I haven't played this route for a long time, but after driving from Field to Lake Louise I noticed several large areas where the terrain beneath the track has lowered, leaving the track noticeably floating in the air. This terrain may have been modified with the terrain snapping tool, so maybe a change to this scripting broke some of the terrain. I found multiple instances of this between Field and Lake Louise, and there are likely many more along the rest of the route. The two locations shown are between the two spiral tunnels (top) and about a mile west of Lake Louise (bottom).
If you turn up the scenery density that will solve the issue, you will also find along the route what appear to be floating signals this will also fix that.
After using the external rear camera view All cameras go into and stay in bombardier (looking down) mode, except the cab view.