Geograph - photograph every grid square

The banner signal was invented by W R Sykes & Co around 1900 as electrical operation of signalling was beginning to become a practicality.
The "arm" of the signal rotated on an opaque disc in an enclosed glass case, allowing lightweight operation in a clean environment.
W R Sykes Interlocking Signal Co was established by William Robert Sykes (c1840-1917) in 1862 and in 1899 incorporated as a limited company. It became a Public company in 1907.
W R Sykes was the inventor of the lock-and-block system of railway signalling.