View from Up platform looking west showing the power-operated signal box. The lines to the left are for Preston and those on the right for Blackburn. The third side of the triangle passes behind the signal-box. Photo: Dr J W F ("Ian") Scrimgeour 22/7/56
eneral interior of Westinghouse EP frame and block instruments. Installed in 1904, this box works the west end of Bolton station and its triangular junction. Block working is to Bolton East (Up side and Down Main lines), Bolton Down (Down Platform Loop), Bullfield East (Preston lines) and Bradshawgate (Hellifield line) (from information on photo) Photo: Dr J W F ("Ian") Scrimgeour 22/7/56
A further general interior view. The L&Y block instruments in the background are for absolute block working to Bullfield East (2) and Bradshawgate. The instruments in the foreground are Tyers Permissive for station working to the East and Down boxes.Photo: Dr J W F ("Ian") Scrimgeour 22/7/56
The block instruments are also interesting. Look carefully at the two double line permissives in the first picture. The one nearest the camera has a 'face' much like the ones at the far end of the shelf, and also like instruments from ex-GCR territory (see Woodhouse Junction at main signal box site). The other one has a different style - separated segments for TOL and LC - and also a thicker base, i.e. more like the LYR absolute instrument nearest the camera. I have seen a single needle permissive version of this 'LYR style' too, which was said to be from Bolton. So I wonder if they were made specially for the L+Y (or were even made by the L+Y, although I have no proof of the this). It is also interesting to see 'standard' Tyers instruments at Bolton.
The frame itself is at the NRM but has not been reassembled as far as I'm aware. The lower quadrant signal just visible next to the box is at Llanuwchllyn on the Bala Lake Railway, having reverted back to mechanical operation.
Essentially the signals would be observed visually but the indication, or check, lock on the lever would prevent the lever being replaced to normal unless the signal was on. There would be no positive off indication.
from a 1963 plan I there were large numbers of push/pull and selected signals (some were both!) there were 123 signalling-type functions from 45 levers