Tram roof

 

The tram roof makes use of a 3D printed interior skelton, on to which the builder sticks a piece of plastic. The holes for safety valve and chimney are pre-cut, which makes me hope I didn't make the replacement boiler any longer than I should. 

1mm thick plastic is quite strong, so I stuck it through the rollers to put a curve on. The supports are also strong, but it makes sense to reduce the conflict between the two. 

Removing the 3D print supports was a fiddly job. Lots of triming with some flush cutters and sanding. You could probably skip that step, and I wasn't entirely sure I needed to do it, but I'm glad I did.