A tender for the contract will be launched early next year and the first pre-series vehicles are due to be delivered in 2018, with BSAG set to receive production vehicles from 2019 onwards.

BSAG has an urgent requirement for different vehicles, which has resulted from a combination of factors. The fleet of 77 GT8N LRVs supplied by AEG in the 1990s initially covered an average of around 50,000km per year and had a design life of 25-30 years. However, with the vehicles now averaging around 71,000km, the fleet has reached life expiry much sooner than originally envisaged.

The GT8N was also a very early low-floor design and was delivered at a time when manufacturers had little experience of such vehicles. Above-average stresses have therefore limited their useful life and in recent years there has been an increase in stress-related component failures, which have reduced availability.

According to the Senate, the network has grown by 15% since 1995, but the fleet has been reduced from 150 to 120 vehicles over this time to reduce maintenance and financing costs. In addition, low-floor vehicles have been used more intensively to ensure compliance with legislation on accessibility for passengers with reduced mobility.

"Trams are very important to the public life and economy of this city," says Bremen's transport senator Mr Joachim Lohse. "Smooth operation must be guaranteed, so this is a good investment in the future of Bremen."