Derailers & depot protection

A derailer is a device clamped or mounted on a rail to stop an unauthorised or runaway movement by deliberately derailing it before it reaches a running line, a work zone or staff — the everyday protection mechanism of depots, sidings and engineering worksites. People searching for 'the derailer standard' deserve a plain answer: there is none. No dedicated EN, ISO or UIC document governs derailers or depot protection as such. The space is filled three ways. First, where the same protective function is engineered as point-work — trap points and catch points diverting a movement into a dead end or sand drag — the hardware is ordinary switch engineering under the EN 13232 series for switches and crossings. Second, national rulebooks decide when and where protection is required: in Great Britain, RSSB's rail industry standard RIS-7707-INS on switches and crossings (Issue One, December 2023) carries the trap-point requirements, and in Germany the VDV's Schriften group 8, 'Betriebshöfe und Werkstätten', collects the sector's recommendations for depot operation and protection. Third, modern depot personnel protection systems — interlocked derailers, warning devices, controlled access — are procured against project-specific requirements under the operator's safety management system rather than any harmonised product standard. For the adjacent, regulated hardware, start from EN 13232; for the German depot practice, the VDV catalogue.