Problem with Steam Powered Time Travel

The first person to try steam powered time travel did not think about the problem that the fire and steam would run out while he was gone. So the poor sotty bugger got left ahead in time.

That raises the question, that if you could choose to time travel, which way would you go? Forward or backward?

So the sotty bugger decided to invent the black box that ran forever, and so could be hooked up to the steam generator, and left to run so that the sotty fellow could return at will. But then someone stole the black box. And there are copies now. And they have a plan. But they don't have a clue.