The fleet of 115 dual-voltage (750V dc/25kV ac) 160km/h EMUs will be supplied as 55 12-car sets, each seating up to 666 passengers, and 60 eight-car trains, which will seat 427.
Trials using Automatic Train Operation will be carried out on the Hertford Loop north of London later this year.
Construction of the depot at Three Bridges will be completed in July, while the depot at Hornsey north of London is due to be completed next year.
So far Siemens has completed assembly of six 12-car and one eight-car trains at Krefeld and dynamic testing is underway at the company's test centre in nearby Wildenrath. By February 2016 the Krefeld plant will roll out two class 700 vehicles every working day, and the entire fleet will be delivered by June 2018.
Testing began at Wildenrath in March 2014 and is expected to be completed in July this year. The first trains will be handed over to operator Govia Thameslink Railway (GTR) in December and will enter service on the Brighton to Bedford route in February 2016.
A full description of the £6.5bn Thameslink upgrade and the new train fleet can be viewed here.