How do you measure pulling power?

I measure it by the maximum number of cars a loco will pull up my steepest grade, but I allow for wheel slip. This is probably very unprototypical, but I figure that, in N scale, wheel slip just grinds off any slick coating on the wheels, and harms neither loco nor rails. On the prototype, it probably ruins both wheels and rails.

I think we're more tolerant of wheel slip on diesels, mostly because it's harder to detect. I think that gives an advantage to our diesels, compared to our steam, where wheel slip is easy to detect.

I'll put up with a moderate-to-high amount of wheel slip in determining how much a loco will pull. How about you?

 

I would prefer only very moderate wheel slip, if any. The steepest part of my layout is on the helix, which is integral part of the main line. To test the engine I stop and try to restart the train.
Has anybody built a "pull-o-meter"? I thought about a special car, may be articulated, with a measuring device in it. But so far it is just an idea.

Christoph

 

Pete - I think pulling power is primarily an issue for those, like yourself, with grades on their layouts. My layout is perfectly flat, which means even my lightest locos (Atlas GP7's and RS-1's) have no problems pulling my 50 - 70 car trains.

 

Pull-o-meter?

Yeah, you could call it that.

Either that or a massive cerebral hemmorage!



This has been on the old Atlas forum a while back, basically a student-grade spring scale for like $8 with MT passenger car trucks stuck on it. You can measure resistance in a moving train, if your clearances are wide enough! Mine doesn't fit through the tunnel, but works everyplace else.

 

Nice rolling scale. Have you considered painting and decaling it for a prototype?

 

Well, this is exactly what I was thinking about. I missed the thread in the Atlas forum. Now I have to find such a spring scale somewhere headscratch:

I would have the problem whether to paint it PRR or Deutsche Bundesbahn. Or not at all.

Christoph

 

I measure min by the weight (in grams) of the cars that an engine can pull over the various ruling grades on my railroad. If an 9-44 can pull 200 grams up the 2.77% grade then that its rating for that grade. If it will pull 225 grams up the 2.68% grade then that is its rating for that grade.

 

Here's the scale I used. Student grade, but a lot better than measuring stuff in "MT boxcars".
http://www.auspexscientific.com/sprinscal50.html

 

Pete:

I measure by the number of cars that a loco can pull up the grade of the JJJ&E which is 2%, at the point where the wheels first start to slip.


If a loco can pull 17 cars up the grade at the point where the wheels slip, that load at that point is the maximum load for that loco.

You can measure it in grams,but knowing the exact weight isn't that important to me.

Stay cool and run steam.....

 

We have discussed this in another thread a few months ago when I complained about the way MR "tests" pulling power.

I think there are too many subjective factors that are built into each layout.

Bob has 2% grades. What about grades that are on turns? What wheels? Etc., Etc., Etc.,
What may be reported as 20 cars on your layout may be 5 on someone elses.

 

What I like about the scale is that 'real layout' conditions vary. I especially like to test it before and after I clean track, or wheels, or both, because the variability of so many issues is so hard to measue when you tinker.

This came up when I got the Atlas SD24 and it started to get slippery. Clean the track? Clean the wheels? Scuff the wheels? Add weight? And, all on a 2.5% grade and 15" curves? I could measure and test different situations and was able to solve it.

 

The only reliable measure of a loco's pulling power is the maximum tractive effort it can put out, similar to how prototypical loco's are measured.

For a scale, I'd suggest buying a trigger scale from a gunsmithing source, such as Brownells. You can buy scales to measure anywhere from an ounce to over 5 pounds reliably. They come in various flavors, and usually you can buy a scale for very low pulls (in ounces) or pulls from 6 ounces on up.

It's called mixing my hobbies!

Mark in Utah

 

Here's another view of the "Scale Test Car"



It's a hoot when it really stretches out to like 150 scale feet long.

The record 'pull' is 51 grams from my ABBA set of Kato F's at full slip. I can hoist an 30 car train up my 2.5% grade with 3 SD45's pulling about 25 grams (as shown in the above shot stalled on the grade)