The Siemens Nexas (known colloquially as the Siemens Train) comprises 72 triple car electrical multiple unit trains built by Siemens Transportation Systems for the suburban railway network of Melbourne, Australia from 2002-2005. The design of the trains was based on the Siemens Modular Metro (Mo.Mo) concept built in Austria. Introduced to service in 2003, the trains are the newest in the city's suburban fleet, however the Victorian State Government has recently ordered more of the previously delivered Alstom X'trapolis_100 trains.
Unlike the Connex Melbourne/Hillside franchise and its X'Trapolis trains, the Siemens trains were not originally proposed by National Express in the privatization agreement. The original contract specified trains built by Clyde Engineering (now EDI Rail) using Adtranz (now Bombardier Transportation) traction equipment.
Melbourne's original order was for 62 3-car sets,) The metropolitan network is now run wholly by Connex Melbourne, with ownership of the Siemens trains transferred in April 2004. but an additional ten trains were ordered by Connex Melbourne in August 2005, with the last of these trains delivered in February 2006.
The shuttle service between Williamstown station and Newport station was replaced with 3-carriage (M-T-M) Siemens trains on October 11, 2005. From around the same time, the Siemens trains could regularly be seen off peak and peak on the Caulfield Group (that is the Pakenham, Cranbourne, Frankston, and Sandringham lines), running as 3-car sets in off peak periods and 6-car sets in peak periods.
Like the Connex X'Trapolis trains running exclusively on lines owned by Connex prior to gaining ownership of M>Train's lines, the Siemens trains never run revenue services on lines owned by Connex prior to the merger.
On the 13 January 2007, Connex stopped running the Siemens trains as 3-car sets until the braking issue was resolved, with the result that all services (including evenings and weekends) on the Caulfield Group were operated by 6-car trains. On the 29 January 2007, Connex cancelled 37 peak-period services until further notice, due to the shortage of operational trains.
By the 1st of February, 38 three-car sets were withdrawn due to continuing braking failures, meaning that almost half of the Siemens fleet (or around ten percent of the total fleet) was out of revenue service. Amidst the media reporting an escalating problem with the risk of the entire fleet potentially having to be suspended, Siemens issued a statement on 31 January saying that they believe there has been no evidence during investigations of the braking failures that would require the entire fleet of trains to be withdrawn from service. The entire fleet has now re-entered service, although with a restriction on single unit (3 car) operations.
The version of Siemens metro train designed for Melbourne included several attributes similar to existing Melbourne suburban electric trains such as being single-deck and operating in M-T-M (motor-trailer-motor) sets of three carriages, where the motor cars each have an overhead pantograph, and two of these 3-car sets are generally coupled together to form a 6-carriage train when run in revenue service, though a single set may be run when demand does not merit a full train. Each 3-carriage set can carry 522 people and is 71.9 m in length.
There are several notable differences between the Siemens trains and other trains which operate in Melbourne. These include:
The Siemens train are fitted with a Passenger Information Display system (PIDS) produced by the German firm Annax. The system is unique to the Melbourne rail network, as it uses the original M>train voice of English dialect, and does not announce express running or the end of services. The external destination indicators are large in size compared to other Melbourne trains. New announcements that are said by the ALSTOM voice are slowly beginning to be installed to Siemens trains for North Melbourne, Craigieburn and Roxburgh Park stations since the Craigieburn Electrification Project was completed in mid-2007.
The trains were originally delivered with M>Train blue and green stripes on the side, and the M>Train 'swirl' on the front fairing. Later deliveries entering service in bare metal on the sides, and white front fairings with a green and yellow striped bar. On entering Connex ownership blue and yellow stripes were progressively added to the side of all trains, and front fairings were repainted yellow with the blue Connex logo.