the bridge, and that the engineering is possible," said Leiper.

Undoing move may be expensive

The CTA initiated its investigation after receiving information from the Moose Consortium, a private venture aiming to run commuter rail service in the Ottawa and Outaouais region.

Moose's director general, Joseph Potvin, has long maintained his desire to run commuter trains across the Prince of Wales Bridge.

"The existence of a railway connecting the two halves of the National Capital Region is critical," said Potvin on Thursday.

According to Potvin, undoing the city's move will be expensive, given the permanent obstructions the city has now built on the old railway line. 

Prince of Wales Bridge

The Prince of Wales Bridge is the only railway line still connecting Ottawa and Gatineau. (Giacomo Panico/CBC)

"There's only one thing as far as we're concerned that can happen," said Potvin. "The agency must order the city to fund the prompt re-creation of the railway connection, which is about a $20 million to $25 million commitment for Ottawa taxpayers that should not have had to be spent."

If there's a bright side to this incident said Leiper, it's that it brings attention to the plight of the old Prince of Wales Bridge.

"There is no funded plan right now, but there is momentum and I think this particular decision on the part of the agency will keep the spotlight on us and makes sure that that momentum continues," said Leiper.

"If anything, I think it again puts the long-term future of the bridge firmly in the spotlight."