prior to the war in 938 MNR had been researching Alternating Current traction electrification for the Lakeshore Mainline and in 946 had to decided to begin research on grid frequency AC electrification and in 947 had decided on 18.5kV 50 hertz AC with a 2-6-2 Jackshaft boxcab design being selected 25 were produced they were in service on commuter trains 960 as by this point all of the M7 multiple units had been delivered and were transfered over to local freight and later the electrified branchlines they remained in this role all the way up until 996 as by this point there was a large enough surplus of diesel locomotives to operate local freight and diesel locomotives could operate anywhere on the system not just the AC electrified lines the ES-5 used Asynchronous body mounted Traction motors with an adjustible number of motor poles however later MNR AC locomotives would use DC motors with rectifiers based on the Swedish State Railways Jackshaft boxcab's and the Canadian National Railways Z-4a
