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Thread: Speed matching change with load

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    Default Speed matching change with load

    I'm at the point of beginning to speed match my road engines. Once done, they should play together fairly well. My question is this: will the matched speeds change significantly when a load is added? In other words, will my carefully matched mu'd engines still be relatively matched whilst pulling 10 cars as well as 40 cars, or is this a non-issue?

    Thanks for y'all's responses!

    G & LE RR

    west end full opt.jpg

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    I can't help you with your speed matching question but the backdrop on your layout is absolutely fab
    Thanks, Tom

    Expect nothing except the opposite of what you expect, and then expect it to be something other than that ! Then that's about what it will be

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    Quote Originally Posted by iwlf View Post
    My question is this: will the matched speeds change significantly when a load is added? In other words, will my carefully matched mu'd engines still be relatively matched whilst pulling 10 cars as well as 40 cars, or is this a non-issue?
    Shouldn't be an issue. At least, I've never noticed it as an issue.

    And yeah, what Tom said. Great backdrop.

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    I agree with what OTFan said.
    They should run together just fine with or without pulling a load.
    The Little Rock Line blog


    “Never argue with an idiot. They will only bring you down to their level and beat you with experience." George Carlin

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    I do this every time I run a unit train through the flood loader; I have to increase the throttle to keep the two-loco consist moving as the cars get loaded down. No issues. Speed matching has to be a lot more precise with no load than with load, so when you set up the tables get the locos to match with no cars and you'll be good.

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    Thanks for the responses. I was hoping that was the case, making life easier. The backdrop was painted by an art teacher friend and I agree, she did an "over-the-top" job, although she wants to come back and add some "detail".

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    I'm going to give a slightly more complex answer.

    On the one hand, speed matching matters a bit less as the load increases. If the two engines are off, one might do 60% of the pull, one might do 40% if they are not matched well, but they will both pull. This also means that for many uses super-precise speed matching is not so important, close enough works out ok.

    On the other hand, if you're trying to run long trains, or trains on a significant grade there can be an issue. If one is doing 60%, one is doing 40%, the 60% will slip first and the whole train will stall out as it's trying to do too much for the traction it gets from the rails. Here having a 50/50 match is beneficial.......

    But that's a 50/50 match under load. If you're going to speed match them, say using a marked distance to time, do it while they both pull an identical load, e.g. about half the train you want to run. Matching under load will get you maximum pulling power/train length. They may not though be matched at idle.

    Thus it kinda depends on your situation. Just want to run two engines together on a door layout with short trains? Get them semi-close and call it good enough. Want to pull 50 cars up a 1.5% grade on a large club layout? Better match them under load as close as you can!
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    Leo Bicknell

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    Uh.....if your locos are 20% or more off in speeds, then you NEED to go back and re-speed match them, period.

    I agree they should be close, and there is no reason that one can't get them that close.
    As long as you can get them close, then the weight of the train will only help even them out. Even then, the only time you'll notice that they might be unmatched is when you start the train rolling, the longer the train, the more weight you have and the more it'll even them out.

    The only time that I can see that they need to be spot on is if you are running a train with loco's on both ends: DPU's (Distributed Power Units).
    The Little Rock Line blog


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    The difference in speed is not the same as the difference in pull under load. A 5% speed difference can yield a 60/40 work split.
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    Leo Bicknell

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    I have 3 Atlas GP 38-2 locos. I usually run the 2 closest matched locos together with the faster one in dpu. It's to help keep the slinky effect out of the MTL couplers I use. As long as I keep the speed down, I don't usually have any problems with string lining. I run 60' cars max and try to keep them a little heavier.
    A simple man trying to run my trains...

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    I am going to toss out another method, that I use. Not necessarily the best, but works well for me. To start, let me say that I have a Unitrak oval of, I think 28" that I use for testing/break in, as well as programming track. I use ESU LokProgrammer and also JMRI. I actually like the JMRI for "fine tuning" motor and sound.

    I use the 3 cv's, (2,5,&6) along with a speedometer. I also use an Aztec roller track cleaner behind each and every loco that I am programming. No bid deal, same car, same roller, same weight and it sure keeps the rails polished while programming. I can get each loco running exactly the same ( + or - ? ? ?). Also, I turn off all acceleration and deceleration while speed matching. Later I go back and assign some momentum to some locos and never do on others.

    I just found out, with a lot of help from many DCC pro's that there is quite a difference between ESU Loksound v4 decoders and ESU v5 decoders. If getting ready to purchase v5 decoders make sure, if you want the 3 cv capability, that you purchase ESU Loksound v5 Micro DCC. There are severe differences in setting momentum as well.

    I am posting a thread, short 2 minute, video under "Steam" that shows the speed matching of my KATO 4-8-4 and my recently completed Key 4-6-6-4.

    Stay well,
    Carl
    Carl Sowell - El Paso, Texas
    Southern New Mexico N Scalers
    Jackalope & Western RR
    Las Cruces, New Mexico


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