I’m new here dose any one know how much weight can a single engine
Every section or division of a railroad has a hill or grade that is the steepest and is called the ruling grade. Every locomotive comes with a chart that gives the tonnage limit for different grades. That lets the railroad match the two. Different mdels are capable of different tonnage ratings.
The single engine can pull as much as its tractive effort says it can pull. Each engine type has different characteristics, from weight, weight on the driving wheels, to horsepower, and beyond. If the engine is small, but powerful, it will only pull as much as the point where its wheels start to slip. Keep the locomotive’s power the same, but make it twice as heavy on the driven wheels, and you will see it pull a lot more because it will have more traction.
So, your question is a lot like, “How sweet is an apple?” The answer is, it depends on the apple’s condition and make-up. If it is what most would call a pie apple, it won’t be very sweet. An Ambrosia apple is very sweet, while a Granny Smith is mostly a pie apple. For locomotives, a small docksider producing 300 horsepower won’t start a 2000 ton train in all likelihood. On the other hand, a single SD75 won’t have much of a problem, especially on level track. As Nick says above, add a grade to the mix and the drag behind the locomotive rises very quickly. Over 1% grade and you would definitely need two, probably even three of those SD75’s.
I feel I should add a correction to Nick’s post. The ruling grade is not always the steepest grade in a division. It is the steepest grade that a typical road engine for a typical timetabled train can handle by itself (without a helper). There may be a steeper grade in that division, but it will be a helper district, or the train will be assigned at least one other locomotive from the outset.
Crandell
Since you didn’t specify, note that there was and is a considerable size range in locomotives, even when looking only at standard gauge examples:
Steam:
The smallest is a tiny 0-4-0T, presently at Steamtown, that once belonged to the Dayton Typewriter corporation. It’s not much bigger than a Rav4.
The most drivers were found under the Triplexes, 24 (2-8-8-8-2 and 2-8-8-8-4.) The successful loco with the most drivers was the Virginian 2-10-10-2.
Diesel locos range from tiny 4-wheel ‘critters’ with 100HP (or less) engines to 6-axle, 6000HP behemoths.
Certain specialized locomotives, like the geared locos (Shay, Climax, Heisler) could outpull ordinary steam locos of comparable size - up to about 15MPH.
Two Panama Canal ‘Electric Mules’ can pull a 65,000 ton ship while climbing a staircase grade at about walking speed. Of course, they’re rack locos.
To get a meaningful answer to the question, you have to specify the locomotive. The general answer is, “As much as its tractive effort, horsepower and track conditions allow.”
Chuck
Here is some light reading on the suject:
Railroad Facts and Figures
Copyright AA Krug
Tractive Effort vs Horsepower
Many people confuse Horsepower (Hp) and Tractive Effort (TE). With this essay I hope to clear that confusion. I use some terms and formulas in this essay that may not be familiar. I suggest that you read the Definitions at the end of this document.
Assume a train that weighs 15,000 tons is stopped on a 1% grade. For every ton of train weight on a 1% grade a force of 20 pounds is acting to roll the train down the hill. A 15,000 ton train produces a force of 300,000 lbs. (15,000 tons x 20 lbs per ton = 300,000 lbs).
To prevent this train from rolling back down the hill we must apply an equal force in the opposite direction to the coupler of the first car. Imagine yourself holding onto the coupler of the first car and trying to hold the train from rolling back down the hill. It should be obvious that try as you might you will not be able to hold the train. No matter how hard you grasp the coupler you cannot hold the train because your shoes will simply slide across the ties and ballast. The adhesion of your shoes to the ties and ballast is not equal to 300,000 lbs. Thus not even if you were Superman could you develope 300,000 lbs of pull (traction) to hold the train.
The level of force required to break the adhesion of your shoes to the ties and thus slide your shoes is dependent upon two things.
- The coefficient of friction between your shoes and the ties.
- The w
Thank you Atlantic Central. I really enjoyed the clear explanation. I wonder if you could comment on DECELERATION, and particularly emergency stops. What are the issues you face in real life when you’re rolling along with so much inertia, and need to stop asap? Of course, you have loco brakes and freight car brakes with their combined adhesion, but do you also use the engines / traction motors to brake? Do couplers have a breaking threshold when they are pushed rather than pulled? Cheers, and thanks in advance.