Design

Experience with the previous Hitachi sets had shown their electrical equipment was reliable, but the combination of a stainless steel car-body combined with a carbon steel framework had caused serious corrosion issues,^[7]: 123 so an all-stainless steel design was preferred. This placed Commonwealth Engineering, and their Dandenong rolling stock factory, in a prime position to tender, as they held the Australian license for the Budd Company's stainless steel rolling stock construction techniques.^{[citation needed]} Comeng submitted their tender on 10 April 1978, and the contract was awarded in April 1979.^{[7]: 123–124}

The original carriage design used a stainless steel structure with glass-reinforced plastic (GRP) trimmings, but manufacturing constraints resulted in a whole front panel for each motor car being made with the GRP material, hiding the stainless steel structure.^[7]: 125

A full-size, half-length mock-up of a Comeng motor car was constructed at the Dandenong factory to help VicRail staff visualise the final concept. Photos of the mock-up show a dark blue outline around the front of the carriage, stretching down to a pilot just above the rails, and fittings on the exposed stainless steel motor car front including the final marker lights, but also a taildisc on the centre pillar and a destination disc below the driver's window. This design originally included luggage racks above the windows, but these were not provided in the final model. The window surrounds were also GRP, and the internal ceilings were formed with pressed aluminium sheets with recesses for light fittings, derived from a previous Comeng contract for the Hong Kong MTA.^[7]: 125

The underframes followed the normal Budd/Comeng technique of 350-grade carbon steel end units, combined with stainless steel side sills and transoms, but with Corten-steel corrugated floor sheets spot-welded to the underframe structure along the whole length of each carriage. This was necessary to achieve VicRail's stated requirement for end-loading strength, which was specified at three times that of the existing rolling stock. The first body shell was railed from Dandenong to Comeng's Granville plant for testing, and passed all tests.^{[7]: 128–129}

Electrical systems were all centralised to a common control panel, rather than being located with each piece of equipment spread around the carriage underframes.^[7]: 130

From a passenger comfort perspective, the carriage design was the extremely large window panes.^[7]: 129 Previously, all suburban air conditioned rolling stock in Australia had been designed as carriages first, and then handed to air conditioning manufacturers to design and provide the necessary equipment to achieve specified climate control requirements. The Comeng design flipped that script, instead bringing the air conditioning manufacturers onboard much earlier and this allowed a design with a lower profile, avoiding significant projection above the carriage roofs. The air conditioning units were designed to be lowered onto the carbody, automatically connecting to the air ducts and with only a single electrical connection, isolated from the drainage system. This design principle allowed the modules to be exchanged in as little as ten minutes.^[7]: 130

Cast-steel bogies were provided by Bradford-Kendall, which led to some internal political issues between them, Comeng, and Australian National Industries.^[7]: 130

An unusual but useful feature of the trains was a switch provided in the guard's compartment, which would enable single car operation. When in use, this system would switch off the lights and lock the doors of the leading and middle carriage, leaving only the trailing carriage for passenger use under observation of the guard.^{[8][better source needed]} This feature was rendered obsolete when two-person crews were abolished on the Melbourne suburban system, and abandoned when the early 2000s refurbishments of the Comeng fleet introduced inter-carriage walkways.

Construction and delivery

Stainless steel sheets were seam-welded together, then placed in jigs and rolled to shape to form the carriage bodies, while underframes were inverted for equipment and piping attachment then flipped and mated to the car shells before final fit-out.^{[7]: 126–127}

A limited 1,500V power supply was provided at the Comeng factory to allow testing of the trains' internal systems before leaving the compound, then as each set of carriages was completed they were tested on a short siding parallel to what is now the Cranbourne railway line, running south-east from the Comeng factory.^[7]: 131

Entry to service

The first Comeng set, 301M-1001T-302M, entered service on 28 September 1981. By the middle of 1984, 76 sets had been delivered, and some of the older trains, including the last of the Tait rolling stock, had begun to be phased out. Following the operational problems and subsequent failed refurbishment of the Harris fleet, the initial order was increased from 100 to 190 3-car sets, with the aim of completely replacing both the Tait and Harris sets by 1988.^[9]

The first sets experienced issues with the GEC traction equipment^[7]: 132 that had originally been suggested by VicRail,^[7]: 124 as it had proven successful in Ireland and Hong Kong but was not suited to Melbourne's climate, including higher ambient temperatures and dust issues, particularly affecting the camshafts. These issues were magnified by late component delivery from GEC's factory in England, and discussions between the Comeng team and GEC's chairman led to some sets of equipment being airfreighted over to Dandenong to avoid production line delays.^[7]: 132

