Utrecht – The NS is bringing out two monumental trains for Open Monument Day. The Mat ’46 and the Mat ’54 from the Railway Museum will be coupled together on Saturday 14 September to travel as one train a few times from Utrecht Maliebaan station to Den Dolder, Bilthoven and Amersfoort Centraal. Passengers will be accompanied on board by staff in historical uniforms. “These are historical trains, so there is no air conditioning,” according to the NS.