British Rail Class 87 - History

History

A requirement for more electric locomotives came about after the electrification of the WCML was extended from Weaver Junction north of Crewe to Preston, Carlisle and Glasgow. Initially, three Class 86 locomotives were used as test-beds to trial equipment (mainly electrical equipment and suspension) that would be used in the new locomotives; effectively, these locomotives were Class 87s in everything but appearance.

The external design of the Class 87 was clearly derived from that of the Class 86; the only major detail differences were two front cab windows on the 87 instead of the three of the 86, and also the lack of headcode indicator boxes; by 1973, visual recognition of train reporting numbers by signallers was no longer necessary. The 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. Power output was also increased to 5000 hp in order to deal with the more demanding gradients on the northern half of the WCML such as Shap Fell and Beattock Summit.

In the 1980s, the multiple working system was replaced with a new system based on time-division multiplexing (TDM) allowing 87s to work with other classes of locomotive (including most 86s, 90s and 91s) and most importantly, Driving Van Trailers (DVTs).