They say torque and traction wins but it seems the diesel has the advantage in both categories!
http://www.youtube.com/watch?v=T-D1KVIuvjA
http://www.youtube.com/watch?v=T-D1KVIuvjA
Steam verses diesel
- Thread starter bwells
- Start date
I goofed up big time, try this one: No way did Chuck do that!
[FONT="]http://www.youtube.com/watch_popup?v=FLQhvruimfs[/FONT]
[FONT="]http://www.youtube.com/watch_popup?v=FLQhvruimfs[/FONT]
Selector
Well-Known Member
It's all about adhesion and hp. HP = Tractive effort X Speed. You don't get tractive effort without adhesion, and you don't get adhesion without friction. Friction comes via force. Force comes from gravity in this instance. Gravity works on mass. The more mass, the more gravity has an impact.
Except in the cases of truckless steamers, their weight is shared between axles that are driven or unpowered. No power, no tractive effort. So, if there is even one axle outboard of the coupled or geared axles, some of the steamer's weight doesn't contribute to the tractive effort component of adhesion. Diesels are almost always different, although sometimes an inboard axle in a three-set truck is without a traction motor. Usually, though, all the diesel's weight is contributing to adhesion for the traction axles.
As a general rule, a diesel can start a train it can't pull when at maximum tonnage, and a steamer can pull a train it can't start. Steamers generate more HP as they generate speed, whereas diesels fall off much more rapidly on their HP curves as speed rises.
Remember that most Northern Class steamers can generate as much, or more, HP than modern diesels after 40 MPH. In fact, no diesel matched the most potent steamers until the 70's, and in that case they had to make a twinned diesel such as the DD40X or whatever it was that the UP crafted. The Allegheny 2-6-6-6 and the Niagara 4-8-4, as notable examples, generated in excess of 6000 HP, and the Penny's Q2 generated about 7000 HP. Some claim that the Allegheny also exceeded 7000 HP.
In this video, the steam tractor would outweigh the motored tractor by almost two-to-one. It would have lower equivalent gearing, and larger diameter 'tires', too, so it would have massive tractive effort.
Except in the cases of truckless steamers, their weight is shared between axles that are driven or unpowered. No power, no tractive effort. So, if there is even one axle outboard of the coupled or geared axles, some of the steamer's weight doesn't contribute to the tractive effort component of adhesion. Diesels are almost always different, although sometimes an inboard axle in a three-set truck is without a traction motor. Usually, though, all the diesel's weight is contributing to adhesion for the traction axles.
As a general rule, a diesel can start a train it can't pull when at maximum tonnage, and a steamer can pull a train it can't start. Steamers generate more HP as they generate speed, whereas diesels fall off much more rapidly on their HP curves as speed rises.
Remember that most Northern Class steamers can generate as much, or more, HP than modern diesels after 40 MPH. In fact, no diesel matched the most potent steamers until the 70's, and in that case they had to make a twinned diesel such as the DD40X or whatever it was that the UP crafted. The Allegheny 2-6-6-6 and the Niagara 4-8-4, as notable examples, generated in excess of 6000 HP, and the Penny's Q2 generated about 7000 HP. Some claim that the Allegheny also exceeded 7000 HP.
In this video, the steam tractor would outweigh the motored tractor by almost two-to-one. It would have lower equivalent gearing, and larger diameter 'tires', too, so it would have massive tractive effort.
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