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locomotive pulling tester

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  • Member since
    August 2015
  • 409 posts
Posted by Autonerd on Sunday, November 20, 2022 3:15 PM

Our club has a string that goes to a pulley in the ceiling, from which we hang various fishing weights. Our test track is on a 2% grade, and we have a chart that translates the that drawbar pull to a number "units" (for us, that's a 40' freight car) on flat, 0.8 and 2% grades (our ruling grades for Eastern and Western divisions).

By rating each locomotive, we can measure a train (using light posts in the yards placed 2.5 feet or 6 units apart), then use the pulling data to determine which locomotives will pull the train over what parts of the layout, and if and how much helper service we'll need.

We require each car to be right around NMRA weight. This way, we don't have to worry about varying car lengths -- we know the weight of a train based on its layout, and which locos will pull it.

Used to be that anyone ignoring this and trying to run the steepest section with inadequate power would be punhised with helper service from my Bachmann Penn Central GP40 of Shame, a locomotive with a geartrain that easily drowned out the most sophisticated sound system. Much to the delight of my fellow club members, I've misplaced that locomotive. Might have to replace it with something more obnixious...

Aaron

  • Member since
    January 2004
  • From: Canada, eh?
  • 13,375 posts
Posted by doctorwayne on Saturday, November 19, 2022 12:31 PM

I was curious about my locomotives pulling abilities and bought this small device from MicroMark...

You simply hook the wire to the coupler on the loco's tender, then while holding the pull-meter in place, apply power to the locomotive.

I seldom use it nowadays, as train make-up ranges from empty hoppers at an ounce (or less), and gondolas loaded with scrap metal, sometimes each close to a pound.
If the train can't make it up the hill, I simply add another locomotive, and, if necessary, another one as a pusher.

Wayne

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Saturday, November 19, 2022 12:16 PM

It's been covered before:

https://cs.trains.com/mrr/f/88/t/286791.aspx

I only brought out the scales because in another past thread someone asked specifically about either the BLI Baldwin Sharks or the Centipede. Basically it was a photo op. for the reply to the post.

Generally I don't measure drawbar pull, just run trains. Smile

Cheers, Ed

  • Member since
    November 2002
  • From: Colorado
  • 4,075 posts
Posted by fwright on Saturday, November 19, 2022 10:48 AM

Not trying to be negative, but I guess I have to ask the obvious question, "Why?"  The only thing a draw bar pull reading is good for is to compare locomotives, or compare the effect of adding weight.

The important thing to know is whether or not the locomotive in question can pull the train you want on your layout with the grades and curves you have.  Kind of a yes or no thing.  If it can't pull the train you want on your layout, there are a wide variety of actions to take - in part, the answers depend on whether the motor stalled (not enough torque) or the drive wheels are spinning and slipping.

the contrarian without a single drawbar pull measurementBig Smile

Fred W

....modeling foggy coastal Oregon in HO and HOn3, where it's always 1900....

  • Member since
    April 2021
  • From: saskabush
  • 127 posts
Posted by wvgca on Saturday, November 19, 2022 6:27 AM

a fishing weigh scale is often the easiest, and [most of the time] readily at hand ... choice of analog or digital ...depends on what you have handy ..

  • Member since
    May 2020
  • 1,057 posts
Posted by wrench567 on Friday, November 18, 2022 9:33 PM

  For my freight engines I use freight cars. For my passenger engines I use passenger cars. If they can't make the grade then I remove one car at a time or add another locomotive.

 I know it's not scientific but I'm not a scientist. But I do have an overabundance of locomotives.

     Pete.

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Friday, November 18, 2022 7:21 PM

thomas81z
question I have is what is everyone using  ???

Analog:

 DB_Baldwin2 by Edmund, on Flickr

Digital:

 Drawbar_pull3 by Edmund, on Flickr

While the digital model has more bells & whistles, the simple Ohaus spring scale does the job just as well.

Good Luck, Ed

  • Member since
    February 2012
  • From: CAPE CORAL FLA
  • 511 posts
locomotive pulling tester
Posted by thomas81z on Friday, November 18, 2022 7:08 PM

as the title says i remember people posting videos of a meter tied to the tender coupler or diesel coupler and seeing the " drawbar puller power, question I have is what is everyone using  ???

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