Speed matching dissimilar engines? Genesis with Bowser?

Model Railroader Electronics and DCC
1

I’m new to trying to speed match diesels in dcc, using just the 28 speed steps, on an NCE Powercab system:

My son has two of the Genesis SD90MAC-H engines, and I will have a larger fleet of Bowser SD40-2’s once they are all here (most -2’s on hand are plain dc right now but some do have dcc/sound). We now have some longer freight trains that will actually require two diesels to work together, so it makes sense to speed match the Genesis (Tsunami) units with the Bowser (Loksound 5) units.

To complicate matters, Athearn does NOT state dcc default settings in the manual, because it is written for more than one engine. The Bowser settings for Loksound 5 are CV2 (min voltage)=1, CV3 (acceleration time)=20, CV4 (deceleration time)=20, CV5 max voltage = 255, CV6 (medium voltage) = 88.

The Bowser units run extremely well at slow speed, run slower at most speed steps, and are slower at the top end, with nice smooth accel/decel, too. The Genesis units are racehorses by comparison, and clearly have NO accel/decel time, so I set them to match the Bowser at 20 (after playing with other settings). I lowered min voltage on the Athearn units to 0 because they move at speed step 1 and the Bower doesn’t move till speed step 2 (which I apparently cannot find any adjustment that will start them moving at 1). I lowered (Athearn) max voltage to 190 and medium voltage to 60. This all was after 2 hours of playing around with them trying to get them to match.

So after 2 hours I have adjusted the Athearn settings to max voltage 190, medium voltage 60, accel/decel time 20 each, and min voltage 0. They will run together now, but I think I can still make some minor adjustments. As speed is increased to step 28 the Bowser unit starts to pull away slightly, but at slow speed the Genesis may still be a little faster.

I’m trying to get them to match as evenly as possible at all speed steps.

Is there something I am missing?

2

If I can get them dialed in correctly, these power sets could operate together for years.

3

PS It seemed that at any minimum voltage setting at or above 1 that the Genesis units were starting just too fast.

4

Well, after further testing, I now have the following settings for CV3, CV4, CV5 and CV6: 25, 20,160,48, for the Genesis Unit. Bowser unit is still 20,20,255,88.

Very different speed curve for the Genesis unit relative to Bowser. Not bad, just different. I like speed and the Genesis 2.0 units will roll a freight train.

The engines are matched very well on the low end between speed steps 4 (of 28) and 9 or 10. At 14 they are close but the Bowser starts to pull away slightly, and at 28 the Genesis unit seems almost even.

Since most of the time I will be operating between speed step 10 and 22 or so, I may try a couple more minor adjustments but they are actually getting close now. I just don’t want them fighting too much and prematurely wearing wheel plating off–especially in any kind of emergency stop when cat jumps on layout. Also, I want them smoothly accelerating and decelerating together. After setting the CV 3 and 4 to 25 and 20 respectively, the 25 helps to slow the fast start of the Genesis unit just a bit till the Bowser gets rolling, and the 20 helps the Genesis unit to slow to a complete stop in about the same time as the Bowser.

It has taken me almost 4 hours of adjusting and testing to get them running as closely together as they are.

If there is a better way or if adjusting PWM will help, someone please let me know. Thank you.

John

5

John,

If you want to really fine-tune the speed curve for each locomotive you can always implement speed tables - i.e. CV67-CV94. That said, if you get “close enough” with just adjusting CVs 2, 5 & 6 - that should be good enough.

Tom

6

Noticed all three of my recent Genesis acquisitions are quick out of the starting box. Two GP 38-2 and the recent GP 9 III

7

You should do some speed matching with the engines coupled together and with a train behind them. That will be different from just the two engines. I would imagine the lead engine will always appear to run faster, and if uncoupled from the second engine, will just run away because the second engine is pulling a train.

Also, remember that if you have a fleet of identical engines, the DCC settings won’t all be the same.

8

Thanks for the replies.

I now have the 2 Genesis 2.0 units set with exactly the same CV settings and they are matched well with each other and the Bowser SD40-2.

I put them to work tonight and they did pretty well together.

John

9

A little late to the party here, but for ATHG Tsunami2 if you set CV215 to 15, it will slow them down from starting creep and throughout the curve. I like switching so that is the first thing I do with the T2 Genesis.

If Bowser’s run slower, setting T2s right away might get you to a place closer to begin with before having to make the subsequent adjustments.

Again, a bit late to the party here.

10

CV5 is the engines speed at full throttle , CV6 is speed at 1/2 power. Part of the problem you’re having may be because the Bowser unit’s CV6 isn’t 1/2 of CV5. It’s set so that at 1/2 power the engine is going about 1/3 top speed.

You can set engines that way if you want - in theory at least it gives you more control at slower speeds - but can make it a lot harder to speedmatch. I find it a lot easier to not use CV6, I just set it to 0. Then you have a straight line speed “curve”, where each of the speed steps increases speed by the same percentage.

You can always slow an engine down by reducing CV5, but you can’t speed up a slow engine beyond CV5’s top setting. It’s usually best to determine with CV5 at full (255) to determine which of your engines are the slowest, and slow down the others to match. The slow engine is your “golden engine” that the other engines are adjusted to match.

When I’m speedmatching a new engine, I use these settings first: CV2 = 0, CV3 and CV4 = 20, CV5= 200, CV6 (if available) = 0. Then I put the two in a consist with the lead engine being the new one and see how they run together. I then use programming on the main to change the CVs of the new engine. Often, since my ‘golden engine’ is pretty slow, I make a big reduction in CV5, like by 50 or more, then fine tune it so the two are running at the same speed. Then I adjust CV 3-4 so the engines start and stop together. That process usually takes about a half hour or so.

