I was looking some more into to the live map idea of mainline train movements similar to openseamap's: and I found this useful list of all the route numbers:-
RouteCode From Open Rail Data Wiki
Network Rail divide the network up in to a set of routes, identified with a code, e.g. MD101. These codes are used in the Sectional Appendix.
A list of route codes from the Sectional Appendix - correct as of 12th June 2012, is available.
As I get time I am still looking to be annoting these to OSM with the help of NESA pdf ed diagrams. The list of things hoping to do is still larger than the time available but the finite nature means that I'll get there eventually.
I found out how to make relationships work with some of the editors (I don't think id will work on [my] today's computer). So I will try and do them in a grand relationship. NESA also holds the abrviated official name of each "road"/track that is on some public faceing signs at places like bridges so I want to do these at the same time like I did nr padington.
going into the station the editor became a confusing bunch of parrell lines that began not fit easily with the NESA Diagram and using bing beneath just made it worse to comprehend! so staed near a flyover instead. earlier work is nr didcot jcn.