The grey ICE3 train, made by Siemens of Germany and operated by Deutsche Bahn, entered at the French end of the tunnel near Calais, watched by reporters.
The German operator wants to demonstrate its ability to run safely on the route, which is being opened up to competition under European Union rules, to the annoyance of France, which has so far dominated cross-Channel traffic.
France, which owns 55 percent of the cross-Channel Eurostar service, last week reacted angrily to the company's decision to buy trains for the route from Siemens instead of from French engineering company Alstom.
The ICE on Wednesday was the first passenger train not run by Eurostar - an operator jointly owned by France, Britain and Belgium - to use the tunnel, running into it at 30 kilometres (18 miles) per hour.
Carrying drivers and technical staff from Germany's Deutsche Bahn and tunnel operator Eurotunnel, but no passengers, it went part of the way through the tunnel before turning back and re-entering France after 10 minutes.
It is to return to the tunnel for safety drills on Saturday and then travel, towed by another engine, all the way to London next week.
About nine million passengers now take the train each year on Eurostar routes between Brussels, London and Paris.
France's Ecology Minister Jean-Louis Borloo and junior transport minister Dominique Bussereau last week attacked a decision by Eurostar to buy 10 Velaro high-speed trains from Siemens, shunning Alstom.
They and Alstom said the Siemens train did not meet the safety requirements for the tunnel. Trains passing through it have to be long enough to allow passengers anywhere on board to reach emergency exits in the tunnel.
Eurostar trains based on Alstom's TGV model are 400 metres (1,300 feet) long and escaping passengers can be sure of being able to exit near a safety tunnel.
Deutsche Bahn wants to run pairs of 200-metre ICE trains in tandem, while Eurostar wants a new version designed to meet the 400-metre requirement.
This Velaro train, Siemens's new generation successor to the ICE3, can carry up to 900 passengers, or 20 percent more than the tunnel trains now in circulation, at 320 kilometres (200 miles) per hour.
It would connect London and Paris in just over two hours, London and Amsterdam in less than four hours, and London and Geneva in about five hours.
Siemens, a vast engineering conglomerate, has had ambitions for years to challenge the French TGV high-speed trains made by Alstom, which have gained a big lead in European and world markets, with models of its own design.
In 2012, Deutsche Bahn plans to offer services to London for the Olympics, meaning that for the first time two European railways will compete on a cross border route.
The French ministers said they supported opening EU railways to competition but stressed safety concerns, citing fires in the tunnel in 1996, 2006 and 2008. German officials have accused France and Britain of protectionism.