Electric train drivers were rostered and trained en-masse for use of the new trains, which led to some drivers being taught how to operate the new equipment but then not using that knowledge for months; to overcome the issue Comeng provided electricians in the driving cabins to remind the train drivers how to operate the new equipment.^[7]: 133

Set 381M-1041T-382M was the first delivered in the Metropolitan Transit green and yellow scheme, though the sets including 27T and 28T had been repainted (with those cars renumbered 1027T and 1028T respectively) before then.^[10] Notably, when the 41st set was delivered the front panels of the motor carriages were grey or silver-framed rather than the earlier orange or later yellow.^[11]

Due to the ongoing issues with GEC's traction equipment, set 469M-1085T-470M was fitted with AEG camshaft control equipment instead. It performed admirably but due to no further decisions being made, it remained an orphan set.^[7]: 133

In parallel with the development of the Comeng fleet, a separate contract had been won by Comeng in early 1981 to refurbish the Harris fleet. This project ended up being more costly and less successful than originally anticipated, and Comeng and the Railways eventually agreed to terminate that project with the fourth four-carriage set and use those resources to extend the new train contract in lieu.^{[7]: 205–208} The contract extension signed in late 1982 for the Comeng trains saw the total number increase from 100 to 190 three-car trains.^[7]: 208 The additional trains provided an opportunity for Comeng to introduce a new fabricated bolsterless type of bogie, manufactured by Salzgitter in Germany to the design of Linke-Hoffman Busch (LHB), and fitted with Chopper equipment, which overcame the weight issues of the cast steel Bradford-Kendall bogies and the electrical issues with the GEC traction equipment, while also allowing recycling of the Mitsubishi traction gear originally intended for the Refurbished Harris train project.^[7]: 208 The new bogies also use Knorr disc brakes rather than traditional tread brakes.^[7]: 209 The first batch of bogies were provided from Germany, with the balance of manufacturing work split between Comeng and the Railways' Newport Workshops. The disc brake equipment was tested on set 433M-1067T-434M-435M-1068T-436M in the workshops, before that set was converted to the normal configuration on release to VicRail.^[12]: 275

As of 15 July 1985, all sets in service except 321M-11T-322M, 317M-9T-318M, and 339M-20T-340M, were converted from the orange livery to the green livery.^[13]: 278

The 45th set delivered had custom decals applied to the sides celebrating the halfway point through the order. On the side (above each door) was the quote "45th Super Train from The Met", and the sides also displayed the number 45 in large Numerals below the windows. This was found on two sets, 477M-1089T-478M and 479M-1090T-480M. These had been removed by 1 February 1991. 477M-1089T-478M still remains in service, but 479M-1090T-480M was stored at North Shore before being scrapped in early 2022.^[14]

The final Comeng set to enter service was 697M-1199T-698M, being delivered on 2 June 1989^[7]: 209 and entering service on 24 July 1989.^{[citation needed]}

Refurbishment

2000–2003

Between 2000 and 2003, the two train operators at the time, Connex and M>Train, had Alstom and EDi Rail respectively refurbish the trains.^[15][16]

The Alstom and EDi Rail sets have a number of differences, including:

• Interior arrangement – The interior LED displays on the M>Train trains were in the middle, as opposed to being at both ends of the carriage on Connex sets.
• Upholstery – Seats in M>Train trains were given a blue texture, while Connex opted for rainbow-textured seats, with scattered letters spelling out "Connex".
• Seating arrangement – Both operators designed their carriages different seating layouts.
• Exterior front panels – Information on the train's terminus is displayed on top of the window on M>Train fleets, while Connex trains have them displaying on the right window (in pre-refurbishment style).
• Cab layout – The EDI Rail refurbished trains retained a second full-size seat on the right-hand side of the cab, originally used for the guard, whereas the Alstom sets only have a small seat, the same size as the passenger ones.
• Cab fittings – The EDi Rail trains also have a windscreen-wiper on both sides, the Alstom sets only having one on the driver's side.
• Light fittings – The Alstom refurbished trains have grated light coverings, while the EDi type retained the original flat coverings.
• And Early on the electric systems were incompatible between the 2 types, thus they could never run coupled. But then in the later years they were modified to be able to run together.

Both sets had CCTV and emergency assistance panels introduced and installed as part of the refurbishment program.^[17]

After Connex assumed responsibility for all of Melbourne's suburban train network in 2004, the EDI refurbished trains (from M>Train) had the M>Train exterior logos removed with a new Connex logo in its place alongside a repainted front panel. The trains also later received Connex blue and yellow side stripes, new seat fabric with the Connex branding.

