The pledge came as the deadline was reached for submitting bids for the 15-year franchise. Two other groups have put in bids - James Sherwood's Sea Containers, which operates the East Coast Mainline, and Stagecoach, which won the SouthWest Trains franchise.
The bidders were each required to submit two bids - one involving tilting trains and the other based on refurbishing the existing trains or replacing them with conventional rolling stock.
Virgin, which is buying pounds 250m worth of rolling stock for its Cross Country Trains franchise, said its preference was for the tilting train option.
Railtrack has already undertaken to spend pounds 1.3bn upgrading the line in any event and will invest a further pounds 150m if the Government's franchising director, John O'Brien selects a bid using tilting trains.
The plan is to cut journey times so that London-Manchester would take only two hours, 30 minutes faster than at present. This could be achieved either by using tilting trains which need to brake less or by straightening parts of the line. The new rolling stock is due to enter service in 2002.
Although arguably Britain's prestige line, the West Coast mainline is heavily loss-making. It is receiving a subsidy this year of pounds 92m compared with revenues of pounds 219m a year. Its rolling stock is among the oldest on the rail network.
Despite the failure of British Rail's Advanced Passenger Train, which also featured tilting technology, and the crash in Italy earlier this month of a Pendolino tilting train with many fatalities, these trains have the best safety record of any modern rolling stock. They are in use in eight countries on the Continent including Germany, Portugal, Spain, France and Switzerland.