S--C - Sleeper Crossing (barrow crossing)
CR - 'Catch Rail' (Trap points with a switch only in the outer rail)
HP - Hand-operated points
Lancaster (Castle) station on the West Coast Main Line was well-known, where you could once see steam-hauled expresses roaring past on the 'through' lines. The more modest Midland Railway establishment at Lancaster (Green Ayre) was less famous.
The Midland reached Morecambe by a branch leaving their main line near Skipton, giving access from Leeds and the South. The Midland Railway also promoted its own route to Ireland via a branch from Morecambe to the port of Heysham. The Midland line passed through Lancaster (Green Ayre), crossed the River Lune on an impressive, curving plate girder bridge of nine spans ('Greyhound Bridge', now used by road traffic) and continued to Morecambe (Promenade) station. The London and North Western, of course, had its own station at Morecambe (Euston Road). At Lancaster, a steeply-graded single-line branch less than half a mile long linked the two stations.
I'd first been introduced to Lancaster (Green Ayre) in 1952 (more here), so what I recorded in August 1967 was something of a shock. I found a rather derelict railway with the line towards Skipton singled and the Overhead Line Equipment dismantled. I originally suggested that the single line to Lancaster Castle had been severed, but a correspondent corrected me - apparently the line continued to ship coal to Lancaster Power Station until 1976. I think I misunderstood the dotted lines on the sketch. The fragment of an old Ordnance Survey Map below shows how the single line branch crossed the Down Line (towards Morecambe) at a double slip and made a trailing connection with the Up Line but I think I was unsighted when making my sketch, hence the dotted lines.
My sketch shows Electrification Trains stabled in the Down Sidings. As far as I recall, these were the flat-roofed, black-painted 'Wiring Trains' which proliferated during electrification of the West Coast Main Line.
You can find more Comprehensive track and signalling diagrams of the route in the excellent series of publications from the Signalling Record Society 'British Railways Layout Plans of the 1950's'. Lancaster Green Ayre is included in 'Volume 12: ex-MR Main Line Carlisle to Leeds, associated branches and joint lines' (ISBN: 1 873228 15 5). This publication gives the closure date for both Lancaster Green Ayre box and the next box towards Skipton, Ladies Walk, as 4th June 1967 (just a couple of months before my survey).
There's a Wikipedia Article on Lancaster Green Ayre and I found a Video Presentation which includes a number of historic Science Museum photographs. The impressive station building has even inspired a 2mm/foot scale model (downloadable from modelrailwaybuildings.com)!
[Revised August, 2011]