@noleli it sure looks a lot like the electrical schematic symbol for a Single Pole Dual Throw (SPDT) switch -- which yes, has a function a lot like the railroad switch -- so same idea.
@nickchuckwalter @noleli That's (β) famously the "Looped Square" symbol used as a road sign for places of interest in Nordic countries, Susan Kare borrowed it for use on Apple keyboards
https://en.wikipedia.org/wiki/Looped_square#Modern_use
Interestingly, this is recorded history, whereas I'm not aware of an authorative source regarding whether the "option" key (β₯) was designed after railroad tracks, or a microswitch, or something else