In the days before my career in photography I operated heavy equipment. Seeing that that was more than forty years ago, some of the older machines required a small gasoline engine to start the big diesel. The little guy was known as a ‘pony engine’. You’d start the pony engine and as it ran it cranked the diesel, warmed it up, and after a few minutes diesel fuel was injected and the big guy would fire. Most likely more minutiae than anyone really needs, but seeing this at a local steam tractor reunion brought back memories.