InterCity 125 - Numbering and Formation

Numbering and Formation

When Crewe Works built them, the InterCity 125 units were considered to be diesel multiple units, and were allocated British Rail Class 253 and Class 254 for Western and Eastern Region services respectively.

British Rail considered the HST, a fixed formation train with a locomotive at each end, as a multiple unit on introduction, and numbered them as such: 253 xxx (Western Region) and 254 xxx (Eastern and Scottish Regions). However, because two power cars carried the same 'set number', problems arose when, for servicing reasons, different units were used on a train, which would then display a different number at each end. For this reason, British Rail abolished the initial numbering system and all individual power cars became identified as such, using the format 43 xxx - this number was previously carried in small digits in the bodysides, prefixed by a 'W' for Western, 'E' for Eastern or 'Sc' for Scottish to identify the region, thus the power cars were reclassified as Class 43 diesel locomotives.

The vehicle types used to form High Speed Trains are listed below:

The 197 power cars produced are numbered 43002-43198. 43001 was applied to the second of the two prototype power cars, while the first of the pair (now preserved at York) became 43000 - unusual because BR TOPS classification numbered its locomotives from 001 upwards (this was because it was not, at the time, classified as a locomotive).

In 2002, Class 255 was allocated for the reformation of some HST power cars and trailers into semi-fixed formation trains, to be known as Virgin Challenger units, for use by Virgin Trains. These formations would have had power cars sandwiching one Trailer First, a Trailer Buffet, two Trailer Seconds and a Trailer Guard Second. These plans came to naught as the Strategic Rail Authority planned to transfer most of the stock to Midland Mainline for its 'Rio' services between London and Manchester.