I am not positive, but I believe this is a crossing point for each railroad, near Boston Bar, in the Fraser River Valley.

This is actually all CP rail that is visible, at a place called Cisco. I have travelled the Trans-Canada highway many times through the canyon, and have always found it amusing that one can see either corporation's trains on both sides of the canyon seemingly willy-nilly, but it must be that there is a direction consistently when sharing one side or the other.