According to the Financial Times, Eurostar chose
Siemens as preferred bidder over Alstom's AGV in June, although the
operator declined to comment on the details of the deal, which is
expected to be worth around Euros 600 million. The trains will be 400m
long to satisfy Channel Tunnel safety regulations, which stipulate a
minimum train length of 375m.

German Rail is also planning to launch direct services from London to
Frankfurt using 200m-long ICE3 high-speed trains operating in pairs.

However, the Financial Times also reports the French government is
planning to block the use of trains with distributed power inside the
tunnel, which would preclude the use of most modern high-speed train
types, including the Velaro.