the M12 multiple unit was built as part of the Portbell Suburban Railway Reorganization program where the various suburban railways (both Electrified and not) and their respective terminals were linked, upgraded, and seperated from freight and road traffic via a number of tunnels, flyovers, junctions, and trenches which allowed through-running of the various lines and allowed AC powered trains to access Portbell Lakston Station the M12 was very similar to the M7 they both used mostly stainless steel construction, with restitive traction control
