it into DC, which is then fed into the traction motors. Brake equipment consists of pneumatic, electro-pneumatic, regenerative and dynamic brakes. The monomotor bogies were derived from the Y217 bogies of BB67400 locomotives and have primary (coil springs) and secondary ("sandwich" blocs) suspension. The reliability of the locomotives is outstanding, as some locomotives have already passed the 10,000,000 km mark and have less than 2 defects per million kilometres, a number unrivaled by other similar European locomotives. Liveries BB15000 locomotives have carried at least six different liveries: The green "Maurienne" livery (so called because CC6500 locomotives also wore this livery and operated in the French Maurienne region) was worn by locomotives BB15001 - BB15005 between their delivery and 1982, when they were repainted into the TEE-Arzens livery. The TEE-Arzens livery was worn by locomotives from number BB15006 onwards by delivery; the first five green locomotives were also repainted in this livery in 1982. There were two variants of this livery: the original livery which consisted of silver, red and orange, and the modified one where the silver was replaced with opaque gray. Nowadays a number of locomotives still wear the original livery, the others having another one listed below. The "béton" (lit. concrete) livery, which was the standard livery of BB7200 and BB22200 locomotives, was tested on locomotives BB15034 and BB15040 in 1986-87 but was considered a failure as the locomotives got dirty too fast. The "Multiservices" livery (former known as Corail+, as on the coaches) was introduced in 1995 on BB15016 and consisted of two shades of gray, silver and red. Nearly half of the class was painted in this livery by 2002, when the new "en voyage..." livery was introduced on the series. The "en voyage..." livery was the latest livery of the class. Introduced on BB15063 in 2002. It consists of silver, purple on cab side 1 and cyan on cab side 2, and the "en voyage..." sticker with stylish motifs. The rights to use this design have expired and all locos still wearing it will be repainted in something else upon their next overhaul. A number of BB 15000 locos have been repainted in TER liveries of the regions where they run. The experimental nature of the class BB15000 locomotives were popular locomotives for conducting various experiments. A small overview: In 1972, BB15001 was used for testing a potential speed raise to on the Paris-Strasbourg main