The option is part of a Forints 9.2bn ($US 29.6m) contract originally agreed in 2017 for the supply of eight units to be delivered by autumn 2021.

The low-floor units, which are to be manufactured at Stadler’s site in Valencia, Spain, will have 92 seats with a total capacity of 220 passengers, including four multi-purpose places for wheelchairs and prams. In addition, they will be equipped with air-conditioning, security and passenger information systems.

The tram-trains can operate both in electric mode through a 600V dc overhead power supply on urban tram networks, and in diesel mode using low-emission 390kW engines on the main line railway connecting the two cities.

The new units will allow uninterrupted travel between the two systems and are planned to run every 15 minutes, providing a high quality commuter link for workers in both cities.