South Western Railway has unveiled a £1bn new fleet of trains at an event in London Waterloo Station this morning, following half a decade of delay.

The operator is bringing into service 90 Class 701 Arterio trains, manufactured by Alstom in Derby.

However, the fleet is some five years behind schedule following a protracted dispute with unions over its safety, and a number of separate faults.

The Rail Maritime and Transport Union (RMT) held two months worth of strikes in a dispute over the role of train guards and drivers on the service.

Faulty software also left many of the trains unused and stored in sidings for years.

Reps from Aslef, the train drivers union, also raised concerns over the size of the Arterios’ windscreen wipers earlier this year, claiming it blocked drivers’ view of trackside signals.

A “development” service had been in operation, with five Arterios already serving routes to Windsor and Eton Riverside and Shepperton. A first train began running in January this year, operating a single round trip during off-peak hours, between Waterloo and Windsor.

Stuart Meek, Interim Managing Director for South Western Railway, said the new rolling stock would “completely transform every single journey on our suburban network.”

“Over the next six months, Arterios will call at 74 stations, operating 80 peak services every weekday, with customers along new routes including Dorking, Epsom, Guildford, Hampton Court and Reading able to enjoy extra capacity and comfort.”

Speaking to reporters at the event, Meek admitted the trains wouldn’t solve “perennial issues” with track infrastructure and signalling, which have caused a string of delays and cancellations in the last year.

Each ten-car Arterios carries around 50 per cent more customers than the eight-car Class 455 trains they replace.

The new fleet will also serve stations including Dorking, Epsom, Guildford, Hampton Court and Reading over the next six months.

Some 750 drivers are being trained to operate the new service.