The engine was one of the old locomotives of the 'Highland Light' class of around 1870 which Bond had heard called the handsomest steam locomotives ever built.
Energy to drive a steam locomotive can be stored in other materials besides water for example, a team at Tohoku University in Japan has studied materials that can store large amounts of heat when heated.
To my ears the torch hissed louder than a steam locomotive, and when he used it to cut through steel, it blew off thousands of tiny pieces of molten metal that swarmed around him like angry fireflies.