Graviner is a British engineering company that makes oxygen (life support) and fire extinguishing systems for civil and military aircraft.
The system deployed the compound carbon tetrachloride, the forerunner to the modern gaseous extinguishing agents collectively referred to as Halon.
All Diesel Multiple Units (referred to as 'Railcars' at the time) built in the 1950s and 1960s, had the system installed around the underfloor mounted engines and transmissions.
The original systems remained in use right up until the last units were withdrawn from the, by now Privatised National Rail system in the early 2000s, and remains installed on the many preserved DMUs on heritage railways, although most have had the original extinguishing medium (CTC) replaced with non-toxic, modern Halon based medium.
It also made fire detection systems for marine craft; it makes a well-known oil mist detector.