This article is more than 3 years old Reducing HS2 train speed would cut emissions and noise, report finds This article is more than 3 years old A small reduction in the top speed of trains on the planned high-speed line from London to Birmingham would increase journey time but massively reduce carbon emissions and noise, independent analysts tell -- * Share via Email Anti-HS2 signage around Buckinghamshire. The 117-mile line will cut through the Chilterns. [ ] Anti-HS2 signage around Buckinghamshire. The 117-mile line will cut through the Chilterns. Photograph: Felix Clay/The Guardian A small reduction in the top speed of trains on the planned high-speed line between London and Birmingham would increase journey times by just 4.5 minutes, but would massively reduce carbon emissions and noise, -- scheme. Research commissioned by objectors to the 117-mile HS2 line through the Chilterns shows that if trains were limited to 300 kilometres an hour rather than the proposed 360km/h, they could save hundreds of thousands -- levels by up to 30% from up to 18 trains an hour, they say. “The 23% energy saving achieved by reducing the maximum HS2 speed to 300km/h would translate to an equivalent saving in carbon emissions. HS2 Ltd’s own projections indicate that the HS2 scheme will give rise to a net carbon emission of 2.1 to 2.6m tonnes carbon dioxide equivalent over a 60-year period,” says the report by SLR Consulting and a team of experts, commissioned by the HS2 Action Alliance (HS2AA). The total emissions could be as high as 6.5m tonnes due to -- committee on Monday. No other country runs high-speed trains at more than 300km/h, which is now the accepted norm in China, France, Germany and Japan, the report said. -- significant advantages,” the report states. HS2 Ltd has made its economic case to government by claiming that the high-speed line will lead to a significant decrease in air, car and freight travel. But the consultants, who are independent of the communities objecting, argue that their assumptions are wrong and that -- “We believe these assumptions currently overstate the magnitude of modal shift [in transport] that will be achieved. The assumptions of HS2 are very unclear,” they say. Acoustic experts added that trains running at more than 300km/h make -- acoustic report. A spokesman for HS2AA said: “In 2013, transport secretary Patrick McLoughlin said cutting minutes off the journey time between London and Birmingham was ‘almost irrelevant’, saying that the route was essential -- * Greenhouse gas emissions * HS2 * Climate change * Rail transport -- [p?c1=2&c2=6035250&cv=2.0&cj=1&comscorekw=Travel+and+transport%2CGreenh ouse+gas+emissions%2CHS2%2CEnvironment%2CClimate+change%2CRail+transpor t%2CTransport%2CUK+news]