Concorde program

2006–2007

From December 2006 both fleets were allowed to run system wide. The electronics of both Comeng types were altered to make them electronically compatible with each other, with both the PID voices and display formatting altered. Both types of Comeng can run system wide and can run in multiple unit with trains of the same or different type.

Interior rearrangements

2009

From the beginning of March 2009, Connex ran a test set of carriages with new seating arrangement on city lines.^[18] The new arrangements removed 44 seats, making room for more standing on the train. The changes were made to accommodate the increased patronage on the Melbourne rail network.^[19]

Door upgrades

2014–2015

Comeng trains require passengers to manually open saloon doors to enter and exit the trains. Pneumatic air pressure keeps the doors closed whilst the trains are in motion, and is released by the driver when the carriages stop at station platforms. Prior to 2014, the doors were fitted with large "door knob" style handles. These made it relatively easy for unruly passengers to force the doors open, including while the train was in motion. All carriages were retrofitted with a new flat slim handle designed to make doors more difficult to force open. This followed an incident at Watergardens railway station where teenagers forced open a door on a moving train and one jumped out, injuring himself. Alan Osbourne, then director of Transport Safety Victoria (TSV), informed Metro that the Comeng trains would be taken out of service if their doors were not made impossible to force open by 2017.^[20]

Life extension

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2017–2021

Alstom Comeng

EDI Comeng

Life extension refurbishments were carried out between 2017 and 2021

From 2017 to 2021, the entirety of the existing Comeng fleet undertook a $75 million life extension refurbishment program with a number of upgrades taking place in order to allow the fleet to operate reliably and safely for at least another decade prior to their retirement.^[21][22] These upgrades were carried out in stages (1, 2 & 3), focusing on external, internal, mechanical and safety system upgrades.

Stage 1 of the life extension refurbishment works revolved only on exterior modifications, with much of the mechanical and safety systems remaining the same and their interiors largely unaltered from their 2014/2015 modifications. 25% of the existing Comeng fleet undertook only the stage 1 life extension refurbishment. The stage 1 upgrades include:

• LED marker lights
• New vinyl stickering with PTV branding identity livery on the exterior fibreglass front panels.
• Removal of external handles and step ladders at the leading end of all motor cars to reduce instances of train surfing.

Original (pre 2000's)

EDI Comeng with Connex interior after transfer from M>Train

EDI Comeng – Stage 2 upgrades

Stage 1 upgrades did not affect the interior of the trains as they were only external changes.

Stage 2 of the life extension refurbishment works concentrated on both interior and mechanical upgrades, with 75% of the existing Comeng fleet undertaking the stage 2 refurbishment. In addition to the stage 1 upgrades, the stage 2 upgrades include:

• Updated upholstery – Seats in Connex rainbow-textured pattern were updated to Public Transport Victoria's corporate identity in either blue or orange (priority seating) geometric design.
• Additional and upgraded grab handles and poles.
• Concertina style enclosed gangways between carriages.
• Improved saloon lighting and additional handholds.
• Door upgrades.
• Improvements to the driver's panel.

Stage 3 of the life extension refurbishment works focused on communications and additional mechanical upgrades, with 31% of the Comeng fleet, namely the disc brake units, having been further enhanced with these upgrades. These sets will more than likely be the last Comeng sets to remain in service when they will be eventually retired. In addition to the stage 2 upgrades, the stage 3 upgrades include:^[23]

• New external LED destination signs.
• New dynamic Passenger Information Screens which displays real time data.^[23]
• Improved safety enhancements, including an upgrade to high definition CCTV cameras with better clarity and a wider field of view, and new emergency help points.^[23]
• Improvements to hearing aid links with a new and upgraded speaker and onboard announcement system.^[23]
• Improvements to the overall air compression system powering the brakes, doors, pantographs and traction systems.

The life extension refurbishment program was completed by the end of 2021 with 75% of the Comeng units having undergone the stages 2/3 upgrades. As of June 2023, all stage 1 sets, along with some stage 2 sets have been scrapped, having since been replaced by the High Capacity Metro Trains.

Horn upgrades

2023–2024

In May 2023, 12 Comeng sets were trialled with a new Zöllner Makrofon 370 single tone horn, sounding similar to an X'Trapolis 100 horn, to replace the Roy Victor Butler (RVB) three chime horn. After it was deemed successful, from November 2023, the rest of the Comeng fleet started to receive the new horns, and was completed in late March 2024.^[24]