This was my first project using Houdini. I was still learning Houdini and was stuck with using the apprentice license which couldn't take advantage of exporting HDAs to unreal. So I made a blueprint in UE4 to cobble together the different cart parts in engine. All the parts themselves are modeled procedurally in Houdini, and textured in photoshop and substance painter.
Got the idea for this project when re-watching the 1985 movie Night on the Galactic Railroad. The film has tons of beautiful scenery, but half the movie takes place in this train car. Remaking the train car in 3d was tricky because no two reference shots inside the car precisely agree on the proportion, shape, and placement of props. Hence why I've made it procedural, so I can change those kind of details on a whim.