That's a very good question, Wayne.
The Phillips semaphore was not on the platform. Rather, it was located midway between the station and the covered bridge, just south of the Main Street crossing. (See attached map.)
Unfortunately, I've never seen a clear photo of the signal so I can only guess as to the mechanism, but I've always assumed it was a pretty simple home-made affair, probably all wood.
It's one of those things we definitely know existed because it's specifically mentioned in the SR&RL rule book, but there are more questions than answers about it, unfortunately.
It was the only semaphore on the Two-Footers.