The InterCity 225 is an electric high speed train in the United Kingdom, comprising a Class 91 electric locomotive, nine Mark 4 coaches and a Driving Van Trailer (DVT). The Class 91 locomotives were built by British Rail Engineering Limited's Crewe Works as a spin-off from the Advanced Passenger Train project, which was abandoned during the 1980s, whilst the coaches and DVT were constructed by Metro-Cammell in Birmingham and Breda (under sub-contract) in Italy, again borrowing heavily from the Advanced Passenger Train. The trains were designed to operate at up to in regular service, but are limited to principally due to a lack of cab signalling and the limitations of the current overhead line equipment. They were introduced into service between 1989 and 1991 for intercity services on the East Coast Main Line (ECML) from to , and Edinburgh. History Background The origin of the InterCity 225 is closely associated with the East Coast Main Line (ECML) that it has been primarily operated upon. During the 1950s, British Rail had considered electrification of the ECML to be of equal importance to the West Coast Main Line (WCML), but various political factors led to the envisioned electrification programme being delayed for decades; as an alternative, high-speed diesel traction, including the Deltic and InterCity 125, was introduced upon the route during the 1960s and 1970s. During the 1970s, a working group of British Rail and Department for Transport officials determined that, out of all options for further electrification, the ECML represented the best value by far. Its in-house forecasts determined that increases in revenue and considerable reductions in energy and maintenance costs would occur by electrifying the line. Accordingly, between 1976 and 1991, the ECML was electrified with 25 kV AC overhead lines. The electrification was installed in two phases: The first phase between London (King's Cross) and (including the Hertford Loop Line) was carried out between 1976 and 1978 as the Great Northern Suburban Electrification Project, using Mk.3A equipment, covering 30 miles in total. In 1984, the second phase commenced to electrify the Northern section to Edinburgh and Leeds. During the late 1980s, the programme was claimed to be the longest construction site in the world, spanning more than . During 1989, the InterCity 225 was officially introduced to revenue service. That same year, the ECML had been energised through to York; two years later, electrification had reached Edinburgh, allowing electric