No picture to add, but, we had a number of them in Roper. As has been mentioned, a rubber, or variable switch is forced to the direction of travel by the wheels. Unlike a spring switch, when it is forced over, the mechanism in the switch stand itself rotates, including the handle, and stays in that position. It was particularly important to always "hook" the hook..as the handle would fly up and strike you if you were near enough as it rotated! At Roper we had them on the main switch leads with most the yard ladders rigid. This way an engine or train coming from a yard track had only to line their track..and then could run thru any other lead switches. This was a great aid for a yard that had more than one engine working the same end. Our wye had them, as well. They could be easily recognized if they were the tall ones...they were the ones with the round bodies...the ground throws also had a half round cover on them. They were supposed to be marked with a "V"...but that didn't happen in Roper until just Before the UP showed up and took them all out.