# Speed matching



## Mister Bill (Jan 30, 2014)

Newbie question

I am running a BLI diesel in the lead and an Athearn (running backwards) as the trailer. The Athearn is slightly faster.

I have watched you tubes on speed matching, and it is almost over my head.

How big of a problem would it be just to let them run a little mismatched?

I have adjusted the acceleration rates to be about the same on both locos, so there are a lot of moving parts.

I have them mu'd at the moment, so both run under the number of the leader. 

Do you speed match before mu'ing while each retains their own number?

Bill


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## tullnd (Jan 3, 2018)

How are you doing the speed match?

I'm just starting to mess with a matched pair of units(two of the same model, same mfg, just different road numbers) and I'm using JMRI to speed match. It's a little tedious and honestly I don't have enough track to do it right for the higher speeds yet, but I'm just getting familiar with it all while I'm waiting on finalizing my layout.

From what I've read, using a computer program like JMRI seems to be a bit more accurate for scenarios where people are using different drive trains. It's really a matter of testing at the various speed steps and then adjusting until they match. Again, quite tedious, but I can see how it gets a lot faster after you do it over and over again. 

I'd be slightly worried to just ballpark it, cause while it may appear to work well at a few speeds you test, you may not notice if one is dragging or pushing at other speeds, and if you happen to run it on one of those for a while, it might put a lot of premature wear on the motor. I guess it depends on a lot of variables like the weight of that unit, the weight of the other unit in the consist, and all that as far as what damage it may or may not cause.


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## CTValleyRR (Jul 26, 2014)

First of all, your instinct is correct -- slightly mismatched speeds won't hurt anything, but you need to make sure that the speeds are close in ALL speed steps, because when you consist (mu) them, they will take commands together and both be in the same step.

Speed matching is pretty much a trial and error game. Do your best to match the speeds by programming each loco independently, then use your DCC system to consist them together with a separate consist number.


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## 89Suburban (Jan 4, 2017)

While we are on the topic I have 2 MTH diesels I am trying to speed match on my NCE Power Cab and apparently the middle speed CV is not adjustable. I just can't find a way for getting them to speed match.


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## jackpresley (Dec 19, 2017)

RailPro MU/Consisting

Seems almost too good to be true. I hope to eventually go to this. Skip ahead to 4:30 to see consisting.


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