Rail workers could soon be voting on strike action to protect their pension scheme.

Leaders of the RMT warned they will fight proposals by Network Rail to close its final salary pension scheme to new entrants.

General secretary Bob Crow said his union would consider a strike as a "last resort" if bosses go ahead with the plan.

The scheme includes staff not only from Railtrack's brief tenure but also people who began paying in as British Rail employees before privatisation.

Burgeoning pension commitments for the firm have been caused by people living longer, poor stock market performance and the decision by Railtrack to offer early retirement to many older employees in a bid to save cash.

The pensions issue is adding to the problems for Network Rail which is battling to find the extra billions of pounds needed to upgrade parts of the rail system.

The company, which replaced Railtrack as the controller of Britain's troubled rail network, is set to give its final decision by the end of March.

But Crow condemned the proposal as "scandalous", warning it would simply add to a two-tier workforce.

"We all appreciate that there is pressure on companies to close schemes down," he said.

"But with all the money that has been paid into the railway network, we find it absolutely scandalous that from April 1 next year, people coming into the industry will have a worse pension ... people are being totally thrown to the wolves."