Hi I have experimented with the trf file and moved the map someway towards alignment. Though it is fiddly and a bit of guess work. Is is possible to rotate the map? Can I suggest that a future enhancement would be a mouse drag-able map.
I live in Northern Ireland and the GB OS website does not cover NI. The local OS want payment for maps of suitable scale. I went to the local city library to find the old maps. I was surprised that they allowed me to photo it ( but not photocopy ) My photos only cover the local area around the railway track and the grid lines are not consistent from one photo to the next. The maps were held in a large ledger so it was difficult to get them flat. Also I manually tried to keep the height I was photographing from consistent. A possible source of error was at the crease of the ledger.
I use Google Earth to get the co ordinates of the references on the map. A few of the road junctions or field edges have changed but there is enough to use. Perhaps in the passing 70 years some of the reference points are not what they were. I can still see the outline of large lengths of the original railway on Google Earth. There is a lot of cloud over parts which is going to make it difficult to work with. Is there another system I could use that still gives me co ordinates to reference my raster maps?
I have experimented with tiles. The wire mesh in Trainz route seems very fine and obscures the detail on the tile. Of course the tile is flat and the land is contoured so it takes a bit of fiddling to move the tile up and down to be able to read the layout on the tile.