was closely based on that of the Class 86. The only major visual difference was that the 87 had two front cab windows, instead of the three of the 86, and also lacked a headcode indicator box; by 1973, visual recognition of train reporting numbers by signallers was no longer deemed to be necessary. The Class 87s were higher performance locomotives than the preceding Class 86, with increased power and speed: power output was increased from to deal with the more demanding gradients on the northern half of the WCML, such as Shap and Beattock Summit. The top speed was raised from to , which is the fastest speed allowed on the West Coast Main Line for trains without a tilting mechanism. The Class 87s were also fitted with multiple working equipment, which enabled locomotives to work with other members of the class, and some Class 86s, while controlled by one driver. During the 1980s, the original multiple working system was replaced with a newer system that was based on time-division multiplexing (TDM). The new apparatus enabled the Class 87 to work with various other classes of locomotives, including Class 86s, Class 90s and Class 91s. Perhaps even more importantly, the newer multiple working equipment had also enabled the type to work with the newly-introduced Driving Van Trailers (DVTs). 87101 Whilst the first 35 locomotives (numbered from 87001 to 87035, known as Class 87/0) were identical, the 36th and last member of the class, which was going to carry the number 87036 before entering traffic but was allocated 87101 instead, had major equipment differences from the rest of the class: While the 87/0s were fitted with a traditional tap changer transformer and rectifiers, 87101 had a new thyristor power control system, and better anti-slip protection. and spent over a year on test before entering service in 1976. It was reported that the locomotive's hauling ability was around 20% better than the 87/0's, a feature which made it particularly suitable for freight work. The locomotive, named Stephenson after transfer of the name from 87001, worked the same services as the standard locomotives for many years, until British Rail was sectorised in the 1980s. The locomotive was then transferred to Railfreight in 1989, to be used exclusively for freight work, and was limited to . As a freight locomotive, it was transferred to EWS and, after suffering a major failure, the locomotive