The Lynbrook shot of which I speak is NOT the one you saw in the calendar. Mine is a black and white shot and, as far as I know, never before published anywhere (one of the features for which I strive in my books!).
Signals are removed for many reasons: They can be relocated in one direction or another. Tracks for which they are designated are no longer in use. Temporary tracks are placed in service and have new signals to control their use. An interlocking is rebuilt and the signals repositioned, etc., etc., etc. (as Yul Brynner said in "The King and I.")
There can be any number of reasons why a signal can be there for a time and then removed. In the image below at the junction of the Main Line with the Belmont Park Race Track spur, we have such a situation:
The shot was taken in 1968. The near bridge is void of signals and had been since 1957 (!!!) when the far bridge was placed in service with position lights, replacing the near bridge which had semaphore-arm signals. This view is eastward. The brick building is a circuit breaker house.
Dave Keller