There was an article in Model Railroader (I think in the early 1980s), in one of their April issues, on just this subject. The idea was to model more of an industrial-railway type of project than a high-speed one: something to carry goods from a spaceport to industrial sites on a lunar colony. It was a pretty cute idea, with a couple of small models.
There is little need to provide a pressurized tube for the train to run in, or giant train-sized airlocks at the station. All you need are pressurized cars, and an airlock the size of the door of the car at each station. For large bulk loads of raw materials or other things not requiring atmosphere (like girders or electric motors or specialized technological equipment) you can just set it on a flatcar in vacuum, strap it down and you're off. For large containers of vacuum-sensitive goods (shipments of food, for instance) a pressurized modular container could be lifted off of the cars via robot and unloaded via airlock doors, or in the case of things like liquids (water, fuels) the tank could just be connected directly to hoses on the colony structure and the empty tanks returned to the train.
There is gravity on the moon, it is about one-sixth Earth gravity. This means you can carry big, big loads, but momentum is unchanged--braking becomes a real difficulty, as does wheel slippage.
A maglev would be simpler than on Earth, because of the reduced gravity you'd only need one-sixth as much lifting power from the magnets. During the lunar night (14 days long) you'd have no problem keeping superconducting magnets cool, but during the day heat would become a problem. And, as mentioned above, you wouldn't have to worry about aerodynamic streamlining.
How to model a maglev? Build a model maglev! It would cost a lot in rare-earth magnets and electromagnet assemblies, but it should be possible to build a working maglev model and run around a train. Or you could just put hidden wheels under it!
Weathering would still be an issue: there's plenty of lunar dust, and human activities would kick up that dust and get it into things. The color scheme would be pretty monochromatic--blacks, grays and white.
Here's a link you might find interesting:
Micro Layout Design Gallery
(Scroll down to "Copernichaum XXIV.")