Southern region track standards interim note for vertical longitudinal profile (TM-FT-063)

The derailment of a small number of mineral wagons on the Southern Region with no readily definable cause, led to the imposition on 30 October 1975 of a 35 mile/h (56 km/h) speed restriction on all trains carrying such vehicles, over some 1 200 miles (1 900 km) of route.