The summit is the highest point on the Caledonian Railway Main Line north of the border (built by the Caledonian Railway and opened on 15 February 1848), it is located 52 miles (83 km) south of Glasgow Central and 349 miles (558 km) north of London Euston stations.

[3] It is 62 miles (100 km) north of the second highest point on the WCML - Shap Summit in Cumbria.

The northbound climb has a 15 miles (24 km) ascent, with gradients of up to 1 in 69 (1 foot of rising or falling gradient for every 69 feet of distance) which made it a notoriously severe climb in the days of steam locomotives, which frequently required banking assistance to get their trains up the incline.

There was an engine shed at Beattock which had banking locomotives on standby twenty-four hours per day to minimise train delays.

The severity of the climb to the summit is referenced in W. H. Auden's poem Night Mail, written in 1936 for the G.P.O.