Journey into the age of the 140mph train

Travellers on a morning rail service from Ashford in Kent to central London might have been forgiven for thinking they had been transported to another country yesterday.

For a start, there was space – lots of it. No more cheek-by-jowl commuting here; there were even spare seats. And then there was the speed. Rather than the usual stopping and starting, on this train you could hardly see the countryside as it whizzed by. "I'm used to having enough time to get settled and have a look through the papers – I'd only managed a page or two before it was time to get off," said one passenger.

Welcome to the future of British rail travel. This was the first high-speed "Javelin" train to rocket down the new St Pancras-Ashford line at speeds of up to 140mph. Rail operator Southeastern began running previews of the service yesterday, which will slash journey times by as much as 43 minutes by using the same high-speed lines as Eurostar.

But there is a catch. Passengers will have to pay more than they would do for slower journeys. A single fare from London to Ebbsfleet on the Javelin trains costs £12.20 instead of the usual £9.10, while London to Ashford will go up from £22.20 to £26.60.

Southeastern will not launch its full marketing campaign for the service until early next month, meaning those in the know so far are enjoying a little extra legroom – and overcrowding may yet return. Southeastern said a possible 200 extra trains a day could be running from December.

While yesterday's maiden service arrived at St Pancras one minute early, this being Britain, there were a few teething troubles. One elderly passenger was forced to buy a "16-25 years" ticket after the machine refused to dispense anything else.

The first passengers also warned that others may need to bring their sea legs. The Hitachi-manufactured train appeared to sway from side to side, unlike conventional rolling stock, which could lead to intimate situations as the trains fill up.

Vince Lucas, commercial director of Southeastern which operates the line, said: "This preview service is aimed at ironing out any creases that may exist. Around £5.8bn has been spent on laying and upgrading the track and we need to know about those mundane problems which routinely slow passengers down now, before we start running a full service in December."

Charles Horton, managing director of Southeastern, said, "While it is an important day for the industry as a whole, we have been careful to not lose sight of who it is really for – the passengers."

Andrew John, a 45-year-old chartered engineer, said of the new service: "I can get from St Pancras to Kent quicker than some Londoners can get about on the Tube."

There will be 29 of the trains in operation from December 2009. At present, the Javelins are only running as far as Ashford, but by the end of the year they will help reduce journey times to towns all over Kent from London. St Pancras to Canterbury will take 59 minutes, Folkestone 57 minutes and Ramsgate 80 minutes.

In 2012, the Javelin trains will also take spectators from St Pancras to the Olympics site at Stratford, east London, in only seven minutes.