TENS of thousands of commuters face a "disastrous" four-day rail strike on the area's most important rail lines.

Drivers union Aslef has written to South West Trains saying it plans action from March 31 to April 3.

All services on the vital Weymouth-to-Waterloo route would be affected, plus dozens of other services.

Crunch talks are due today but plans are being put in place to run massively reduced services and replacement buses.

John Thomas, chairman of Purbeck Transport Action Group, said: "This is a return to the old days - it's a disaster. So many people around here rely on trains."

An Aslef spokesman said South West Trains' decision to release details of the strike notification was "a clear indication of what management wants from these discussions - failure".

A South West Trains spokesman said: "We couldn't sit on our hands and hope it would be cleared up."

Commuters could turn to Virgin Cross Country, but it only operates one train an hour to Clapham Junction from Bournemouth, and one an hour to Portsmouth and Southampton.

South West Trains said it had offered a 4.5 per cent pay increase, giving London-based drivers a basic salary of £40,447 for a 37-hour week.

An Aslef spokesman declined to say what increase it was asking for. The union estimates its 18,5000 union members include 95 per cent of drivers.

The news had passengers at Bournemouth railway station fuming last night.

Graham Collings, 51, a housing association officer who commutes from New Milton to Bournemouth, said: "Before there's a strike they should get the trains working properly. They never run on time, the heating doesn't work, and you don't see an increase in service as fares go up. This is the kind of thing to make you think Damn it, I'll just drive'."

Matthew White, 39, from Bournemouth, who has a sports marketing company in London, said: "Lots of people commute two or three days a week to London. I go once a fortnight. Four-and-a-half per cent is not bad. They should be glad to have a job."

Cllr Ron Whittaker, from Bournemouth, a former footplate fireman, said he once worked during a strike because he did not agree with it.

He said: "There are times when individuals have to stand up for themselves."

He added: "We need to get management and the drivers in a locked room. They will lose so much money through a strike."

A taxi driver at Bournemouth station said: "It will be a tremendous blow - if people don't travel by train, business from the station goes down by about 80 per cent."

Cllr Robert Lawton, Bournemouth's cabinet member for transport, said: "It is extremely upsetting to hear about the strike action. It is unfortunate that they feel they must take this action."