Vancouver has launched a constitutional challenge to block Canadian Pacific from reactivating a railway line along the Arbutus Corridor.

The city is also seeking permanent injunctions to prevent CP from demolishing any of the community gardens it hasn’t already cleared away from the 11-kilometre corridor, Mayor Gregor Robertson announced Friday.

“Our interest is in protecting that corridor as a greenway,” Robertson told a press conference outside City Hall. “We feel there is no further option at this point other than to take some legal action.”

The injunctions would also bar CP from starting any construction or spraying herbicides on the property.

The city filed its challenge in B.C. Supreme Court Friday morning, three weeks after CP walked away from negotiations over the corridor’s future.

Robertson said the city offered to buy the land for “fair market value,” and even to have it independently appraised, but was rebuffed by the railway.

“We won’t be bullied on the Arbutus Corridor,” he said. “We won’t overpay by tens of millions of dollars as they’re suggesting we do.”

The sticking point in negotiations has been the value of the land, which CP argues should be appraised based on the value of adjoining properties.

That would make the Arbutus Corridor worth at around $400 million, according to the railway.

CP said it offered to sell the land for a fraction of that, but hasn’t publicly released the figure. Robertson said it’s in the neighbourhood of $100 million.

The city has maintained it only wants to use the corridor as a greenway and potential transit corridor, and insists that should factor into the sale price.

Residents living along the corridor have tended gardens on the unused property for years, but were handed notices over the summer warning them to remove all property by July 31.

Crews started plowing through gardens, benches and sheds in August, but work was temporarily suspended until negotiations with the city broke down in mid-September.