The 200mph train operated by Germany's state railway company, Deutsche Bahn (DB), was at St Pancras station for an event due to be attended by the transport minister, Theresa Villiers.
It arrived at St Pancras after a safety exercise in the Channel tunnel. The state-of-the-art, German-made, Inter City Express (ICE3) train must pass stringent tunnel safety tests before it can start full services from Frankfurt to London, with December 2013 the likely start date.
DB is considering a route that would start in Frankfurt – the heart of Germany's finance industry – with possible stops at Cologne and Brussels en route to London. The service is expected to grow the high-speed rail market between London and the continent by around 10%, carrying more than 1 million passengers per year.
The service would stretch the industry maxim that rail journeys must last no longer than four hours in order to compete with airlines.
A trip between Europe's two largest financial centres would take four to five hours, with DB hoping that the appeal of broadband access and lack of airport security hassle will tempt the all-important business traveller market.
Channel tunnel safety authorities have already relaxed regulations that will make it easier for DB to operate a London-to-Frankfurt service.
Trains using the Channel tunnel have to be 375m long as that is the distance between the emergency exits in the tunnel that connect with the central service tunnel used in the event of emergency evacuations.
The ICE3 trains are not that long so two would be bolted together for the journey through the tunnel. But that would mean passengers could not travel through the length of the train, so DB has to prove that this would not be a hindrance and show that it can evacuate people from either end without serious problems. There have been three fires in the tunnel since it opened in 1994.
The service could use the high-speed terminal at Stratford in east London to tap the business market at Canary Wharf and in the City, according to High Speed One, the owner and operator of the Channel tunnel rail link.
Eurostar, the Paris and Brussels service that operates from St Pancras, has been a success since its 1994 debut, now carrying more than 9 million passengers and taking three-quarters of the air and rail market between London and the French and Belgian capitals.