New modernised trains have come into passenger service on Glasgow’s subway.

The launch is part of a £288m upgrade programme of the city’s underground rail system.

The first two trains were introduced by Strathclyde Partnership for Transport (SPT) without fanfare on Monday.

They will run alongside existing services on the circular route, connecting 15 stations around Glasgow.

In total 17 trains will be gradually brought into service during 2024.

They will eventually replace the current stock as the older carriages are retired.

It comes after a two-year testing period that included partial subway closures.

The new trains are the same length as the older carriages, but feature a “walk-through” design, are wheelchair accessible and air conditioned.

SPT said the trains should be more comfortable and quiet.

The trains also have the capability to be driverless, which the operator aims to introduce in future.

Further technical changes are needed including changes to the subway’s navigational systems and the creation of a new “operational control centre”.

SPT will also introduce platform screen doors to station platforms.

Project director, Mark Toner said: “This is a brand new, complex state-of-art system going into a very old network and that does, frustratingly, take time to deliver.

“We are still some way off seeing platform screen doors added to all stations which will be the next big thing for passengers before we have the option of moving to driverless trains,” he said.

SPT said that once the modernisation project was complete, more frequent trains could be introduced based on customer demand.

Mr Toner added: “Our old fleet has performed beyond its expected lifespan and it has become more and more challenging to maintain them and find parts for them.

“The new fleet will take time to grow towards full capacity and reliability.”