The start of the First World War saw the hasty construction of a sub branch line to Catterick Camp (now Catterick Garrison). The sub branch separated near Brompton-on-Swale crossing the River Swale via Catterick Railway Bridge, which still stands parallel to the stone bridge that gives the settlement of Catterick Bridge its name. The branch then served the Catterick Garrison.
Closure
The line and its sub branch survived the Beeching cuts of the early 1960s largely thanks to extensive use by the military. The line only survived a few years before succumbing to closure in 1969.