11

The engines have rather different speed curves.

I elected to retain the Bowser settings because I have more Bowser engines coming during May and June of this year, so I only wanted to change the Athearn Genesis units as my son has only two of them.

The Bowser Loksound 5 settings are slightly different from earlier Bowser engines of the exact same model (SD40-2), too.

12

That’s why I find it works out best not to use speed curves. You can speed match engines just as well - and much quicker / easier - just using CV 2,3,4 and 5.

13

It became common knowledge or urban knowledge years ago that running engines with differing speeds would burn up the motor in one of them. I questioned that and asked anyone who had that happen to them to say so. No one responded so I think speed matching to a large degree is not necesary. I am welcome to opposing facts.

14

I don’t think you’d burn up the motor as long as the faster engine isn’t so heavy that it’s wheels can’t spin freely while it’s trying to drag or push the slower engine around the line.

However, since it’s so easy to speed match engines in DCC, I don’t see why anyone wouldn’t want to do it?

15

Douglas–

Thank you for the CV 215 suggestion. I did try it and it got me “closer”, but after many hours of adjusting I am actually unable to find any settings that match close enough through the entire speed range of the two locos. The earlier settings I tried do not work or only work for a very long, heavy train. They do not work for a shorter train length: at various points in the speed steps one unit is pushing or dragging the other and you can hear the wheels slipping and grinding when they fight each other and even some gear noise. I’m not going to trash these attempting to match them (already lost some wheel plating on these practically new units). Either I’ll get some more help from someone more knowledgeable, or I’ll give up (and only run Athearns together and Bowsers together).

Although I can get the speed tables for the Athearn Genesis 2.0 units from the Soundtraxx website, not knowing the Loksound speed tables at all is not helpful.

I’ll post something on the ESU forum, but I have to wait several days for approval to be able to ask a question.

Thank you Soundtraxx for spelling out the speed tables on your website! That is helpful.

John

VERY frustrated with speed matching in dcc, and yes, I tried to do top speed and middle speed/voltage separately as well as looking at everything in between…over MANY hours now.

16

bump - edited last reply. Perhaps someone else can point me in a more helpful direction? Thank you all.

Sincerely,

John

17

Is your primary goal to set up the engines with some unusual speed curves, or do you just want the two engines to work well together?

If the latter, adjust CV29 on each engine to turn speed tables OFF, then set CV6 on each to -0-. Then use CV5 to adjust the speed of the faster engine to slow it down so it matches the other engine. The decoder will create a “straight line speed curve” so both engines should run the same (or at least very very close) at each speed step. Then use CV3-4 to adjust the starting and stopping momentum so both engines start and stop together…if one is really sluggish starting, you may need to add a value to CV2 also.

Sorry to beat a dead horse, but you’ve been working for two weeks on something that should take half an hour.

18

Hello Stix–

Yes, thank you for your reply. I am well aware it should only take a half hour, and I have 6 or 8 hours into this, at least.

I will have a big fleet of Bowser engines, and they actually run, accelerate, and do everything more smoothly than the Athearn Genesis 2.0 units. Since I will have many more Bowsers than my son’s Genesis 2.0 units, I would prefer to adjust only the Genesis units to match the Bowser units.

The engines run very differently. When you get them matching at one speed step–say 28, then at speed step 14 the Bowser is pulling away and just leaving the Genesis in the dust. When you adjust the mid voltage to get them “almost” matching at speed step 14, then at speed steps 2 through 8, the Genesis unit is pushing the Bowser too hard such that wheels slip and grind, etc. AND the Genesis unit may pull up and catch the Bowser between 14 and 28, going too fast for the Bowser on the high end.

I have followed the available guidance and manuals and adjusted speed CV’s 2,3,4,5,6, and 215 (as suggested above). The engines are so different that I have not been able to get them to behave together.

Bowser default settings are CV5=255 and CV6=88. I have no idea what the Genesis default settings for the SD90MAC-H are, but I can get the speed tables from Soundtraxx. I have absolutely no idea what the Loksound speed tables look like for the Bowser–cannot find on their website or on ESU.

In plain dc, I can throw engines on the track and find better matchups in 5 minutes flat than this (but not with the SD90MAC-H). In plain dc, the Athearn Genesis GP38-2 is almost a dead perfect match to the Bowser SD40-2 such that they run very well together–AND oddly enough much better than anything I’ve been able to match in dcc.

So for all the “promise” of dcc being “better” than plain dc, it seems I have found 2 units

19

I know DCC can be frustrating, but you’re trying to do something really complicated by taking engines with an odd speed curve and trying to adjust other engines to match it. It’s better to adjust all of your engines up front.

First, check the instructions for each decoder and set CV29 (or whichever CV is needed) to turn speed curves off on all your engines.

Then adjust CV2 and CV6 to zero on all your engines.

Then adjust CV5 to let’s say 200 on all your engines.

Then try running them together. You can adjust CV5 up or down a little so they all run at the same speed.

Then you can use momentum CVs (3-4) to help them ramp up to speed and coast to a stop together.

20

So disabling the speed curves entirely will force all the units to respond in a linear manner?

I really, really wish that was explained in the manuals for the units. It is not, and both manuals refer the user to the manufacturer’s website.

Also I read through the entire NCE manual, and either it’s not discussed or I missed it.

Thank you Stix.

John