I DONT THINK IT MAKES ANY DIFFERENCE - ground side or hot side - as long as the resistor is in the circuit
That being said it POLARITY makes a difference if you want it to light! - The wire itself is color blind.
RE The Aerotrain: (You were being clever), but the Aerotrain was GM’s experiment with Greyhound bus bodies on rails. Apparently removing rubber tires and substituting metal wheels made for an uncomfortable ride.
After touring many railroads, ony two bought . The Rock Island, and somebody else. They were too underpowered for anything except ‘flatlands’.
I think only the 'Rock liked theirs well enough to buy two. Exit GM’s post war passenger car efforts. Consider it a Burlington ‘Zephyr’ in ‘drag’.