By 1979, the rail administration was beginning to plan for new suburban train sets. The sets were to be a different design to the last suburban trains, the 'Hitachi' trains.
Testing of equipment for the new trains included self adhesive transfers; pantographs and handbrakes. The couplers were to be changed too. Schaffenburg self centering and electric/air connections were delivered to the Workshops for inspection.
The new contract was awarded to the Comeng, Dandenong factory, despite Martin & King offering an air conditioned 'Hitachi' version. Overhead wire was placed down to the plant and into the siding which was off the Lyndhurst line. A wooden mock up of the car interior was built and inspected by railway staff. Luggage racks were to be provided but during the inspection their use was decided against.
Between 1981 and 1989 the sets were delivered to VicRail, then to the MET administration. To assist with electrical problems, a GEC representative was stationed at Jolimont Workshops for about four years.
The motor cars finally delivered were numbered 301 - 554, 561 - 680, 691 - 698. The sets were made up as three cars in M-_T__-M configuration. The sets were semi-permanently coupled. Cars were fitted with GEC air operated camshaft traction control, rear mount AusBreck pantographs, load compensating brakes, power doors, cast bogies with tread brakes and air conditioning.
On 10/1/1985 the set 477M-1089T-478M-479M-1090T-480M was issued to service with the lettering '45th Super Train' on each car on each side. Whilst the car numbers represented the '45th' set, there had only been about 41 sets issued to that date. The self-adhesive lettering had been removed by January 1991.
Cars 561M, 562M, 563M and 564M were the first cars fitted with LHB ( Link-Hoffman-Busch) disc brake bogies. The set was delivered as 433M, 434M, 435M and 436M respectively. It was renumbered about a week later.
Cars 691M, 692M were 'chopper' control cars. They were released to service as 469M and 470M respectively and renumbered shortly after. Replacement cars re-used these numbers.
The initial sets were delivered in VicRail orange scheme. As all M's were built facing the same way, some M's had to be reversed. As there was no method of turning the M cars at Dandenong, M cars were towed to Melbourne and returned to Dandenong via the loop. Only much later were cars able to be turned at the plant itself.
Cars were changed to green/yellow stripes with curly MTA logo when the Metropolitan Transit Authority was formed about 1984.
With the introduction of 300 series numbers, many Tait _M__ cars had to be re-numbered out of the 301 to 400 block. When car numbers encroached the Tait 400s number block, Tait M cars were renumbered into the 1000s; 470M becoming 1470M &etc.
Cars M 561 and onwards were fitted with Link-Hoffman-Busch disk brake bogies that featured slip-slide equipment.
First car destruction was M 315, destroyed by fire at Hurstbridge 10th April 1983. This car entered service May 1982.