It seems like when I see a picture of a steam engine pulling a small passenger train there is a diesel cut in to help it. Why is that? Is it for power are some other reason?
Rail pictures.net picture
Lee
Just in case.
Sometimes it is done to comply with insurance requirements, though that is not case with 844, the diesel is used to assist the train to track speed and provide dynamic brake capabilities it also can lend a hand when required and provides a measure of protection in case of steam failure.
Dave
I have heard of UP 844 being the helper on Archer Hill. A diesel failed on a freight train, and 844 and a short consist were behind, getting caught in the jam. After the “you can’t do that with a steam engine” and “how do you think we got trains up the hill 50 years ago?” conversations were had, they coupled up and shoved the train over the hill.