The specification included; a top speed of 160 km/h (100 mph); a terminal-to-terminal travel time of 33 minutes pulling a 2,100-tonne (2,067-long-ton; 2,315-short-ton) train; an axle load limit of 22.5 tonnes (22.1 long tons; 24.8 short tons); an operating temperature range between −10 °C (14 °F) and 45 °C (113 °F);[6] a loading gauge within the UIC 505-1 standard; a minimum curve radius of 100 m (5 chains);[7] be able to start a shuttle train on a 1 in 160 (0.625 %) gradient with one locomotive bogie inoperative (at 0.13 m/s2 (0.43 ft/s2)), and a single locomotive should be able to start the train on the same gradient if the other locomotive failed.

[6][1][8] The main traction electrical system consists of:[note 1] two pantographs (duplicated for redundancy) collecting a 25 kV AC supply which feeds the main transformer, with separate output windings rectified to a DC link (one per bogie) using four quadrant converters.

[4][9] There are two additional output windings on the transformer for the locomotive's auxiliaries and to supply power to the train vehicles.

The traction motors and gearboxes (one per axle) were mounted to the bogie frame and connected to the wheels by a flexibly coupled quill drive.

The locomotive superstructure is supported on coil springs on a central swing bolster, and the centre bogie allows 200 mm (7.87 in) of lateral movement to negotiate small-radius curves.

[13] The driving cab also incorporates train manager's facilities, including safety systems such as CCTV, alarms and communication links.

[13][note 3] The formal opening took place on 6 May 1994 with Queen Elizabeth II and François Mitterrand travelling on a shuttle through the tunnel.

[13] Since 2000, Eurotunnel has been slowly rebuilding the older 9000 and 9100 series locomotives from 5.6 to 7 MW (7,500 to 9,400 hp), replacing the main transformer, traction converters and motors.