The UK Department for Transport (DfT) has unveiled plans to invest £8bn ($12.6bn) to upgrade the nation's rail infrastructure by May 2019.
The investment will be used to continue electrification works and add more than 2,100 rail carriages.
The carriages will be introduced on the Thameslink line and in-construction Crossrail services, as well as another 300 new carriages to be provided for other franchised train operators.
The DfT confirmed 1,200 new electric vehicles for the Thameslink project and is considering bids from two consortia led by Siemens and Bombardier Transportation UK; a preferred bidder will be announced in spring 2011.
The department said it will replace existing intercity 125 high-speed trains, while existing electric trains from Thameslink will be able to be deployed elsewhere on the rail network.
The DfT also confirmed the electrification of the Great Western route lines from London to Didcot, Newbury and Oxford as well as between Liverpool, Manchester, Preston and Blackpool.
A further statement about the Intercity Express Programme will be made next year, although the department said it is concentrating two options which include a revised bid from Agility Trains, and an alternative for a fleet of all electric trains.
The preferred bidder for the Intercity Express Programme is Agility Trains, a consortium consisting of Hitachi Rail Europe and John Laing.