Harmelen, in the central Netherlands, is the location of a railway junction where a branch to Amsterdam leaves the Rotterdam to Utrecht line.

Shortly before 9.20 a.m. on Monday, 8 January 1962, a foggy day, a Rotterdam to Amsterdam local-train consisting of electric multiple unit Mat '46 [nl] sets 700 and 297 was authorised to carry out this manoeuvre, protected by a red signal to stop trains approaching from Utrecht.

Simultaneously, an express train from Leeuwarden to Rotterdam, hauled by electric locomotive 1131, was approaching at 107 km/h (67 mph).

On 8 January 2012, Pieter van Vollenhoven unveiled a memorial for the victims of the disaster, which on that day had taken place exactly 50 years earlier.

A red stone plinth, bearing a body that represents the victims, is placed in the middle in front of the two slabs.