I dont think that Train Order Boards were ever called semaphores. I do know that there were a couple of different types of Train Order Boards which include Upper Quadrant and Lower Quaderant. As the name implies Upper went up for no orders and Lower were all the way down for no orders.
I have seen some video of a train coming down out of Alamosa and when it reached on of the stations the semaphore/order board was lowered. I would have to go back and see where it was and what type of siginal it was.
John V