The new trains were built and tested in Switzerland, after which eight train drivers travelled from north-east England to test them in the Czech Republic.
According to the BBC, the new trains are planned to go into service in the autumn of 2023 and will include features like linear seating, wi-fi, phone charges, air conditioning and better access for wheelchairs.
Nexus, the operator of the Metro, spent £362m on a fleet of 46 new Stadler trains. The new models are set to replace the old that have been used since the network first opened more than 40 years ago.
According to the BBC, Craig Pearson, a Metro driver for 10 years, has been one of the first to try the new trains and said: “Everything is at your fingertips in the new drivers' cab."
"The layout is better and the computerised control systems are amazing. It's a huge jump from analogue to digital technology.
"The new train is very smooth, quiet, and comfortable to drive and will undoubtedly improve our working environment."
Head of the fleet at Nexus, Michael Richardson said there were 177 drivers who had to undergo training on the new trains.
"Everyone will get time in the special simulator ahead of driving one of the new trains on our network for real," he added.