How much can one engine pull?

Seriously, they can pull all they can till they can’t,….if one isn’t enough, do as the real railroads do,……add engines 😀

Pat

Too many variables to give a suitable answer. I once had a Baldwin Model Locomotive Works New Haven EP-3 that would pull twenty mixed passenger/head end cars; with twenty-one it would struggle a bit and twenty-two would stall it. The layout was a completely level folded dogbone, with a sixty or so foot straight between the about forty-eight inch radius outer loops. I suspect that if the loops were larger, it would have pulled a few more cars.

It really does depend on the locomotive in question.  My large articulated steamers pull 50-60 cars with ease, some of the smaller locomotives struggle with 20 cars.

@PRRMP54 posted:

Too many variables to give a suitable answer. I once had a Baldwin Model Locomotive Works New Haven EP-3 that would pull twenty mixed passenger/head end cars; with twenty-one it would struggle a bit and twenty-two would stall it. The layout was a completely level folded dogbone, with a sixty or so foot straight between the about forty-eight inch radius outer loops. I suspect that if the loops were larger, it would have pulled a few more cars.

Dave, I still remember that locomotive running at the WB&A Tractioneers. That locomotive sure could pull. I seem to recall that the superstructure was a very heavy bronze casting. the drive was some sort of a chain.

It also depends on the track type and generation of rolling stock. Postwar flat-wheeled, modern fast-angle, MPC fast angle, and the all the k-line, MTH, Williams, Weaver, Atlas, etcetera. -- they all have widely  varied weights, frictions, and more...

my postwar 2333 magne-traction dual motored NYC F-3 will pull a 25~30+ car consist on gargraves with wide radius (over 42") turns like a champ - no sweat, but will struggle to start moving 5 or 6 madison heavyweights with smaller radius turns under 42"

@David Eisinger posted:

Dave, I still remember that locomotive running at the WB&A Tractioneers. That locomotive sure could pull. I seem to recall that the superstructure was a very heavy bronze casting. the drive was some sort of a chain.

You are correct. I have since acquired a couple more (all have different drives) to replace that one. And a couple of Alexander GG-1s; again with different drive systems. Five motors, four (maybe all five, I would have to extricate them to check) have different drives. I suspect that they were built by different owners.

We called this "the little engine that could". I used this MTH Railking loco from a Ready To Run set for our Town's Holiday Train show. It defied all odds as it pulled 22 freight cars and tanks up a steep grade (MTH graduated piers on Fasttrack) while nearly making a horseshoe turn of 036 curves before heading over a bridge! Combination of older Lionel billboard reefers and some newer MTH. Yes, I know that the cars are light but....! This ran for five weekends. It wasn't realistic but the kids (of all ages) loved it. Some of the more serious older gentleman would stop by and say "that won't work". I'd smile and start her up!

Mikki

@PRRMP54 posted:

You are correct. I have since acquired a couple more (all have different drives) to replace that one. And a couple of Alexander GG-1s; again with different drive systems. Five motors, four (maybe all five, I would have to extricate them to check) have different drives. I suspect that they were built by different owners.

...would like to see those...(hint, hint).

Mark in Oregon

This question gets asked so often and since the rolling qualities or our cars vary so widely it would be nice if we came up with a  standard way to test the tractive effort of our locomotives. I could imagine a pulley at the edge of a table with a test track inline with it and some sort of adjustable weight on the end of a string. This would be easy enough to set up that we could rate the pulling power of each of our locos and then we could  establish a way to derate the max tractive effort to determine a continuous pulling effort. Something like .75 max power for locos without traction tires and perhaps .50 max for locos with traction tires. I guess it would be asking too much for the manufactures to provide these pulling specifications. One thing I have noticed is the move to smaller motors in locos than those of 30 years ago. The first Alco PA's sold by Williams came with Mabuchi 545 motors. Today Mabuchi 385 motors seem to be the norm for most diesels. I would be perfectly fine with 385 motors if manufacturers would gear locos in a more appropriate ratio 15~20:1 would be about right for diesels and about 25:1 would be close for steam locos. This would all but eliminate the need for 545 motors in diesels or more than two 385 motors. Unless you like to cruise down the track at 250 scale mph like my brother.          j

@JohnActon posted:

This question gets asked so often and since the rolling qualities or our cars vary so widely it would be nice if we came up with a  standard way to test the tractive effort of our locomotives. I could imagine a pulley at the edge of a table with a test track inline with it and some sort of adjustable weight on the end of a string.

What about seeing how far a given loco could stretch a Bungie cord? You could compare to how many fishing weights it took stretch that same distance...or ACP45 slugs if you prefer....LOL

a force meter.

look up a digital force pull meter. lots of options, the trick is selecting one that measures low amounts of weight in small increments

@woodsyT posted

look up a digital force pull meter. lots of options, the trick is selecting one that measures low amounts of weight in small increments

I guess a Bungie cord is pretty low-tech, but I'm a kinda low-tech guy. Years ago, I found a major hot water leak in a school walking around barefoot. Easy-Peasy.

I then thought you could use a pulley arrangement with a known weight, say 5 pounds, on a $20 digital postage scale and see how many ounces/pounds a locomotive could lift off the scale. They are pretty accurate and cheap these days....

One of the YouTubers (can't remember who) that does reviews, gives the pulling force of different locomotives he tests.  For what it's worth.

The reason I said (for what it's worth) is that as stated earlier there are a lot of variables.  We all know are trains slow down on inclines and through curves, the reason cruise control was added to our locos.

There are plenty of 20N and 50N spring scales on Amazon among other places. One Newton is approximately 3.6 ounces.

Most O gauge locomotives have between 16 and 64 ounces (1-4 lbs) of drawbar pulling force.

