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Consisting: Using same decoder address

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Posted by richhotrain on Monday, September 2, 2019 8:38 AM

Speed matching?  I thought that this was a thread about consisting.

But, since we are on the subject of speed matching, I almost never do it. But I have had a few instances where two identical locos from the same manufacturer run at different speeds. In those few instances, I do what South Penn does - - test by setting locos to be speed matched on parallel tracks.

Rich

Alton Junction

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Posted by rrinker on Monday, September 2, 2019 1:22 PM

 Same as I said in my previous reply - all those that say speed matching is absolutely required, were you doing any model railroading prior to DCC? The club I belonged to way back when is now even bigger and all DCC, but it was strictly DC when I was there, DCC was just being talked about (well, an NMRA standard command control system that is). For open houses, most people just like to see stuff mooving. Stopping, backing up, dropping cars in sidings, that sort of thing bores the casual visitor. So we ran multuple long trains in each direction. 2, 3, even 4 power units on the head end. Speed matching? There is no speed matching in DC, unless you want to use rather large jumps of .7 volts and try to fool around with diodes. We just ran 3-4 of the same brand loco.

 DCC changed none of that, it just gives MORE options. Two locos of the same brand, with the same decoder, will run fine together with no adjustments, unless one is broken or someone really fiffled with the CVs on one decoder. What we get with DCC is the ability to freely mix completely different locos because we CAN speed match - even then, in many cases the same manufacturer will use the same chassis and drive train and fit different shells to make a different model loco, so those still probably don;t need speed matching. When it's different manufacturers, across different eras, so they have different motors, different gearing, etc - they may not run well together, so there you need to do some speed matching.

 And when I do - it's always through the simple 3 steps of CV2-6-5. I won't run any decoders that don't support CV6 for mid voltage. I have yet to find any two locos that need a full 28 step speed table set up to actually run together. Perfect lockstep was not needed for DC, it's not needed for DCC. 

 And if you don't have parallel tracks, just put both locos on the same track, with say a gooot or so between them. Then you can adjust so they don't get further apart or closer together. 

                                        --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by wjstix on Tuesday, September 3, 2019 10:22 AM

rrinker
Same as I said in my previous reply - all those that say speed matching is absolutely required, were you doing any model railroading prior to DCC?

I guess the question I'd ask in reply is, since it's so easy to get all engines to run the same now on DCC, why wouldn't someone do speedmatching? It's kinda like saying 'well it's 100 degrees out, and my car has air conditioning, but I won't use it since my first car didn't have air conditioning.'

Yes, I was in model railroading about 30 years before switching to DCC. I found Atlas HO engines would generally run well together, and once in a while you'd get lucky and two engines from other manufacturers would work OK together. Some folks spent a lot of time and effort adding resistors to their engines to slow a fast one down so it sorta/kinda ran at the same speed as another engine.

 

Stix
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Posted by rrinker on Tuesday, September 3, 2019 2:03 PM

 Because it takes a lot of time to match across all 28 steps of a speed table, especially when you are already using a DCC system that defaults to 128 steps, not a mere 28. For little to no gain.

 I'll save the speed matching for when I want to vastly different locos to run together - then it makes absolute sense, because it allows you to do somethign you can't do with plain DC.

  In the end, most of my locos will be effectvely speed matched anyway, as all the ones that run way too fast as full throttle with have CV5 set to keep the top speed to a realistic value. I may also set the mid speed to create responses suited to the type of service the loco is made for - quicker acel for a passwnger loco, slower for a drag freight loco.

                                --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by York1 on Tuesday, September 3, 2019 3:17 PM

I have found the biggest issue is for acceleration -- deceleration.

I've got locomotives with different decoders that matched speed fairly well, but when I set the acceleration the same for both and ran them in consist, you could hear the wheels on one slipping while it accelerated faster than the other.

It's easy to fix -- took about 5 minutes, but it still needed to be done.

I love the acceleration -- deceleration settings.  I know others who want to control every inch of speed, I like to set a speed and have the locos slowly acc. automatically.

John  --  Saints Fan  

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Posted by rrinker on Tuesday, September 3, 2019 4:24 PM

 Yes, different decoders brands use different ranges for the momentum values, so a value of 10 on one decoder might need to be 40 on another to be equal.

 ANother good reason to standardize on decoders - I don't think I will be buying any more TCS motor decoders for non-sound locos, instead I will get Lokpilots to match the Loksounds in all my sound locos - in addition to all the CVs being the same that way, hen I can also use the Drive Hld on Loksound even if all the locos don;t have sound, because Lokpilot respects the option even though there is no sound to rev up/down.

