* Hopes to run services from London to Frankfurt by end-2013
* Gets British, German government, Eurostar support
* Alstom says has filed legal complaint against Eurostar
(Adds Eurostar comments, Alstom legal complaint)
By Greg Roumeliotis and Caroline Copley
LONDON, Oct 19 (Reuters) - Britain, Germany and rival Eurostar all backed Deutsche Bahn's bid on Tuesday to run direct high-speed rail services from London to continental European cities through the Channel Tunnel, as a dispute over what trains could use the tunnel intensified.
The German rail operator, which was showing off one of its trains at London's St Pancras station on Tuesday, aims to run services three times a day between London and Amsterdam and Frankfurt and hopes to start services by the end of 2013.
Eurostar, the sole passenger train service operator running trains through the tunnel since it was opened in 1994, supports Deutsche Bahn's move, saying it is another step in the expansion of high-speed rail travel across Europe.
"We welcome Deutsche Bahn's plans, we want them to help us grow the rail passenger market together," Eurostar's chairman Richard Brown told Reuters at the presentation of Deutsche Bahn's plans at St Pancras.
Deutsche Bahn had an ICE 3 train, a member of Siemens's Valero series, which can hit 320 kilometres per hour, on display at St Pancras station following what it called successful safety tests.
ALSTOM LEGAL ACTION
But Brown said French train maker Alstom has threatened legal action over Eurostar's decision to pick Siemens as preferred bidder for a 700 million-pound order for new cross-Channel trains.
Alstom and the French government have been vocal in opposing Eurostar's preference for the Siemens trains, alleging there are safety issues with using Siemens trains in the Channel Tunnel.
"They (Alstom) have threatened action against us in the UK courts. As a result I cannot comment on this further," Brown said. Asked if Alstom had communicated this threat to Eurostar through its lawyers, Brown answered "yes".
"There is no safety issue. We followed a thorough and comprehensive procurement process in line with EU regulation and with board support," he added.
An Alstom spokesman said the company had filed a complaint at a London court against Eurostar over the Siemens order but declined to give details.
"There is no really substantial argument against the Siemens (train) technology," German transport minister Peter Ramsauer told reporters at the St Pancras presentation, adding he would discuss the issue with his French counterpart in Paris on Wednesday.
The Franco-British Intergovernmental Commission (IGC) governing the operation of the Channel Tunnel is reviewing regulations, such as those for trains that have a traction system under their carriages, removing the need for locomotives at each end.
On Monday, a European Union source told Reuters that the European Commission saw nothing wrong with Eurostar's procurement process for the trains and that Alstom had not officially referred the matter to European authorities.
"Our ICE 3 trains are very similar to the Valero trains that Eurostar has ordered from Siemens, they are from the same production line," a Deutsche Bahn spokesman said. Deutsche Bahn has ordered 15 ICE 3 trains from Siemens for 500 million euros.
"The issues we will need approval for is distributed traction and allowing our trains to split." he added.
One 400 metre-long train would travel to Brussels and then split with one half going on to Amsterdam and the other half travelling to Frankfurt via Cologne.
GROWTH POTENTIAL
In 2009, Eurotunnel made 44 percent of its 571 million euros revenue from Eurostar which currently enjoys a monopoly on the track as sole rail passenger service operator, and from freight service operators.
Eurostar carried 9.2 million passengers through the tunnel in 2009. Eurotunnel says that there is still around 50 percent spare capacity.
"Today is a great historical event. We need and ask the support of infrastructure managers in all countries involved in this project. We are sure to need political support if we are to succeed in doing so," Deutsche Bahn's chief executive Ruediger Grube said in his presentation.
Both Germany and Britain threw their support behind Deutsche Bahn's plans, with UK Transport Secretary Theresa Villiers saying they were a very important step for international rail travel in Britain.
"The new services will give passengers greater choice and foster competition with Eurostar. They will help meet growing travel demand between our countries and connect two major financial centres, London and Frankfurt," Villiers said.
With congestion and security measures at airports extending the average London to Frankfurt flight duration of 1 hour and 40 minutes significantly, the German railway operator argues that passengers will view the alternative of going by train more favourably.
Deutsche Bahn expects that journeys to Cologne will take just under four hours with Frankfurt five hours away.
"I definitely like trains more than airplanes, but they are really turning trains into planes on rail," said Andrea Mubi, a 35-year-old Italian looking at the ICE 3 at the train station after getting off a Eurostar train from Paris. (Additional reporting by Jean-Michel Belot in Paris; Editing by Elaine Hardcastle and Greg Mahlich)