The bill for damage on the short Romford to Upminster branch line in Essex was pounds 60,000 last month alone, despite the efforts of British Transport Police to control the problem.
A British Rail spokesman said the move to suspend the majority of services because of vandalism was rare. It is the first time Network SouthEast has planned to cut services in such circumstances. The company says withdrawing off-peak trains from next month will allow it to concentrate police officers on rush-hour traffic.
In recent weeks children have wrecked two new automatic ticket machines costing pounds 16,000 each, ripped out 'hundreds' of seats and thrown them on the track, sprayed carriages with foam from fire extinguishers and thrown the canisters from the train, and even set fire to trains. A spokesman for Network SouthEast said most damage occurred when children were travelling to and from school.
Sergeant Kevan Sharp of the transport police said there had been a number of arrests in recent months on the route. Most were juveniles.
'No matter the effort we put into a line just three miles long, we have horrendous problems trying to stop this. If you walk alongside the track every 10 yards or so you will find a seat cushion.
'A lot of work has gone into that line in comparison to the manpower I have. I have been putting men on trains. It is a deterrent when they are there but I have not got the manpower to be on every train.
'We have had no information from the community about what is happening and that is very disappointing. I have no idea why we have this level of problem in this particular part of Essex but it is a real thorn in our sides.'
A Network SouthEast spokesman said: 'It is a matter of getting the message out to parents of the children responsible. They will have to make alternative arrangements for their children travelling to school if this does not stop.
'But it is not just the kids. Adult passengers are not doing anything to stop it. They are either putting it down to youthful high spirits or they just don't want to get involved. But this situation has reached an acute state.
'People have said this is a precursor to closure of the line. That is untrue. However this line is not economically viable enough to sustain this level of cost for vandalism.'
Network SouthEast proposes to run two trains an hour for the rush-hour to meet legal requirements.