This was taken from the northern bank of the River Lune below Halton Green, along a little-known footpath.

The railway viaduct was built in 1882, with wrought iron arches and latticework on masonry piers supporting a wooden deck. That's the weak point: though British Rail retimbered the bridge in 1956, in March 2004 a hole appeared in the deck and the viaduct was closed for restoration. It's Grade II Listed, so work took over a year and cost £880,000.
That may seem a lot for a disused railway bridge, but as part of Lancaster's Millennium Park (aka the Lune Cycleway), at the Crook O'Lune, a popular tourist spot, it receives about 250,000 visitors per year.