Alstom's Metropolis family of
electric multiple units is highly adaptable; the basic body can significantly vary in size between small, medium and wide configurations to meet a variety of client's needs. A typical trainset is deployed in a two- to six-car arrangement. The Metropolis has been designed to be both flexible and reliable, incorporating a high level of technology to do so. It has been designed for a maximum speed of up to , which has been deemed to be sufficient for its use on mass transit systems. The propulsion system incorporates the ONIX (ONduleur à Intégration eXceptionnelle) or OPTONIX
VVVF drive with
IGBT transistors that control asynchronous three-phase alternating current (AC) traction motors. Amongst other abilities, this arrangement enables
regenerative braking, reducing the train's energy consumption. It can be configured to operate as part of an entirely automated driverless system, enabling the train to have unattended train operation (UTO) functionality. To achieve this, Alstom typically offers the Metropolis as one element of a complete turnkey system, including the trainset itself along with the signalling system, track works and services. Several operators have procured the train in such a configuration, including the
Sydney Metro (Australia's first fully-automated rail network) and the
Budapest Metro (the first automated metro line in Central-Eastern Europe). The car body is highly adjustable, being composed either of
aluminium or
stainless steel, while the width can range from and the length from . It can be fitted with either
steel wheels or
rubber tyres, depending upon the customer's requirement. As standard, each Metropolis features a trainborne
Ethernet backbone, providing resilient broadband communications for subsystems, including security apparatus, an optional public address system, and passenger information equipment; these are organised into integrated modules within the onboard security and communications subsystems. For ease of maintenance, the Metropolis is compatible with an internet-delivered
TrainTracer tool, which monitors major components of each train and can display condition information in real-time to depots and operational control centres alike. The interior can also be customised as per customer requirements. Optional features include
closed-circuit television (CCTV), wider seats, additional grabpoles, more space around the doors, wheelchair space and equipped with electronic displays – the latter is typically used to depict journey information, safety messages and advertisements. The size of the doors can be customised along with the width of the gangways, while a
modular seating arrangement is typically installed. A specialised glass named
Climavit is used for the windows, it is supplied by the French manufacturer
Sekurit Saint-Gobain; amongst its claimed benefits is a reduction in the typical internal noise level by five
decibels. == Major deployments ==