allows of lateral movement to negotiate small-radius curves. Yaw dampers are also fitted. The locomotive superstructure is a stressed-skin monocoque design. The driver's cab and exterior design of the locomotives was undertaken by DCA Design, Warwick, UK. Side windows in the locomotive cab are omitted to prevent 'segment flicker' caused by fast running in the tunnel, a potential distraction and cause of driver drowsiness. The driving position was air conditioned and pressurised, and incorporated in-cab TVM 430 signalling. The driving cab also incorporates train manager's facilities, including safety systems such as CCTV, alarms and communication links. There is a second driving position for shunting at the rear of the locomotive. Testing and operations The initial order for 40 units was reduced to 38, numbered 9001 to 9038. The first locomotive was completed in 1992, and two units (9003 and 9004) were tested at the Velim test track in the Czech Republic. Locomotive 9004 started its required 50,000-kilometre endurance test at Velim on 17 August 1993 and finished it on 23 September 1993. The locomotives are maintained at the Eurotunnel depot located just beside Eurotunnel Calais Terminal at Coquelles near Calais, France. The formal opening took place on 6 May 1994 with Queen Elizabeth II and François Mitterrand travelling on a shuttle through the tunnel. The 1996 Channel Tunnel fire damaged locomotive 9030 beyond repair. Later subclasses 9100 subseries In 1997, Eurotunnel ordered five more locomotives and in 1998 the order was increased to a total of 14. This second batch of locomotives also had small improvements compared to the originals, including IGBT-based traction inverters instead of GTO-based and one inverter per motor instead of one per bogie. This second batch of locomotives is numbered in the 9100 series (9101 to 9113) except for one locomotive, 9040 which was purchased as a replacement for 9030, the locomotive destroyed in the 1996 fire. 9700 subseries In 2000, Eurotunnel ordered seven locomotives with an increased power of . This third batch of locomotives is numbered in the 9700 series (9701 to 9707) and deliveries ended in 2003. These more powerful locomotives are used to pull the freight truck shuttles, which were able to be increased in length. 9800 subseries Since 2000, Eurotunnel has been slowly rebuilding the older 9000 and 9100 series locomotives from , replacing main transformer, traction converters and motors. These rebuilt locomotives are numbered in the 9800 series. By 2018