The Harmelen train disaster was the worst railway accident in the history of The Netherlands. Harmelen, near Woerden, is the location of a railway junction where a branch to Amsterdam leaves the Rotterdam to Utrecht line. It is common at high-speed junctions to avoid the use of diamond crossings wherever possible — instead a ladder crossing is employed where trains destined for the branch line cross over to the track normally employed for trains travelling in the opposite direction for a short distance before taking the branch line.
Shortly before 9.20 a.m. on Monday, 8 January 1962, a foggy day, a Rotterdam to Amsterdam train consisting of electric multiple unit sets 700 and 297 was authorised to carry out this manoeuvre, protected by a red signal to stop trains approaching from Utrecht. The EMU was travelling at approximately 75 km/h (47 mph). Simultaneously, an express train from Utrecht to Rotterdam, hauled by electric locomotive 1131, was approaching at about 100 km/h (62 mph). Perhaps because of the foggy weather, the driver of the train from Utrecht missed the warning yellow signal and applied the emergency brake when he saw the red signal protecting the junction, far too late to prevent a near head-on collision between the two trains. Six coaches of the Amsterdam train and three on the express train were destroyed. Of approximately 500 people aboard the trains, 93 lost their lives, including the drivers of both trains.