But in a trip that demonstrated how the service could revolutionise travel between Britain and its near neighbours, a spare train ran through to the French capital in a record-breaking journey of just under 2 hours 49 minutes, 11 minutes ahead of the three-hour schedule.
The fault on the first Eurostar train, which was supposed to be taking 400 journalists on the first public outing of the service, was caused by a faulty circuit- breaker on the mechanism that switches power between the different systems used in France and Britain.
The service to Paris and Brussels is due to start operating on 14 November with two trains a day to each capital, building up to 15 trains a day by the end of next year.
Return fares range from pounds 95 for passengers booking two weeks in advance to pounds 195 for first-class travel.
Yesterday's technical mishap is a bad public-relations blow to a service that is likely to provide a strong challenge to the airlines on short-haul routes across the Channel. Fortunately, the inaugural train from Paris to London ran flawlessly.
Once it started, the journey was incredibly smooth broken only by cursing between the railway buffs and other journalists. The chaps from the railway magazines were livid as they heard the other journalists dictating their knocking copy about 'red-faced railwaymen' into their portable telephones.
Peter Fox, the publisher of Today's Railways, muttered into his notebook 'Why are they always complaining? This is a fantastic train. They ought to have a good word to say.'
He was right about the train. Even the Kent countryside was passed at 100mph and the tunnel was but a 20-minute blip. Once the train reached France the acceleration to 186mph was palpable, like being in a jet on the runway.
The technical problem is the latest in a series of faults that have delayed the introduction of the service.
The complexity of the power system is at the heart of all the problems. The Eurostar trains are the most complicated built as they have to be able to draw power from three different types of system: the third rail in England and two different types of overhead supply in the tunnel and in France.
The root of the difficulties is the Treasury's refusal to allow British Rail to install overhead electrification on the lines that Eurostar trains share with Kent commuter trains, and the dithering over the high-speed rail link, which will now not be ready until 2002 at the earliest.
The fact that the Eurostar trains will have to share the track with Kent commuter trains until the new line is built is the biggest problem facing the new service, as it is likely to make it difficult to achieve the reliability necessary to attract regular travellers.