In the old days, before universal ditch lights, the rear on a road freight unit, such as a GP35, let say, would have only a single headlight bulb rather than two, no class lights nor illuminated number lights at the rear.
These units rarely had a 'pilot' on the rear, thus they were very vulnerable to objects like rocks or deep snow on the track when traveling in reverse.
Ditto an A Unit operating in reverse or a B unit.
Visibility in reverse was awful from an A, especially for a small hoghead.
A Units had all sorts of unpopular characteristics unless going only forward from terminal to terminal, or on a passenger train, and were almost universally loathed once Geeps and other more modern units appeared.
A and B units could pull tonnage, when geared correctly and operating properly.
When running backwards with locomotives without pilots on the rear, care had to be taken.
With an A or B Unit in deep snow, as in feet, it was a good policy to run in with a loaded car to break the way so snow would not go up over rear traction motors and pack in, to later melt at Run 8.
An empty flat or caboose being pushed did not like deep snow either, as too light, and would certainly derail at grade crossings with snow, ice and road sand packed into the flangeways.
The last thing you want to hit at speed with a caboose on a work train or a light flat is something LARGE, like a cow or a moose, even a big bear.
Hitting a big bear was fun on a track motor car. Thankfully, they usually got up an ran.
Company Officers in a highrail Chev Suburban derailed at speed after hitting something on the tracks, sliding down the bank in a cascade of white hard hats, needing an 8-wheel American Locomotive Crane to rescue the vehicle.
An S4 would derail on rarely-used crossings in winter account ice buildup.
Doesn't take much to lift a flange, on anything.
In the good old days, wyes and turntables were necessary, when you wished to turn business cars, Plows, spreaders and equipments having end doors for lading.
Some passenger cars had a 'Front' and would have to be turned.
Occasionally they would turn a TOFC flat so the truck tractor could couple to the trailer on the ramp..