TAYLOR Woodrow is heading the race to build three train depots in Manchester, Northampton and York worth £50 million in total.
German engineering giant Siemens is building the facilities to maintain 30 new Desiro trains, due to be introduced on the network next summer.
The trains will replace old stock on routes used by Silverlink, which operates services between London and Birmingham, and Central Trains, whose network stretches from Cardiff up to Liverpool and across to Norwich.
Siemens has signed a 20-year maintenance contract to look after the four-car trains.The Desiro trains were originally designed for use by South West Trains but their introduction here has been delayed by a year because of power problems.
Sources close to the deals said Amec, Fitzpatrick, Nuttall and Mowlem are all lagging behind Taywood in the battle for the first £21 million project in Manchester.
One insider said: 'There won't be any firm decision for a couple of weeks, but it is 99.9 per cent Taywood's.'
The same group of contractors are thought to be bidding a second, slightly larger job in Northampton, with a possible third £6 million facility in York also up for grabs.
Competition for the £25 million Northampton deal is still neck-and-neck.
But one insider admitted: 'The latest rumour is that Fitzpatrick has the inside line on this.'
It is unclear whether the York contract will be tendered or negotiated with the winner of one of the other deals.