Was that for shipping purposes, like to prevent damage going in and out of railroad cars? I work for a railroad, and it's standard procedure when spotting "auto rack" train cars at an automotive facility, that the rail cars are always lined up so that the employees unloading the autos or trucks never have to back them out of the train cars. They have fold down ramps so that they can drive from one rail car through another, like a tunnel, until they reach the end car on the track and drive down a portable ramp. So, the way I see it, rear view mirrors aren't critical when driving in or out of a rail car.
When I worked on a local that spotted auto racks at a facility in Kent, Washington, I had to walk the yard tracks where the cars were staged for delivery and look inside each one to see which way the autos were facing, and whether or not the train cars were bi-level or tri-level. There are six tracks in that facility, most tracks held 10 train cars. It was a challenge to try to figure out how to put the cars into those tracks in the most efficient manner, so that the cars on the south end of each track had the autos facing south while the cars at the north end of the track had the autos facing north. Sometimes, you'd fill up a whole track if you had a block of train cars with all of the autos facing in the same direction and they had the same number of levels in them. It didn't matter to the employees because they'd just drive through one train car to the next to get out. Other times, you'd have to do a lot of switching to put blocks of cars together, and maybe you'd only have one south-facing tri-level that you'd hang onto and put it at the south end of a block of north-facing cars. It was kind of fun to solve the puzzle by filling up the tracks while doing the least number of switching moves. You had 4 different types of train cars: north facing bi-level, north facing tri-level (you couldn't combine them), and south facing bi- and tri-level. You could combine blocks of bi- and tri-level cars and north- and south-facing autos in the same track as long as they were "tail light to tail light" as we'd call it.