I have family connections with that bridge. Sturdy metal bars under it cross over the river Skerne. My mother fell from them and broke her ankle during the 1914-1918 war, but this did not deter me from swinging from them during the 1930s.
However, the trains thundering overhead were speeding north to Newcastle and Edinburgh, as they still do. The Stockton-Darlington line went nowhere near the Skerne Bridge, but forked east from Darlington, past my grandfather's field to cross a bridge over Haughton Road, long since demolished. That bridge was not available to illustrate on the river and artistic licence came into play.
WILLIAM L ATKINSON