Belgian railway stamps are listed in the Belgian specialized catalogue. The Dutch ones are not in the NvPH catalogue. As a matter of fact, I have never seen a listing of them, nor have I seen even one of these stamps in larger collections over here.
The most detailed listing of these stamps is in the book "Spoor en Post in Nederland" (published by the Nederlands Spoorwegmuseum, Utrecht 1979). They are also listed in less detail in "Benelux Revenues" by Barefoot.
On line, they are listed on the Netherlands Revenue site of Leo Bakx: Revenues
Thanks Jan, i searched ebay and they had some for sale. But what could be the reason for the imbalance between the Belgian and the Netherlands? They both had to be using trains for freight at that time(`1930s-1970s)
I don't know the reason for the imbalance. I like the design and I have accumulated them when I run across them. Even then, I don't see them very often.
Really interesting website. Thank you for sharing it with us. I might end up collecting these railway stamps too, there aren't that many of them, I noticed.