The discount will apply only to the first 800 shares they are allotted in the flotation in May, and they must hold them continuously until the payment is made. Alternatively, investors may opt for a one-for-15 share bonus on their first 1,200 shares.
The second instalment date will be announced on Monday with the prospectus, but SBC Warburg, global adviser to the sale, has already said it will be in the 1997 financial year, so that payments can be made in two financial years, doubling the amount that can be put into Peps.
The 15p discount is separate from a promised discount to the offer price when the issue is sold in May. Retail investors will be given a lower price than City and overseas institutions pay.
The Government is planning to sell a minimum 51 per cent of Railtrack, with at least 30 percent of the shares intended to go to individual retail investors as part of incentive-based packages.
The pathfinder prospectus is expected to announce a sale of 100 per cent of Railtrack. Railtrack shares are expected to offer a dividend yield in the region of 7 per cent.
London loan market sources said Railtrack had agreed the pounds 2.35bn loan it needs for its core future financing with a syndicate of eight banks led by Barclays Bank's BZW Syndications.