The primary source for railroads is an Atlas published in 1915 by the American Geographic Institute of Indianapolis, Indiana. It was prepared when the railroads were at their prime, so it shows a number of proposed routes as well as many that were soon to be abandoned as unprofitable.
The 1972 USGS Geological Survey map was used to determine which of the old railroads were still in operation in 1972.
The 1986 edition of the HISTORICAL ATLAS OF OKLAHOMA by Morris, Goins, and McReynolds was used to match some acronyms with names and predecessors with successors.
Some clues were picked up from John Kirk's website. If your primary interest is in railroads rather than places your ancestors lived, his site contains a wealth of information.
The primary source for electric railways is the book WHEN OKLAHOMA TOOK THE TROLLEY, by Chandler & Maguire.