Pulling Power of Locomotives

I didn't see any real "answer" about the pulling power of O-scale model locomotives, that is the thread title.

I will say, short of the obvious issue of insufficient lubrication, it's pretty rare to see metal gears stripped in our models.  There are issues with gears sliding on shafts, gears splitting because they were press fit onto too large a shaft, etc.  Plastic gears, OTOH, have been indited in a number of gear failure examples.

Worm gears are especially susceptible to a lack of lubrication as they experience multiples of stress when compared to two mating spur gears, so if you're going to see a failure of a metal gear, the worm gear is frequently the one that you'll see.  Also, the worm gear is usually bronze and the worm is steel, so the worm gear is going to take the brunt of the wear.

Seems pretty simple.  Put as many cars as you like behind the engine and if it don't go, start taking them off until the engine seem happy with the load.  Even identical engines sometimes do not preform identically.

This ain’t a question that can have a one size fits all answer,……everyone’s layout is different…..Bill hit the nail on the head, pile them on and take off what don’t work,….these manufacturers ain’t figuring on gear strain, gear wear, etc, etc, they’re mass produced toys, …….John pointed out the obvious potential pitfalls, but the big factor also is longevity, just because a model train can pull a certain load now, doesn’t mean it will with serious continued use…..a man’s got to know his limitations,…..

Pat

There was a thread a long time ago where some garage measurements were made with a pulley and weights so the results were in pounds of force. Where we seemed to be headed in the die cast thread is "what weight of cars can I pull (assuming modern cars with low rolling resistance) and at what speed without wearing or taxing my engine?". Yes, there are lots of variables. But what if I did have the means to try to pull 20 or 30 die cast hoppers? It would look awesome but would my motor overheat or would I start to wear the worm gear(s). I don't think that question has an easy answer but with the right data and knowledge of gear loading and lubrication you could calculate it. But I think you answered part of your own question Jim, it's reasonably easy to determine pulling power with a weight (or fish scale maybe) but HARD to determine the safe pulling power limit that doesn't wear out your engine. I have engines with over 2000 hours that show no obvious signs of wear. I would hate to damage a $700 steam engine by overloading it.

@harmonyards posted:

This ain’t a question that can have a one size fits all answer,……everyone’s layout is different…..Bill hit the nail on the head, pile them on and take off what don’t work,….these manufacturers ain’t figuring on gear strain, gear wear, etc, etc, they’re mass produced toys, …….John pointed out the obvious potential pitfalls, but the big factor also is longevity, just because a model train can pull a certain load now, doesn’t mean it will with serious continued use…..a man’s got to know his limitations,…..

Pat

Post of the day! When I had a layout, it was flat, i.e. no grades. I enjoyed having the steam locomotives pull at least 40 cars. I had a C&O hopper train of over 60 cars, and one C&O H8 handled it with no problems. Any train that a single steam locomotive wouldn't pull, simply had some cares removed. In my opinion, any steam locomotive model that has added weight, i.e. way too heavy, will over stress the model's drive train. Thus, I never added any weight to the locomotives, steam or diesel. However, many freight cars had weight added plus smooth rolling trucks.

@Bill DeBrooke posted:

Seems pretty simple.  Put as many cars as you like behind the engine and if it don't go, start taking them off until the engine seem happy with the load.  Even identical engines sometimes do not preform identically.

I like and agree with all of the responses, however with that being said, IMO Bill summarized it best!

Real world testing beats all the calculations in the world.

Point I want to make is when designing any product, calculations are done to be sure it has a reasonable chance of working correctly.  Once the design is complete, any competent manufacturer of "mass produced products" builds prototype(s) to see how well it actually works.  Testing is conducted, and the effects on the prototype is evaluated.  Once the "bugs" are sorted out, a test run of production units is produced and further tested.  Then once OK production for consumers is started.  You may have a tendency to think on lower price items this would not be the case, but still applies if you want to stay in business for the long run.

Even an established Manufacturer can put them self out of business, if they get a reputation for producing junk.