Thank-you for the feedback! The building mechanic was something we experimented with throughout, and it went through a few iterations.
The first version was drag-and-drop, before we realised that would overcomplicate things when we didn't have loads of time (so we dropped it 😁).
The second version didn't have the 'rail dock' at the bottom of the screen, but instead each placement had its own little UI where you could place/switch piece/undo, but we found cycling through the different pieces to be more frustrating than just having them on dedicated controls.
The version that's in the game changed a bit when we switched up the scoring from "as a piece is placed" to "as a route is completed" - previously, only the current piece would appear as a ghost rail, but subsequently the whole route would appear ghostly as it hadn't been scored yet.
I think we could have communicated the spot you were placing (versus the rest of the route) a little better - maybe it could fade in and out? Or have a box around it to show current selection? There are a few options, but you're definitely right that it could be more clear.
Anyway, thanks so much for playing!