# Walthers Mainline runs sloooooooooooooooow



## Stejones82 (Dec 22, 2020)

Not sure to post here or HO. 

My first loco was a rather inexpensive, but new, Walthers Mainline SW1. Ran great on DC! Good low speed, and fast around the track. 

Friday, I hooked up the DT Zephyr and I used this loco to try as DC on DCC as per Quick Start Guide. It worked, but the top end speed had fallen way down. Guesstimate: about half. I figured, "Well, maybe that's what you should expect running DC on DCC. What do I know?" 

I put in a Digitrax Decoder yesterday and it still runs very slow. Nowhere near what is was on straight DC. I put a DT decoder into my Bowser DS4-4-1000 also. It runs, a little slower, but the speed degradation is nothing like the Walthers. 

Now, it is a switcher so slow speed control is more important. I have not yet checked the CVs, should be the default ones. I'll make up a program track after church today so I can reassign addresses and check CVs. Maybe that's all it is. 

Anyone else experience a loss of speed changing over from DC to DCC?


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## D&J Railroad (Oct 4, 2013)

I think F7 is the switcher control on some of the decoders. You didn't mention which decoder you installed.
The switcher mode will make your loco run much slower for switching operations.
You might also consider going into the options of your command station and turning off the DC mode. That will skew what I call the sine wave which will mess up operations of the DCC functions.


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## Stejones82 (Dec 22, 2020)

Installed the DH126PS decoder - 2 function.


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## DavefromMD (Jul 25, 2013)

I experienced the same thing with a Walters Trainline F40PH after installing a digitrax DH126 decoder. Top scale speed on DC was about 90, on DCC about 55. It may have to do with DC power pack being 15-16 VDC while my NCE Powercab operates at 12V.

Switching speed was off and max voltage CV setting was at 255, midpoint at 150.


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## D&J Railroad (Oct 4, 2013)

Yes, that decoder has switching speed function. Read the instruction sheet.


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## CTValleyRR (Jul 26, 2014)

A lot of things can cause a loco to run slower in DCC, especially if there are sound features sucking up power as well. You will want to tweak the performance of every loco you install. Boost starting voltageuntil the loco just crawls in speed step 1. Tweak the max voltage so that the top speed is where you want it (personally, I'm running a railroad, not slot cars, so I don't want my machines ripping around at a scale 90 mph). Momentum set too high can also make a loco take forever to reach its max speed setting, so I turn that off until I have the speeds where I want them.


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## Stejones82 (Dec 22, 2020)

CTValleyRR said:


> .... You will want to tweak the performance of every loco you install. Boost starting voltageuntil the loco just crawls in speed step 1. Tweak the max voltage so that the top speed is where you want it ...


So much to learn, but seems fairly intuitive? 

I will set up the program track this afternoon and begin learning CVs and such. 

But perhaps you might explain further about "tweaking" voltages? Is that something to do to the decoder itself? Or via the controller?


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## CTValleyRR (Jul 26, 2014)

It is done by programming CVs. Look in the decoder's instructions, you'll find CV's for min voltage (sometimes starting voltage), mid voltage, and max voltage, and momentum. These take a value from 0 to 255. Unfortunately, trial and error is the only way to dial it in. I usually start by changing the value 20 at a time, then gradually narrow it from there. Making a note of what you set it to helps, and it's a good idea to keep a written record of your final settings as well.


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## MichaelE (Mar 7, 2018)

Slow is better for trains. It's not the Indy 500. When is the last time you saw a freight train going 90 MPH?


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## DavefromMD (Jul 25, 2013)

MichaelE said:


> When is the last time you saw a freight train going 90 MPH?


Not a freight train but here in the NE corridor, Amtrak trains routinely go those speeds.


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## MichaelE (Mar 7, 2018)

Scale speed of 90 mph hardly looks good on 18", 22" or even 24" curves though.


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## CTValleyRR (Jul 26, 2014)

I agree with Michael: speed is like water -- it doesn't scale properly. Even if the prototype goes that fast, 90 scale mph in HO scale looks too fast to me given the size of your layouts (even 20 miles in HO is almost 405 yards).


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## Stejones82 (Dec 22, 2020)

I was not trying to argue for or against the idea of a freight train running fast. I merely was worried that perhaps the locomotive was not performing as it is engineered to do so. That there may have been something wrong either with the locomotive, the Decoder, Or worse, something I had done wrong.

Personally, I like the Site of trains moving slowly.


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## mesenteria (Oct 29, 2015)

The decoder takes some of the voltage, the drive mechanism's internal resistances take some, and the resistances of the trailing or leading rolling stock take their share. The rest has to be metered out by the decoder to the drive mechanism until the available voltage has all been dialed in, knob fully rotated. So, newly decodered models virtually never get to the previous DC speeds...they simply can't. If the factory defaults for the decoder already has the full ranges for mid-speed table voltage and maximum speed voltage (CV's 6 and 5 respectively), then there's no assigned value for CV2 (V-Start) that can possibly make a difference. It just means that more voltage will be assigned when you get CV2 properly set, and you'll have that much less at the top end since you're already well down the so-called voltage path.


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## D&J Railroad (Oct 4, 2013)

MichaelE said:


> Scale speed of 90 mph hardly looks good on 18", 22" or even 24" curves though.


but the kids love it when they get to play with it with no supervision.


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## CTValleyRR (Jul 26, 2014)

D&J Railroad said:


> but the kids love it when they get to play with it with no supervision.


No such animal in my house.


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## CTValleyRR (Jul 26, 2014)

Stejones82 said:


> I was not trying to argue for or against the idea of a freight train running fast. I merely was worried that perhaps the locomotive was not performing as it is engineered to do so. That there may have been something wrong either with the locomotive, the Decoder, Or worse, something I had done wrong.
> 
> Personally, I like the Site of trains moving slowly.


No, you weren't, DavefmMD was.


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## Signman Mark (Jun 13, 2021)

MichaelE said:


> Slow is better for trains. It's not the Indy 500. When is the last time you saw a freight train going 90 MPH?


What is your power, loco, and decoder setup on that slow-running loco? That's fantastic and is the sort of creeping speeds I'm looking for! Thanks.


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