British Rail Class AM1

Class AM1 was allocated to the prototype AC electric multiple units, converted from fourth-rail DC electric stock in 1952 and used on the Lancaster/Morecambe/Heysham route. This route had been electrified by the Midland Railway at 6.6 kV, 25 Hz AC, but the frequency was changed to 50 Hz in 1953 to test the prototype AM1 stock.

The line was closed to passengers and the stock withdrawn in early 1966. Unlike classes AM2-AM11, which became TOPS Classes 302-311, class AM1 was withdrawn before it could take its place in the system as class 301. However, it was the success of these tests that contributed to the decision to choose 25 kV AC overhead electrification as standard in Great Britain outside the Southern Region.

Previous use

The carriages converted to form the prototype units were drawn from former LNWR electric units built in 1914 by the Metropolitan Carriage, Wagon & Finance Company for use on the West London line fourth-rail DC electrification. They had been stored early in World War II after the West London route on which they worked was closed to passengers due to bomb damage.

Formations

Unit numbers were not allocated, but sets were referred to by the last two digits of the DMBSO number. The numbers of individual carriages were:

ee also

* MR electric units
* Morecambe Branch Line

ources

* 100 Years of Electric Traction by Colin J Marsden, published by Oxford Publishing Company in 1985, ISBN 0 86093 325 3