This is an old revision of the document!
The subway wagon is one of the first models made for advtrains. It is loosely based on a european metro/U-bahn train, like one from Berlin or another European city.
There are a few derivatives of the subway wagon in different colours and so on. It is probably the most ubiqitious train in minetest.
If the subway wagon has a line number property set, and that number is between 1 and 10, it will apply a specific texture to both ends of the wagon to indicate its line number. If that number is between 11 and 99, code will generate the number and a colour background to go with it. If the line number is “X”, it will display a big red X, which is usually to indicate the train is out of service. This is the only train with such features known so far.