@MainLine Steam posted:

The reason I said (for what it's worth) is that as stated earlier there are a lot of variables.  We all know are trains slow down on inclines and through curves, the reason cruise control was added to our locos.

Very true! And a huge variable is tires, or lack thereof. I have a RailKing SD60 with missing tires and it wont' pull a dead skunk off a rotted post compared to a GP-30 with tires.

As a side-barb, if anyone can tell me how to **easily** replace the tires on a RailKing vs about any other brand, I'd love to hear from you. It sounds great and puts on a good smoke show, but if I want to move more than a light string up a grade, I have to MU it with something else.

A forum search brought up a couple of related recent threads.
How heavy a train can you safely pull?
Measuring "Pulling Power"

@endless tracks posted:

What about seeing how far a given loco could stretch a Bungie cord? You could compare to how many fishing weights it took stretch that same distance...or ACP45 slugs if you prefer....LOL

That works for an individual but I was thinking we could standardize on one design. Finding bungie cords that have the same stretch profile would be difficult and the elasticity of rubber is quite temperature sensitive.  I was hoping we could standardize on one easy to duplicate unit of measure. Even something as simple as pennies in a small plastic container. Or a milk carton with a side cutout for adding or subtracting pennies. I have a triple beam balance and could count the number of pennies in an ounce. Such a rig would be cheap and easy for all of us to duplicate. So your measurements would be just as relevant at my house.  How many pennies before wheel slip. We could even use rolled pennies with 50 per roll then 50 loose pennies. Add rolls till wheel slip then take one roll out and use individual pennies till wheel slip for a finer measurement.      j

@JohnActon posted:

I was hoping we could standardize on one easy to duplicate unit of measure. Even something as simple as pennies in a small plastic container. Or a milk carton with a side cutout for adding or subtracting pennies. I have a triple beam balance and could count the number of pennies in an ounce. Such a rig would be cheap and easy for all of us to duplicate. So your measurements would be just as relevant at my house.  How many pennies before wheel slip. We could even use rolled pennies with 50 per roll then 50 loose pennies. Add rolls till wheel slip then take one roll out and use individual pennies till wheel slip for a finer measurement.      j

Even this wouldn't be a truly accurate measurement.  The coefficient of friction for the container against the specific track in use would vary a lot I suspect, especially if you didn't use the exact same container and brand of track.

I think a spring going to an accurate scale that is anchored in place would be a decent solution.  The spring allows you to gradually take up the tension and pulling power until the wheels stall or slip, the maximum reading on the scale is your pulling force for that locomotive.  The scale would be a type that holds the maximum reading until you reset it.

GRJ, too funny, but I was just reading your reply to this same question from back in 2021 when you posted your new reply just now. Seems the topic has been around awhile, with many different approaches.

One of my customers manufactured million-pound test rope for towing offshore oil rigs, and other things that cannot withstand a ridged connection, e.g. chain or cable. I did some hydraulic work on the test bed for them, which I recall being over 100 feet long. If I had a way to scale that, seems like I could start a new business! Too much math for me, though....LOL

Bob

I think 100 feet long is a bit too large for most layouts.

I have a scale similar to this one, the addition of a proper sized spring it all that's needed.

It is kinda cool that you would want to know how many cars an individual locomotive can pull but once you have done it I would not make a habit of it. Stress on the motor and drive gears might be trouble down the line. My personal experience is depending on the locomotive 45 to 50 cars is nice train.

https://www.amazon.com/Sci-Sup...Spring/dp/B0C6RDHQ7R

@gunrunnerjohn posted:

Even this wouldn't be a truly accurate measurement.  The coefficient of friction for the container against the specific track in use would vary a lot I suspect, especially if you didn't use the exact same container and brand of track.

I think a spring going to an accurate scale that is anchored in place would be a decent solution.  The spring allows you to gradually take up the tension and pulling power until the wheels stall or slip, the maximum reading on the scale is your pulling force for that locomotive.  The scale would be a type that holds the maximum reading until you reset it.

I was not thinking of the container resting on the track but a pulley mounted on the edge of the table and a cable connecting the loco to the container with the cable wrapping around the pulley and coming off at coupler height with the container hanging below the table top. The larger the diameter of the pulley the less force to turn it in order to minimize friction losses. The reason lab scales don't use springs is springs are not dependable they change with temp. and age. Spring scales could give relative values between different locos. Another factor in favor of the hanging weight is it could be used to assess the rolling characteristics of our rolling stock.   If the test track were on an adjustable incline it could tell you how much tractive effort is needed to pull a car or group of cars up your steepest grade.                                    j

@poconotrain posted:

It is kinda cool that you would want to know how many cars an individual locomotive can pull but once you have done it I would not make a habit of it. Stress on the motor and drive gears might be trouble down the line. My personal experience is depending on the locomotive 45 to 50 cars is nice train.

It really does depend on the specific locomotive you're pulling them with.  The weight, gear ratio, motor characteristics, and number of driving wheels all enter into the equation.  A large articulated locomotive with two gearboxes and a husky Pittman motor will pull a lot more than a non-articulated model, for instance.

@poconotrain posted:

It is kinda cool that you would want to know how many cars an individual locomotive can pull but once you have done it I would not make a habit of it. Stress on the motor and drive gears might be trouble down the line. My personal experience is depending on the locomotive 45 to 50 cars is nice train.

Not overloading a loco is the very reason I would want to know what the loco's max is so that I do not overload it.          j

You just have to try it for yourself.

The variables are:

• The locomotive, its motor(s) and its drive (China drive or drive shaft)
• The weight of the individual cars
• Curvature resistance
• Ascending or descending grade

If the locomotive feels too warm after 15-20 minutes of constant running, you need to reduce tonnage.  Some cars roll more freely than others.  My experience is that MTH trucks roll very freely and create less resistance.