There were several types of railway stamps in use in the Netherlands. From 1914 till during the Second World War (1944) there were railway stamps mainly used for freight, but these could also used for railway express letters. In those cases the railway stamp for the express service by the railway company (10c) had to be glued on the back side of the cover.
The envelope had to be fully franked according to the rate of PTT on the top. The stamps were cancelled by the special boxed postmarks of the railway station where the letter was presented, in this case (1) Lochem in 1934.
In 1946 ‘treinbriefzegels’ (railway letter stamps) were issued. This lasted till 1979, when it stopped completely. Theses stamps were no longer meant for freight letters, but for normal letters sent by express per train and delivered by the post. Very often this system was used by newspapers, journalists, photographers and companies, but it was still possible to use the system for express by the public (2). Also now , the letter had to be fully franked according to the rate of PTT.
Not very common you will find those railway express letters without additional franking, like in this case (3, 1967) a letter from the governmental communication department which could send free of postage through state owned PTT. For the state owned railway company NS one had to pay however for the express.
In 1970 the service became already limited (4+5).