The two areas have been shortlisted by Hitachi, which is part of a consortium provisionally awarded the contract by the Department of Transport.
At a cost of around £7.5 billion, the development would see the creation of 800 manufacturing jobs as a project to build faster, greener trains that can carry 21 per cent more passengers.
John Laing is one of Hitachi's partners in the plans and would be responsible for building maintenance centres.
The Agility Trains Consortium consists of the two companies plus Barclays bank and was selected to take on the project in February, a spokeswoman for the Japanese firm said, however it is uncertain whether or not the plans will now go ahead.
Explaining that the investment could be cut during the leaders' spending review, she commented: "The government is looking at every contract like this ... we are looking forward to a positive result," according to the BBC.