What are Single & Double compartments on overnight trains?
Single compartments are 1st Class sleepers. Doubles can be 1st Class or 2nd Class, depending on the country. The amenities offered are basically the same, and include a lock on the door, an electrical outlet, a washbasin, and a luggage storage area. Single compartments have one berth, or bunk; Doubles have two berths (normally 1 upper and 1 lower).