Worst accidents The worst accident was the Quintinshill rail disaster in Scotland in 1915 with 226 dead and 246 injured. Second worst, and the worst in England, was the 1952 Harrow and Wealdstone rail crash, which killed 112 people and injured 340.

The worst rail disaster in British history is the Quintinshill rail disaster, which occurred on May 22, 1915, near Gretna Green, Scotland. The high-fidelity catastrophe involved a five-train collision that resulted in the deaths of an estimated 226 people, the majority of whom were soldiers from the 1/7th Battalion, Royal Scots, heading to the Gallipoli campaign. The crash was caused by a series of critical signal errors; two signalmen had "parked" a local train on the main line to allow an express to pass but forgot to protect it. A troop train then slammed into the stationary local, and minutes later, a northbound express crashed into the wreckage. The high death toll was exacerbated by the wooden carriages of the troop train catching fire, fueled by gas lighting systems and the soldiers' ammunition. The disaster remains a foundational case study in British railway safety, leading to the eventual mandatory implementation of "track circuits" and more rigorous communication protocols between signal boxes to prevent human error from causing such a devastating loss of life.