Transport for Greater Manchester has started the formal process of appointing the operator-maintainer for the tram for seven years after 2017.
TfGM tender papers show a budget of between £300m and £830m for the contract term.
The contract will run from July 2017 for a term of seven years with a potential extension of up to a further three years. The successful contractor will be responsible for both the operation and maintenance of the Metrolink system.
TfGM said in the invitation to tender: "The Metrolink system is the largest tram network in the UK and is of strategic importance to the economy of Greater Manchester as it provides fast and frequent links across the Greater Manchester region supporting employment, leisure and tourism. By 2017, following completion of the phase 3 expansion project the system assets will comprise a fleet of approximately 120 trams, 180 km of track and overhead line, 93 stops, and 44 substations; two operational depots; and a patronage of approximately 40 million journeys per annum. In addition to the existing assets, during the proposed contract term the system may be extended to include at least one additional line and associated infrastructure which may include but not be limited to trams, track, overhead line, stops, and substations."
The planned new line will link intu Trafford Centre with the city centre.
Currently, system maintenance is the subject of two separate contracts. Maintenance obligations for the tram fleet and phases one and two of the system are included within the combined operations and maintenance agreement with Metrolink RATP Dev Limited, which is also the operator for the whole of the system. The maintenance obligations for phase three infrastructure are delivered under the design, construct and maintain contract with the M-Pact Thales consortium, which is the contractor for the phase three extensions.
It is TfGM's intention that the operation and maintenance for the full system, which may extend to maintenance not currently provided for in the agreements with MRDL and MPT, will be delivered under a single contract.