[lytfyre]

> I see that [...] Canada line under Vancouver chose tunnels over cut and cover because it was cheaper.

Canada Line was mostly Cut-and-Cover - only the bits below downtown and crossing below the water were bored, the bulk of the underground was done cut and cover for cost and speed to make sure it opened for the 2010 olympics.

It was not a popular choice - not really announced before the project was approved, and local businesses along the route took a big hit.

Vancouver's current Broadway Line Extension is being done with TBMs to avoid the impact that the cut and cover canada line segment construction had.

[mitthrowaway2]

It also resulted in a rail line that has to slow down significantly to round screeching curves along the path of the road above.