The naming of tracks is by individual railraod rules or useage, local practice or sometimes, it can just be lost in history. In my youth, I worked as a yard clerk for the Elgin, Joliet and Eastern Railroad in Chicago Heights, IL. We had a four track yard bisected by two main tracks just outside the depot where I worked. The tracks, were named, from south to north, back track, long track, eastward main, westward main, No. 1 track and team track. Don't act me why. Nobody else knew how the tracks got their names. There was another yard in town, the Hill Yard, where the tracks were numbered, from north to south, No. 1 through 5, which, of course, at least makes sense.