I have one on my wall, but found only two slightly better maps of mainlines on on the web - but, unlike your EuRailPass map, they at least show Eastern Europe and the routes rather than straight lines. (Here is the first [very big!], below the second, click image for large version.)

However, Trainspotting Bükkes has a nice and growing set of railway country maps and maps of some 'dense' regions that show all lines in each country/region, now only the Baltics, Belarus, Russia and the Caucasus still missing. (Incidentally, they were made by a French-Russian.)

_{*Lunatic*, n.
One whose delusions are out of fashion.}