The SNCF class BB 15000 is a class of 25 kV 50 Hz electric locomotives built by Alstom and MTE between 1971 and 1978. Initially 65 locomotives strong, the class was widely deployed on the whole French 25 kV network before being replaced by TGV trains when the LGV Est went into service in 2007. History In the mid-1960s, SNCF sought a new type of dual-current electric locomotives. As thyristor technology advanced rapidly, SNCF decided to adopt the new technology for a new series of locomotives, later known as the Nez Cassés (Broken Noses, due to their cab styling by Paul Arzens) or BB 4400 kW. Given that the need for pure AC-locomotives was greatest, SNCF placed an initial order of five locomotives in 1968. In 1969 a second order of 10 locomotives followed, in 1970 a third order was made for another 10 locomotives. The remaining 40 locomotives were ordered in 1973. The first five locomotives were delivered in 1971 in the overall-green "Maurienne" livery. The rest followed between 1973 and 1978, painted in the striking TEE-Arzens livery. Initially meant to support BB16000 locomotives on eastern and northeastern lines, which could not keep up with the timetables anymore after top speed on some sections was raised to , the BB15000 series would become the most important locomotives on the northern and northeast network. Career 1970s-2007 After being tested on the Paris–Épernay main line in 1971, they entered revenue service from 1972. They ran mostly on the northeastern network where they hauled nearly all the principle passenger trains, including the national TEE trains Kléber and Stanislas. Some services extended to the northwest, with workings to Lille, Calais and the Belgian border at Quévy. Services remained stable throughout the 1970s and 1980s, but the opening of the Ligne-a-Grande-Vitesse Nord in 1993 started a cascade of assignments in which the BB 15000's lost services to either dual-voltage BB 26000 locomotives or to TGV trains. Yet BB 15000 locomotives remained strong in the northeast and hauled Corail Téoz services between Paris and Strasbourg from 2003 until mid-2005, when half of the loco-hauled services were converted to TGV trainsets, albeit still running on the classic line. In mid-2006 the remainder were also converted into TGV services, leaving only some TER trains for the Lorraine and Alsace regions, and the EuroCity trains between Basel and Brussels (loco change at Luxemburg) or Paris and Frankfurt (loco