Old Rail Bridge (Short Multi)

The cache, a camo-taped preform tube, is hidden not far from this fine old stone rail bridge - a remnant of a historic closed 'royal' line - on Back Beck Lane, a lovely narrow shady road running from the top of Sugar Hill across the north-east corner of Addingham.
To reach the cache: from Addingham Main Street @ N 53 56.672 W 1 53.167 take Chapel Street heading north to join Back Beck Lane. Parking (at the given coordinates) is available at a small lay-by by the bridge) with road access only possible from the west side . . .
Alternative quirky route: from Addingham Main Street @ N 53 56.672 W 1 53.055 take the (very) narrow Sugar Hill which twists tightly between the old houses up to the T-junction with Back Beck Lane and head right (east) to the bridge.
Step 1: from the posted coordinates (and parking spot) head for the blue plaque on the east wall of the bridge. On this, you will learn that:
The bridge number is AA where A is the value required.
It carried passengers and freight for BC years.
The plaque was unveiled on the D April 2018
Around the corner from this plaque, under the bridge is an old-style white-painted stenciled bridge identifier (see here and here) with 6 letters (denoting the responsible government body and the line) and 2 figures (the bridge number) separated by a forward slash.
There are E lower-case letters (ie. not capitals) on this marking
Step 2: the number on the lamp post @ the eastern end of the parking spot is F
The cache is hidden at:
N 53 56.BA(C+E) W 1 52.DFA

Some background history (part 1):
The Midland Railway was an enterprising railway company. It had already constructed the line, completed in 1876, linking Settle with Carlisle over some of the most difficult terrain imaginable, including the famous 'long drag' with its many tunnels and viaducts.
It then focused on an 11-mile/ 18 km Ilkley to Skipton line, an extension of the former Otley and Ilkley Joint Railway. There had been proposals, agitations and abortive Bills of Parliament for several years before the scheme received Royal Assent in July 1883.
In April 1885, a contract was awarded to Mousley & Co. of Bristol and work began in June. The line was completed to Bolton Abbey by summer 1888 and the remainder opened in October.

The first through ticket was purchased by Welbury Kendall, a Skipton timber merchant.
The new railway left the already established Ilkley Station, via a series of bridges spanning the genteel spa town and the flood plain of the River Wharfe, making its first station stop in the village of Addingham.
Beyond Addingham, the line climbed and passed over the impressive and secluded Lob Ghyll viaduct (see GC7YACN WRW#32 If you go down to the woods), now invisible due to tree growth, and entered Bolton Abbey station from where the railway continued climbing up to the watershed between the Wharfedale and Airedale valleys.
Bolton Abbey Station has long had a royal connection, being the nearest railhead for the Duke of Devonshire’s Bolton Hall, with a number of reigning monarchs visiting the Duke or simply enjoying the grouse shooting on the nearby estate moorland.
King Edward VII visited in 1902 for the grouse shooting, arriving by the Midland Railway’s Royal Train whilst the LMS Royal Train conveyed King George V in August 1922, before he moved on to Balmoral a week later.

During WW2 an air raid shelter was constructed in the embankment adjacent to Bolton Abbey Station and this was regally appointed for the use of the Royal party should the need arise. The last known visit of the Royal Train was in October 1947.
The final intermediate station was Embsay, from where the railway descended to its own platforms in Skipton Station where it rejoined the main line along the Aire valley. Continues with GC8VKN7 Old Rail Line (Offset Multi) . . .