Drag freight can be any form of freight - the critical element is the train is loaded to the maximum (and some times a little more) tonnage that the locomotives can handle on a given terrirory.
In mountainous territory virtually all trains get loaded and powered to maximum tonnage for 'single' operation (without helpers). A 'drag' over the mountains when it gets to the flatlands will actually become a 'flyer' as it will now have much more power than is necessary to handle the grades that exist on the flatlands.
A 'drag' on the flatlands, will really drag. Back in the 'foggy mists of time' I was tasked with riding a empty auto parts train from New Castle, PA to Akron, OH - relatively speaking 'flatlands'. The power was a single 'brand new' SD-40. The MAXIMUM speed that was managed was 23 MPH (Maximum track speed is 60); when the ground elevates, the load meter Amps go higher and higher and speed goes lower and lower - approaching the minimum continuous speed (the speed at which the heat generated by the traction motor can be sustained indefinately - any slower the increasing traction motor heat will occasion observation of 'short time ratings' - exceed the time of those rating at the expense of a burned up traction motor.)
The ruling grade between New Castle and Willard (Akron is about the midpoint of the run) is Akron Hill - a 1% grade of a little over a mile in each direction as the railroad crosses the Cuyahoga River - with a 15 MPH speed restriction at the bottom of the grade. Minimum continuous speed for a SD-40 is 11 MPH. Long train have the benefit of the rear of the train descending the grade to shove the head end up the grade - short trains will have to handle the entire train being on the ascending side of the hill.
Never too old to have a happy childhood!
tree68I could be wrong, and I'm sure someone will come up with the origin of the term.
No origin, but I always read drag freights having only enough power to maintain a relatively steady and slow speed because the freight being hauled was not time-critical. More power, more speed mean higher costs.
The opposite of Don Prudhomme and Tom McEwan
Lithonia OperatorDoes the term refer to placing a priority on length/tonnage of trains, and not worrying about how long the train took to get to its destinations?
Even today, there are expedited trains (IM, mostly) and there are manifest trains (as well as unit trains). IM's run about as fast as is allowable (Amtrak notwithstanding). Everything else runs slower.
I could be wrong, and I'm sure someone will come up with the origin of the term.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Frequently I see the term “drag freight.” Or drag service or drag era.
It appears that this means a slow freight train. But why would a railroad intentionally run slow trains (if the track can handle fast ones)?
Why would a locomotive be designed “for drag service?”
Does the term refer to placing a priority on length/tonnage of trains, and not worrying about how long the train took to get to its destinations?
Still in training.
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