Abstract: A module structure toilet room (1) is disclosed. The toilet room is built from module parts (49-52) containing functional units in the form of a toilet bowl (8), a fecal tank (7), a heat exchanger (61), a water tank (13), etc. Each module has connection conduits with quick release couplings for interconnecting the functional units and means for direct mounting of the module parts on the bearing structure of the train wagon. The module parts also have fixed/releasable coupling means (78) for mounting the fitting elements in the form of wall coverings and the like.As the functional units may be built and tested before the final mounting in the train wagon (2), considerable savings may be obtained in the mounting time of the train wagon. Furthermore, the module structure enables the toilet room 1 to be used in several different types of train wagons (2). Furthermore, servicing may be accomplished easily as the functional units are built together and may easily be jointly replaced.