Model Railroading > That will put the Engineer Back in His Seat....

My late era SP mixed freight with a EMD Demo/Leaser SD70M, SP SD40T-2 and AC4400 coming down the grade at Cabarton on the Caldwell Model RR Club layout. Toward the end of the train you see a phenomenon that also happens with prototype trains, but not quite as exaggerated as here. Cabarton (station in distance) is a flat area in a long downgrade. As the rear of the train settles into this flat spot, rolling resistance pulls the slack out of the train that was compressed against the locomotives and their dynamic brakes. But as the cars resume the downhill journey there comes a point where the remaining cars on the flat can no longer resist the pull of the cars on the downgrade, and all the slack runs back into the locomotives that are in dynamic braking. So you see the sudden rush forward followed by the almost stopped like appearance as the slack rebounds off the locomotives for a brief moment.

Ted Curphey
Ontario, OR

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Exactly what happens at "drawbar flats" on the old South main of Cajon Pass between Summit and Cajon.
JB

Back in the days of the caboose there would be some old head conductors giving some A** chewing to the head end about train handling skills!! Some would be more tactful than others who would come right out and say what they thought. Makes my ears burn just thinking about some of those crusty old buggers.