Colin Ryder provides the caption "
42449 of Carnforth (24L) and 45512 ‘Bunsen’ of Carlisle Upperby (12B) have just passed the Grayrigg signal box, an ex-LNWR type erected originally in 1926 and known for leaning over backwards because it was built on soft peat. It closed in April 1973 when Carlisle power signal box took over all functions.

This stretch of line is of historical significance: it was the realisation by the engineer-surveyor George Larmer in the spring of 1840 that this ‘pass’ between Grayrigg Pike and Lambrigg Fell offered a practical route through the line of hills running south to north to reach the Upper Lune Valley that ended years of wrangling over what was the best way to reach Carlisle.

Within a few hundred yards the train will enter a series of curves (see the photo of 45571 on this website) that returns the line to a south-to-north alignment and so pass through the Lune Gorge and reach Tebay before ascending Shap Bank.

The line on the right is the down loop. The photo is taken from the headshunt to the up loop which passed behind the original up platform of the station (see the photo of 42299). "