in 1005 MNR-Munita decided to purchase new electric multiple units to replace the old M7 multiple units which were almost 50 years old and need of replacement, the new M17 would be bith the first bilevel and dual-voltage trains to be used on the Portbell Suburban railways as they were capable of switching between 3kV DC and 18.6kV AC power seemlessly the M17s were delivered starting in october of 1009 until april of 1014 like the M12 and M7 the M17 used stainless steel construction but used VFD AC traction control instead of restitive or chopper control, and they instead had three-phase AC induction motors they were also faster with a top speed of 110 mph instead of the 82 mph of the M7 and M12
