In 1955, the British Transport Commission (BTC) launched a Modernisation Plan
for Britain's railways. Key to the plan was the eradication of steam and the
rapid electrification of key routes throughout the British Isles. Thousands of
miles of main line, suburban routes and even country byways were earmarked for
electrification using overhead wires. At the time the standard overhead system
was 1500V DC, pioneered by the NER and developed by the LNER. It was used in BR
days between Manchester and Sheffield, on the Woodhead route, from Manchester to
Altrincham on the MSJ&A suburban route, and on the London Liverpool Street
to Shenfield line.
The West Coast Main Line (WCML) from London to Birmingham, Liverpool and
Manchester was chosen to be the first long distance route electrified, however,
in 1956 the BTC decided to adopt a new overhead wire system of 25,000 V AC. This
system, which promised construction, maintenance and efficiency savings over the
1500V DC system, was chosen following extensive trials in France, despite the
existence of several DC equipped routes in the UK. A comparitive study at the
time suggested that the costs of re-equipping the Shenfield route would be more
than outweighed by the savings offered nationally by adopting the AC system.
There may also have been political reasons for adopting AC, particularly to
encourage British Locomotive manufacturers to gain experience with the new
technology, thus generating export orders. In any event, these manufacturers
were given orders for 100 'prototype' locomotives, in five different designs,
for use on the first section of the electrified WCML.
The first stretch of the WCML equipped with the 25kV supply was the Styal
line, a loop off the Manchester branch of the WCML, avoiding Stockport. This was
energised in 1958, long before any of the production locomotives were ready for
use. For driver training purposes, a Western Region Gas Turbine test locomotive
(18100) was converted into an electric locomotive (E1000 - later E2001) and put
to use on test trains on this line.
A year later, in November 1959, the first AL1 (Class 81), E3001, was
delivered, to be followed over the next four years by a further 99 locomotives
from Classes AL1, AL2, AL3, AL4 and AL5.
Electrification through from Manchester to Crewe was completed in time for a
public launch on 12 September 1960, with the route from Crewe to Liverpool
following in 1961. Over the next few years the wires gradually extended south,
first to Rugby and eventually, in 1965 to Birmingham and London Euston, when the
second generation of AC locomotives began to appear.
Text from the AC
LOCOMOTIVE GROUP website