Agreed there a lot of pre-cancels. The attached images show my three pages of them
Hi Tony, there are indeed a lot of precancels but the three pages you posted are not precancels but Parcel Post stamps.
I think these are very fascinating - one can look at them in a lot of ways. Many people look at all the offices they are cancelled at. Belgium had a very dense network of railways, and it is possible to link the stamps and cancellations to specific line
There are a few threads on here and no doubt elsewhere that are worth looking up