The fleet of Midland Metro Urbos 3 trams are to be fitted with hi-tech batteries to power the vehicles through architecturally sensitive areas.
It also means the planned Birmingham Eastside extension running under the proposed HS2 station at Curzon Street will not need expensive infrastructure works to accommodate overhead lines.
Cllr John McNicholas, chairman of the ITA's delivery committee, said: "When we placed the order in 2012 for our new fleet of trams the ITA had the vision for them being capable of running without overhead wires.
| How catenary-free trams would look running through |
Birmingham’s Victoria Square
"That is now the case and the application of battery technology on this scale in the West Midlands will be a historic first for the UK light rail industry and the modern era of British tramways."
The current 21 tram fleet was made in Spain by CAF.
Urbos 3 trams already run catenary-free in sections of the tram networks in Zaragoza, Seville and Cadiz in Spain but use supercapacitors to provide on-board energy storage.
However these would be unsuitable for trams negotiating the steep hill in Pinfold Street from New Street station into Victoria Square.
Overhead lines and equipment would have been needed, marring the architecturally sensitive environment of Victoria Square.
However CAF now says newly available lithium ion batteries are robust enough to handle the gradients and can be fitted so trams are ready to run when the extension to Centenary Square opens in 2019.
The batteries will be fitted on the tram roof and will be recharged by the overhead lines along other parts of the route.
They are expected to require replacement at approximately seven-year intervals.
Four new trams to allow the fleet to keep the current level of service once the Centenary Square extension opens have already been ordered and will come with batteries fitted.
There are four sections identified in future network extensions for catenary-free running:
- The whole of the Birmingham Centenary Square extension, including through Victoria Square, where the Town Hall and Council House are situated
- The Birmingham-Edgbaston extension from Centenary Square to the Brindleyplace tram stop, and through the underpass at Five Ways
- Birmingham Eastside extension between Moor Street Queensway and Digbeth High Street stop, including under the proposed HS2 station at Curzon Street
- Wolverhampton city centre extension between the bus station and the railway station tram stops, encompassing the main pedestrian approach to Wolverhampton Interchange
This includes the Birmingham Eastside section where the extension runs under the proposed Curzon Street station along New Canal Street.
The lack of headroom under the new station and the existing West Coast Main Line bridge would have meant major works to lower the road to install overhead lines - work which will now not be needed thanks to catenary-free running.
Negotiations have begun with battery suppliers but the final cost is not yet available.
However a £3.15m contribution will be made by the Greater Birmingham and Solihull Local Enterprise Partnership and £1m will come from industry association UKTram.