When I worked for the Fort Worth & Western running X-SP 2248, we were heading south from the Ft Worth Stockyards to 8th Ave Yard following a freight train. There is a short (less than 2 mile) stretch of 2% up into 8th ave and the freight stalled on the hill. We locked knuckles with the rear of the freight, kept our 6 passenger cars on our drawbar, and our 106 year old 10 Wheeler gave them a mighty shove up the hill.
I wish I had a recording of it. It was awesome.
I caught hell from the president of the company for doing it too. He told me 2248 was NEVER to be used moving freight cars again.