PLANS for new state-of-the-art trains to stop at a Hampshire station have been put back on track after they were derailed because the platform was too short.

South West Trains ran into trouble over introducing the Siemens Desiro 444 electric trains as a high- speed London connection when they realised that Portchester station wasn't big enough.

It meant that some of the automatic sliding doors on the train would open short of the platform leaving passengers facing nothing but a drop onto the track.

Now Network Rail who initially estimated the extension would cost £725,000 have completed a major recalculation and slashed the cost to under £100,000.

Work is due to begin in January and will take about two months after which the brand new trains, which replace slam door rolling stock dating from the 60s, will provide a regular service.

A spokesman for Network Rail said that more than £600,000 had been knocked off the bill for the work because signals did not need to be moved and efficiency savings had been made.

He said: "The initial estimate was made in 2002 when rail track were in operation. Since then we have introduced a programme of efficiency savings which have helped to reduce the cost."

A spokesman for South West Trains said: "We are delighted with the news, it means we will now be able to continue serving Portchester with the new trains."

The Desiros will go on line in December. Soon after they will provide a service from Portchester although doors that do not open onto the station will remain closed.

The new trains are air conditioned, safer, more comfortable for passengers and have better on-board passenger information systems.

A spokesman for the Strategic Rail Authority said both sides of Portchester station would be extended by six or seven metres.