to get the problem with the main road fixed. As well as the hassle to build bridges and tunnels.

Why not implement a “Build Pause” This means, you freeze the actual game.

Now you build everything you want. At the end, you submit your work. Or cancel.

With submit, you only pay for that, what you actually submitted. As long as main road is broken, you cannot submit.

If you run out of money, you always can cancel, and play, where you have been before.

In BuildPause, if a road or track is locked by a train, you should be able to beam it to depot.

[Hard game feature] Implement blocking signals or give signals the feature to stay red, so you are able to block an area, prior to freeze.