The first two new trains are said to be ready to “roll off the production line” in Switzerland.
These trains will go through their paces at a larger test track in the Czech Republic.
According to Metro, the first new train is anticipated to reach North East England prior to the end of 2022.
Nexus depot renewal and fleet head Michael Richardson said: “I’m delighted to say that the first couple of new Metro trains are complete and are about to roll off the production line over in Switzerland.
“Stadler will then need to put the trains through a testing phase which will take a few months.
“Once that is complete the first new Class 555 Metro train will be ready to be brought over to the UK, which will be a historic moment for the Tyne and Wear Metro and for our region.
Stadler is constructing 46 new Metro trains for Nexus, which are expected to be delivered up to 2024.
These trains feature new carriage interior, seats, and handrails, as well as the new iconic Metro logo.
With an ability to lower energy usage by 30%, the new trains also include charging points, air conditioning, and a step-change in accessibility.
Besides, the trains include an automatic sliding step at every door to facilitate easy travel for Metro’s 50,000 wheelchair passengers and people with children’s buggies, luggage, or bicycles.
This year in June, Nexus concluded the second phase of work on the new £70m Gosforth Metro depot in the UK.