How is Train Tonnage Measured?

Trains Magazine General Discussion
1

I was wondering how train tonnage was measured; is it by the total weight of all the cars, or some formula to determine the rolling resistance of each car? Any help is appreciated.

—Kasey K. KCK—

2

To the best of my knowledge it is the tonnage or total weight of everything. Rolling resistance is negligable in most cases with roller bearings. The exception is winter in the north where the lubricants get stiffer. I would suspect that once under way things would get back to normal pretty quickly unless the train stopped for a long enough period of time to cool thing down again. Every section of railroad has a ruling grade that determines how much tonnage can be pulled up that grade. That generally determines the number of engines or length of the train based on tonnage. Curvature can also create drag that would limit an engine but that is fairly rare in my understanding.

3

Thanks, I think that that’s all I’ll need.

—Kasey K. KCK—

4

The heaviest 4 axle cars now are 286,000 lbs. That works out to be 143 tons with the light weight of the car around 30 tons. That leaves 110 to 115 tons for the load. Aluminum cars used in coal train service weight between 20-25 tons when empty. That allows for another 10 tons of coal over what a steel coal car allows.

Soon the maximum will go to 305,000 lbs or more than 150 tons when loaded.