I need to build an underground tram system.

[Green_Elite_Cab]

I think subway trains would do, and, if they're not available, then normal HO or O scale would do.

There is a third option. Have you considered 3D printing?

All that is necessary is a good computer generated 3D model, and the 3D printer will make it physically. It cost significantly less than buying even a single subway set to get a handful of shells, and you can design them to fit over existing, cheaper model railroad locomotive drives.

This way, you can get something that looks futuristic that is cheaper than buying a model that most people will recognize as a New York City subway.

You can send your 3D model here and they will make it in plastic. You can also sell you design on the internets, so that others can buy it and you get some of the profits.

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