By the end of the 19th century, the standard goods locomotive in Britain had been based upon the tried and trusted six-wheel tender engine design - if trains needed more power the railways’ operators simply added a second locomotive. By the start of the 20th century, heavy freight steam locomotives were starting to look rather big and powerful, if not always successful. As greater power was needed, so things started to get a lot more interesting, with eight- and ten-coupled freight locomotives starting to emerge, culminating in British Rail’s ‘9F’ 2-10-0, the last of which was built in 1960. These were among the biggest and most powerful steam locomotives to be built in this country. This is the story of the evolution of the British heavy freight steam locomotive from humble beginnings to massive freight haulers.