how would i go about figuring out how many cars my steam locomotives can pull if they were real life locos? i’ve found a website that has information about locomotives that look like my models and are built by the same companys. it gives info such as tractive effort, weight on drivers, cyclinder diameters, and such. i think knowing the number of cars my models can pull based on the prototype would add to the realism of my next railroad. and i know there are variables like grade, types of cars in the consist, and such. thanks for the help.
Most railroads rated steamers for certain freight tonnages over certain divisions of their railroad. Passenger ratings were entirely different. It was all really quite complicated. One example was that N&W rated the Class As Westbound from Norfolk and Eastbound from Roanoke for far more than they could lift over Blue Ridge, but since there were always Class Y pushers available on the hill they didn’t worry much about whether the train stalled or not, on Blue Ridge. I have never been able to determine for certain whether they used a lesser ruling grade or a speed rated number on that section. Best thing to do is do some historical research on whatever road you model.
Virginian is right about checking out your prototype: the proper historical society may have copies of employee timetables which list tonnage ratings for specific locomotives. However, what the prototype could pull usually doesn’t have much bearing on what your model of that prototype will pull. Because mass doesn’t scale down like dimensions and because the ratio of friction to power in a mechanism is different in a model than in full-size, your locomotive probably won’t handle as many cars as its prototype. Even more rolling resistance is created by our relatively small radius curves, our too-steep grades, and our abrupt turnouts. Still, it is interesting information to learn, and you might also find it interesting to learn how to improve your locos pulling power. Good luck in your search.
Wayne
Jason,
you got a very accurate answer from Wayne. But there is one possibility he forgot but I am using: -I model 1 to 87 (H0scale) and I don’t accept any compromise in curve radii. That means my smallest curve is even larger than the smallest on prototypes (scaled down of course): 80 inches (160 inches diameter). On the one side this looks awfully but - also for me - more important is that I do not need any extra weights in the cars! In addition I use metal wheels for smoother rolling of cars. I have only brass models of large steamers which mostly require large curves for themselves and do not have any traction tires, but none of these has any problem to haul 130+ cars on level track - as it was reality! If you have enough room and love prototypically long trains I would heavily recommend to use only large curves and therefore to omit extra weights in cars. My experience with this method is that the “tonnage” ratings for the engines are easy to recreate or even to surpass - and usually the mass produced plastic model locomotives have mor pulling power than the more accurate brass ones.
Good luck!
Johannes
Remember a steam locomotives tractive force decreased as the weather got colder,that is below 32 degrees. The site www.steamlocomotive.com has a calculator that will tell the tractive force under different conditions,like driver diameter and boiler pressure.