There’s an interesting tram/train ride in Pittsburgh called the Duquesne Incline. It runs off of a single barrel roller pulling steel cables attached to train cars that run parallel to the ground while also being hoisted up the side of a hill. It’s quite a sight to see and one that definitely reminds me of Angel’s Flight here in Los Angeles.

Anyway, one interesting note: The teeth on the giant cog wheel that pulls the cars up the hill are made of rock maple wood. Not steel like you would imagine of a gear of that size.