British Railways Class 505 were 1,500 V DC electric multiple units (EMUs) introduced in 1931 by the Manchester, South Junction and Altrincham Railway (MSJAR). Although assigned to TOPS Class 505 by British Railways, these units were withdrawn before the TOPS numbering system came into common use for multiple units, and the Class 505 designation is very rarely used. Following the 1923 Grouping, the MSJAR company was owned jointly by the LMS and LNER. It operated a route between Manchester London Road (now Manchester Piccadilly) and Altrincham in Cheshire. The MSJAR was electrified in the early 1930s on the 1,500 V DC overhead system. Overview Twenty-two 3-car EMUs and two spare power cars were built for the new electric service, which started on 11 May 1931. It was common with the earlier generation electric trains for the power cars to require much more engineering workshop time than the trailers, and several systems had additional power cars built. These trains were based at Bowdon depot and ran exclusively between Manchester and Altrincham for forty years. In 1939, eight additional trailers were added, both new build and secondhand conversions, inserted into eight of the 3-car sets, and these allowed 7-car trains to be run on many peak hour services. The Altrincham electrics had substantial power installed and were well able to handle the extra car. As with other Manchester area suburban electric services, demand reduced notably from the 1950s onwards, and the 7-car trains were eliminated. Route shortened The 1931 service ran from Altrincham, through Manchester Oxford Road, to Manchester London Road (nowadays Manchester Piccadilly). In 1961 it was decided to extend the 25 kV electrification project from Crewe to Manchester Piccadilly through to Oxford Road station, and thus the Altrincham electric trains had to be cut back to that point, where new terminal platforms for them were provided in a rebuilt station. The long term intention was to link the two routes as a through service, but this did not happen for another 10 years. Withdrawal and preservation In April 1971, all the Class 505 Altrincham Electric units were withdrawn when the line was converted from 1,500 V DC to . Two centre trailer cars, M29666 and M29670 (MSJAR 117 and 121), were purchased by the Altrincham Electric Railway Preservation Society and moved to the Yorkshire Dales Railway (now Embsay and Bolton Abbey Steam Railway). In 1983, they were moved to the