To be more clear:

I can bulldoze the underground track module and replace it (with fiddling the camer orientation), but there is no position where bulldozing the ramp track part is possible - so I cannot replace the ramp track with another module.

引用自 GordonDry：

To be more clear:

I can bulldoze the underground track module and replace it (with fiddling the camer orientation), but there is no position where bulldozing the ramp track part is possible - so I cannot replace the ramp track with another module.

Click to the fence over the tunnel portail.

I just made it - it works easy on a 2 track portal with a slight curve - or no curve.
A tight curve can make problems.
A one track portal makes problems, I only can bulldoze the underground track module, but not the ramp track module. There is no point where bulldozing is possible.

引用自 GordonDry：

I just made it - it works easy on a 2 track portal with a slight curve - or no curve.
A tight curve can make problems.
A one track portal makes problems, I only can bulldoze the underground track module, but not the ramp track module. There is no point where bulldozing is possible.

As said, the fences over the track portail is linked to the ramp tracks, there you easily catch them...

At the one track portal there is no fence - as I said there is nothing to click.