Here's a Lionel No. 66 Semaphore (1915-1926) which came as one of the accessories on my 199 Scenic Railway and stands 14" tall. It is operated manually with the red upper arm alternating between a red and green celluloid disc over the lamp and the lower green arm which alternates between green and amber. The arms operate independently.
It was intended (in this case) to sit alongside a single set of rails on a curve leading to a signal crossing. It offers no control over the track power and the lamps are always lit.
My question is how would a model engineer operate this accessory so as to simulate a prototypical signal in operation ? What would be the appropriate position of the arms for a train being halted vs a train with the go ahead ? Perhaps it was simply a toy and I'm overthinking it but it seems Lionel would always try and incorporate and promote some measure of realism with their trackside accessories.
