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 services to begin on 8 July 1991, eight weeks later than scheduled. The ECML electrification programme was completed at a cost of £344.4million (at 1983 prices), a minor overrun against its authorised expenditure of £331.9million. 40 per cent of the total cost was on new traction and rolling stock and 60 per cent for the electrification of the line. Options and selection The electrification of the ECML necessitated the procurement of new high speed electric traction. The options and requirements for this trainset were hotly deliberated for a number of years. On 7 June 1978, the electric-powered prototype Advanced Passenger Train (APT) was unveiled; it was at one point intended for the APT to be the next major intercity express train. However, due to various factors including technical issues, the APT programme was curtailed during the summer of 1983. Shortly thereafter, two alternative options were explored, an electrified version of the InterCity 125 (known as the HST-E), and the mixed-traffic locomotive; these were both intended to a peak service speed of 125mph. Some officials within British Rail pushed for more demanding requirements for the future Intercity trainset; reportedly, BR's Director of Mechanical and Electrical Engineering (M&EE) was a strong proponent for increasing the top speed to 140 mph. To facilitate this, tilting train technologies developed for the APT were explored. While BR's board had approved the ordering of a single Class 89 as a prototype, the Strategy Committee queried why the type had been favoured over a proposed 80-tonne Bo-Bo locomotive. While the Class 89 was thought to be a low-risk option for multi-purpose traction, it offered little advantage over the existing in terms of speed. At the time, the 1950s era and electric locomotives were nearing the end of their viable service lives and were quite unreliable, but their withdrawal had effectively been ruled out by a national shortage of newer electric traction, in part caused by the APT's cancellation. A key advantage of the InterCity 225 concept over a Class 89-hauled consist was the lower weight of the former, resulting in less slippage and greater acceleration over the latter. Appraisals also determined that the Class 89 was comparatively inferior