High-speed double-decker trains to run through Channel Tunnel for the first time

Computer-generated picture of Eurostar Celestia train arriving in London St Pancras

Train company Eurostar has said it plans to run double-decker trains through the Channel Tunnel for the first time.

The double-decker trains are expected to operate from May 2031, with each one able to carry 1,000 passengers.

Eurostar has so far ordered 30 of the trains but could purchase up to 50 in total.

The company that will make the trains, Alstom, currently produces the only high-speed double-decker train in the world.

The fully electric trains, named Eurostar Celestia, will be the first major fleet of double-decker trains on UK railways and the first high-speed double-deckers to ever run in the UK.

What will Eurostar's double-decker trains be like?

Double-decker trains need to include interior stairs which take up extra room

The fully electric fleet of trains will be named Eurostar Celestia, which comes from the Latin word caelestis, meaning "heavenly".

The colour of the train has not yet been decided, but the current colour of Eurostar trains is grey, dark blue and yellow.

Each train would be 200m long. Double-decker trains don't have twice as many seats as a single-deckers though, just because there needs to be room for interior steps, but there would be a fifth more seats.

This means an increase from just under 900 seats on the current service to just over a thousand.

Eurostar chief executive Gwendoline Cazenave told the PA news agency passengers will enjoy a "special experience", with more legroom and extra areas for bikes and wheelchair users.

She added that there will also be "surprise spaces", but did not say what these would be.

How will double-decker trains fit through the tunnel?

Le Shuttle, which carries vehicles and passengers through the Channel Tunnel, has two decks

Katy Austin, BBC transport correspondent, told Newsround:

"The new double-deckers won't be much higher than the old ones, just 16cm taller. So a height problem seems unlikely."

The high-speed line between St Pancras and the Channel Tunnel was built to European standards, which means higher trains can fit through.

While there are currently no double-decker passenger trains going through the tunnel, Le Shuttle, a vehicle-carrying train service, has a single deck for things like buses and trucks and a double deck for cars and motorcycles.

Are there double-decker trains in the UK?

Britain's only double decker train was Bulleid's 4DD

The trains will be the first major fleet on UK railways.

A limited trial of two double-decker trains for services in London between Dartford and Charing Cross took place in the 1950s and 1960s.

They were stopped in 1971 because they were considered too cramped and expensive to run.

Most of the UK's rail network is not considered suitable for double-decker trains because of the height of many tunnels and bridges.

And if you're wondering whether this will mean double-decker trains will be coming to the UK, Katy Austin says probably not.

"These trains are for use on a specific route between London and the Channel Tunnel, ending up in European countries where double-deckers are already used.

"It would likely be too expensive to make changes across the UK's railway network to accommodate them more widely," the transport correspondent told Newsround.

So if you travel on a double-decker in the UK, it's more likely to be a bus.

What other countries have double-decker trains?

Double-decker trains like this one in Bavaria, Germany are common across Europe

Although there aren't any in the UK, double-decker trains are very common across Europe.

France, Germany, Italy, Switzerland, Netherlands, and Spain are just some of the countries that have them.

India and USA also run double-decker trains across some of their routes.

Alstom's Avelia Horizon is the only high-speed double-decker train in the world and it currently operates in France and Morocco.

What other special features are included on European trains?

There are trains with special play areas across Europe including this one in Ukraine

While Eurostar hasn't given exact details of how the inside of the train will differ, some of the special features in trains across the world could give a clue.

One of Newsround's favourite additions, which can be found on trains in France, Finland, Switzerland and Sweden, is a child-friendly carriage.

Switzerland and Finland, for example, both have train services which come kitted out with their own play area, complete with a slide.

Last year the United Nations Children's Fund (UNICEF) teamed up with the Ukrainian state railway company to launch Ukraine's first children's carriage.

Elsewhere, Japan also has some trains with play areas, including one which has a ball pit.