In light of the ongoing heatwaves spreading across Europe, Eurostar has amended its upcoming order for 50 double-decker trains to withstand temperatures up to 55C.The new ‘Celestia’ trains ordered last October were designed to function up to 45C.But following the series of heatwaves in France, the order has been changed.It comes after France recorded its hottest day since records began nearly 80 years ago, when temperatures peaked at 44.3C in the south-western town of Pissos.At least 48 people in France have drowned since the onset of the heatwave while trying to cool off, authorities said, and two young children were killed by heat in a car. A Eurostar spokesperson told the Daily Mail: ‘A decision has been taken to equip our new fleet of up to 50 Celestia trains with air conditioning capable of operating in temperatures up to 55 degrees. ‘These trains will enter service in 2031 and run into the 2060s so it’s essential to be prepared for the future.’ Eurostar Celestia, one of the new fleet of double-decker trains which will operate in the UK, is set to be able to cope with temperatures up to 55CGwendoline Casenave, Eurostar’s chief executive, told the Telegraph this justified the additional investment.She said this was because the trains are likely to remain in service for three decades – and by this time temperatures could be as high as in North Africa. Last year, Eurostar announced the €2 billion investment in up to 50 new double-decker trains built by Alstom Group – the first ever to operate through the Channel Tunnel and on the UK network. Eurostar confirmed an order for 30 trains, with an option for a further 20, marking a significant step in Eurostar’s growth journey to 30 million annual passengers.The 200-metre trains will be operable across all five countries served today, plus new destinations of Geneva and Frankfurt. Eurostar Celestia will have a bespoke design to capture the unique, premium experience Eurostar customers expect. The name of the fleet, selected by members of the Eurostar team, is derived from the Latin word caelestis, meaning ‘heavenly’. It comes after Europe, France in particular, were affected by heatwaves – with a pharmacy sign showing the temperature of 41 degrees Celsius in Bordeaux last monthSeat capacity is set to increase by 20 per cent on each new train. It is expected that each 200-metre set will have around 540 seats. If running in 400m formation (as through the Channel Tunnel today), there would be around 1,080 seats per service.Also in line with rising temperatures, Eurostar has continued to develop its ‘solstice plan’, an emergency response system during heatwaves.It involves monitoring air conditioning and water inside trains, as well as ensuring systems are in place for maintenance. It comes after trains were badly affected by the heatwaves last month.Eurostar said four trains between London St Pancras and Paris Gare du Nord were cancelled on a single day, 25 June, ‘due to expected adverse weather’ on the network.