                                             --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by pennwest on Thursday, September 5, 2019 7:23 AM

One interesting use of consisting is for a local train switching an industrial park with both leading and trailing spurs and no run-around. The train has a switcher at each end, running consisted to the park, then broken to use one loco for leading moves, the other for trailing. With a Digitrax 400/500, one throttle has the lead loco, the other the trailing one, and consisted, one throttle runs both. Two button presses to consist or unconsist. No address swapping on the throttle needed. Neat.

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Posted by rrinker on Thursday, September 5, 2019 7:43 AM

 That is an example where consisting makes more sense than giving both the same address - to replicate that typical prototype practice.

 It's not an all or nothing scenario. It just makes very little sense to use coonsisting when the two locos are coupled with a drawbar and can;t be run independently anyway. Now, if the are TWO sets of A-B units, each A-B drawbar coupled, and you want to run A-B-B-A, now you consist the two sets together, because the sets can uncouple from one another and pull another train as just a single A-B set, or combine with another spare B unit, or another spare A unit and run A-B-A or A-B-B. 

 It all depends on when you are modeling - in the early days of F units when drawbar coupled units were common, the usually stayed together. Seemed to make sense - they had the same inspection and maintenance intervals, so why break them up? Then later the railroads realizes that any fiven B unit fo the same model (FT, F3, F7, etc) was the same as any other B unit of the same model, so if one B unit was down, any available B unit could substitute to get the required horsepower to haul the next train out. Drawbars were repalced by couplers and units could be freely mixed and matched for maximum availability - sitting a working A unit because the drawbar couple B unit was down for repair was an expensive proposition. ANd as the MU systems became standardized across manufacturers, you started to see the really odd lashups that weren't even possible a few years earlier. 

                                     --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by wjstix on Thursday, September 5, 2019 8:31 AM

rrinker
Because it takes a lot of time to match across all 28 steps of a speed table, especially when you are already using a DCC system that defaults to 128 steps, not a mere 28. For little to no gain.

Um...what? You don't have to speed match each step separately. I don't use speed curves normally. I use CV5 (top speed) to adjust the speed up or down. The DCC system automagically fills in each step (whether 14, 28 or 128) in between step 1 and the top step. CV2 can be used to adjust the starting speed so both engines start together, then use the momentum CVs (3-4) to smooth things out so the engines slowly ramp up to speed and gently coast to a stop together. Doesn't take all that long.

Stix
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Posted by rrinker on Thursday, September 5, 2019 11:47 AM

 You're agreeing with me more than you're not - been my point all along that the start, mid, and top speed settings are all you need to get locos plenty close enough for the ones you do have to speed match. If needed, that's all I do. I do have some VERY different locos that run well together with no adjustments at all.

                                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Friday, September 6, 2019 5:03 AM

So, who uses speed tables and why?

Rich

Alton Junction

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Posted by gdelmoro on Friday, September 6, 2019 6:16 AM

Well ... to be honest I have been trying to get all my locos to match one   Master loco so that I could assign any loco to any train either in a consist or as a helper and they would run the same speed.

Why? Because that’s what I believed you had to do from what I have seen and read in Videos, articles, JMRI demos and forum posts that told me so.

Perhaps I was wasting my time.Indifferent  

Gary

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Posted by rrinker on Friday, September 6, 2019 7:19 AM

richhotrain

So, who uses speed tables and why?

Rich

 

 Anyone with Tsunamis since they don't support CV6 for mid speed. Just one of the reasons I switched to Loksound. Not sure what their reasoning was, as even the good old $11 D12SRJ from NCE supports the 3 step CVs.

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 11,411 posts
Posted by wjstix on Friday, September 6, 2019 9:21 AM

rrinker
You're agreeing with me more than you're not - been my point all along that the start, mid, and top speed settings are all you need to get locos plenty close enough for the ones you do have to speed match. If needed, that's all I do.

Yes but that's all anybody has to do to speedmatch. I've been in DCC 15 years, never heard of anybody speedmatching each step one by one to another engine. If the decoder is set to either not use speed curves, or to just use a straightline speed curve, when you raise or lower CV5, the decoder automatically adjusts all the speed steps in between the first (starting) step and the last (highest) step...even if the decoder doesn't have CV6.

Stix
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Posted by rrinker on Friday, September 6, 2019 11:23 AM

 Plenty of people TALK about it, if they aren't doing it. Making it seem like you HAVE to do it to run multiple locos in a consist. And then the DC guys just point and laugh at how complicated things are with DCC....

                                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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