One of the comments Tom Pearce had on my PRR FF2 variant was that the headlight should not oscillate. When I was building the Y-1 model, the few photos that were available seemed to show a Mars R-250 oscillating headlight. Upon further inspection of the photos I became convinced that Tom was right, and on the FF2 model the headlight does not oscillate.
You can easily disable headlight oscillation on your Y-1s if you want. Navigate to the folder Assets\G-TraX\Cascadian\RailVehicles\Electric\Y-1\Default\Locomotive and find the file mars.ban, which is the animation file. Either delete the file entirely or rename it to something like xmars.ban in case you'll want to restore the oscillation some day. The animation will cease and the headlight will operate in the normal way.