the Signalling Record Society UK (https://www.s-r-s.org.uk/home.php
) and the Signal Box UK (https://www.signalbox.org
) are both good places to start.
The VR, using McKenzie&Holland Pattern, later Westinghouse Brake&Signal, were numbered from left to right.
( For the purposes of this discussion, let us assume the signal box is located adjacent to the Up line. )
The middle group were the points ( black levers ) , to the left, starting at No 1 were the Down Signals on the Up side of the signal box ( red levers ) followed by the Up signals on the Up side of the signal box ( red levers ).
To the right of the middle group of points ( black levers ) were the Down signals on the down side of the signal box ( red levers ), followed by the Up signals on the down side of the signal box ( red levers).
The middle group of points mimicked their location, from left to right, in relation to the signal box ( black levers ). If Facing Point Locks / FPLs were used, then the FPL ( VR , Locking Bar ) lever was usually ( not always ) to the left of the points to which it applied ( blue levers ) and the disc or dwarf signal to the applicable points were usually ( not always ) to the right of the points to which they applied ( red levers ).
At some locations , when the VR upgraded the layout or signals were converted to colour light , one signal lever may operate more than one signal. The particular signal that went to proceed was dependent on the lay of the points to which the signal applied. To maintain the interlocking, the resulting redundant signal lever was painted white over black ( magpie ) and effectively became a route proving lever.
( On power frames whether miniature lever, or slide operated , frequently used one lever or slide to operate multiple signals. This reduced the number of levers required for the particular frame . As interlocking was a combination of mechanical and relay in power frames, the use of magpie levers was not required. )
On the VR , the normal position of signal and point levers is "In" and the reverse position is "out", except for Locking Bars , whose normal position was "out" for locked, and "In" for released. On the NSWGR, the lock bars normal, or locked position was"In", and reverse or unlocked was"out".
Both the VR and the NSWGR manufactured most of their mechanical interlocked frames in house in their own Signal Workshops , Spotswood for the VR.
WARNING signal post numbers and signal box lever numbers WERE NOT the same.
Depending on which British railway prototype you are modelling , the interlocked frame layout may differ from the above , depending on the manufacturer of the original interlocked frame pattern that the railway preferred.
Some British railways DID NOT number their signal posts , the GWR being a case in point.