Steam Whistle Brewing has offered to invest $10 million in a museum at the CPR John Street Roundhouse in order to derail a plan that would see a Leon's furniture store overtake the property.

"In the building now are a bunch of old rail artifacts and we would like to restore those and have this whole building opened to the public," Cam Heaps, President of Steam Whistle Brewing told CTV News Monday.

Steam Whistle, which has been located in the building for the past seven years, is proposing to quadruple the size of the rail museum to 30,000 square feet.

The building is one of the last standing brick railway houses in the country.

Leon's Furniture has signed a lease agreement with the developers, filed it with the city and is ready to move ahead with plans for a contemporary store geared toward the waterfront condo market.

The furniture retailer has promised to dedicate a small centre portion of the space to a rail museum and will maintain the historic character of the building.

Heaps said the area is a tourist hot spot because of its close proximity to the CN Tower and the Rogers' Centre and that a furniture store would be inappropriate for the region.

Ten years ago, the city agreed to preserve the Roundhouse as a rail history museum.

The city has since outsourced its decision-making to a private developer, who has scaled back the museum project to just 7,500 square feet at the back of the building to accommodate its proposed new tenant.

Steam Whistle Brewing is proposing a fully operational turntable to move locomotives into and out of the Roundhouse.

The museum would exhibit as many as ten engines and cars, with educational displays about the history of Canada's national railway.

Councillor Adam Vaughan has enlisted the help of former mayor David Crombie, Toronto Blue Jays president and former Metro chairman Paul Godfrey to ensure Leon's does not set up shop in the space.

Vaughan, along with other members of the Friends of the Roundhouse, is urging city council to rethink its decision.

"We have a responsibility to animate our historic buildings in culturally sensitive ways. It's not Leon's that is the problem, in some ways Steam Whistle is part of the problem. We have to stop commodifying our history," Vaughan told CTV News on Monday.

With a report from CTV's John Musselman