way for the second order of X'Trapolis trains, which would also start from 1. The remaining M cars were renumbered from 273M up to 300M, however the new numbering does not reflect the age of each car. The numbering reflects which T car is in each set, the lowest numbered T car receives the lowest numbered M cars, in order of which M car was already the lowest (for example, 2007T was the highest-numbered T car, so 23M was renumbered 299M as it was lower than 233M, which was renumbered 300M). Service Intended to replace the first generation of electric trains, the Swing Door and Tait, the stainless steel Hitachi was the first Melbourne suburban train to feature heated carriages and power-closing doors operated by the guard, and opened by hand. The M and D carriages were built by Martin & King, and the T carriages by Victorian Railways at their Newport Workshops. The first to operate in revenue service was the four-carriage set 1M-901T-902T-2M, on 24 December 1972 on the St Kilda line (since converted to light rail). Trains originally wore a plain stainless silver livery, receiving green and gold side stripes with the introduction of the Metropolitan Transit Authority. Side logos were altered with their re-branding as The Met, and were again altered with the privatisation of The Met's metropolitan rail services as Hillside Trains (later Connex), and Bayside Trains (later M>Train), with the latter also applying branding to the front. When the carriages were refurbished under Connex, the green and gold livery was removed, restoring the carriages to their original 'silver' colour, with the addition of Connex blue and gold striping on the front face of the leading cars, and two blue and gold side panels near the driver's cab. The seats in the passenger area also received new fabric, similar to that of an Alstom refurbished Comeng. With the takeover by Metro, the Connex logos were covered up with Metro stickers. Beginning in 1992, the Hitachi fleet received internal, external and cab upgrades at the PTC's Ballarat North and Bendigo Workshops. The refurbishment included the replacement of the steel flooring in each car where it has reached the end of its service life, replacing existing rubber or carpet flooring with vinyl, replacing interior panels above the seats with a new anti-vandal material, replacing the woodgrain upper panels and bone-coloured roof with off-white panels, new seat pads