Editing Double switching (section)

=== Clapham ===
The [[Clapham Junction rail crash]] of 1988 was caused in part by the lack of double switching (known as "double cutting" in the British railway industry).<ref>{{cite book |year=1989 |title=Investigation of the Clapham Junction Railway Accident |publisher=[[Department of Transport]] |last=Hidden |first=Anthony |isbn=0-10-108202-9 |url=http://www.railwaysarchive.co.uk/documents/DoT_Hidden001.pdf |accessdate=7 September 2012 |page=51}}</ref> The signal relay in question was switched only on the hot side, while the return current came back on an unswitched wire. A loose wire bypassed the contacts by which the train detection relays switched the signal, allowing the signal to show green when in fact there was a stationary [[train]] ahead. 35 people were killed in the resultant collision.