There’s a new train pulling into the station in San Bernardino, a southern California city about 60 miles from Los Angeles. From the outside, it looks like any other commuter train, with three passenger carriages, blocky windows and a colourful blue exterior. But inside, it’s unlike anything the region – or the country – has seen before. The $20m Zero-Emission Multiple Unit, known as Zemu, uses a hybrid hydrogen fuel cell and battery system to propel the train and run other onboard electrical systems