Does JMRI have a tool for speed matching easily or automatically? I have speed matched before with a loop of track and had two locomotives chase each other until i got them to match but if possible I would like to avoid that in the future. Maybe someone has had some experience with roller stands and a speedometer. I have loksound and tsunami decoders so i can program each individual step if required.
Decoder Pro (JMRI) doesn’t “feel” how each individual locomotive react to any setting so no,there’s no automatic speed matching possible.It still is a trial and error process.However,DP allows you to see your speed curves.Visualizing makes it easier than tinkering with numbers wich makes DP a great tool.
Not automatically, but somewhat easily. My “railroad” is basically a loop. I have a speedometer installed. JMRI has a “speed table” tab that has 28 vertical bars that represent 28 speed steps.
I set the top speed I want for a loco. In my case that’s 60 smph as measured at the speedometer. I adjust the value of speed step 28 to achieve this. Then I adjust the value of speed step 1 to get the loco’s minimum speed where I want it. Typically I set this at 3 or 4 smph. Then I adjust the values of speed steps 7, 14, and 21 to get the quarter points where I want them. In my case that’s 15, 30, and 45 smph. JMRI has a function where it can interpolate all the other points in between and generate a curve. You can set all the points manually if you want, but I find setting those I mentioned works good enough for me.
There’s some other stuff I do, but the above summarizes the process.
You do need a speedometer to work efficiently. I tried the one engine chases another method and determined very quickly that it woudn’t cut it if I had to do more than two locos.
Maxman;
Can you provide more details on how you do that in Deccoder Pro. I end up having to adjust every speed step.
Thanks,
Mark
There are boxes under each speed step. Check the boxes you want and they end up being sort of pivot points for the table. Changing those steps will cause the steps in between to adjust automatically.
Peter
Mark:
As Peter above said, there are those little boxes below each of the 28 speed step vertical bars. As I mentioned above, what I do is get speed steps 1 and 28 where I want them. Below the speed step bars are a group of speed curve selections. I click on the one that says “match ends”. This will create a straight line curve between speed steps 1 and 28.
Then I click on the little boxes below speed steps 1, 7, 14, 21, and 28. An X or a check mark will appear in the box. This in effect locks those curve points. For me these represent approximately 3 or 4 smph for speed step 1, 15 smph for speed step 7, 30 smph for speed step 14, 45 smph for speed step 21, and 60 smph for speed step 28. As I mentioned I have a speedometer, so I’ll run the loco at speed step 21 and check to see if the speed is 45 smph. If not I’ll adjust the value of speed step 21 until I get the speed correct. You’'ll notice that if you change the value of one of the locked speed steps that the adjacent speed steps will change between the speed step you’re adjusting and the adjacent locked speed steps.
Depending on the loco, or really the quality of the motor in it, I’ve found that I sometimes get very lucky and little or no adjustment is required to any of the locked speed steps. Basically this means that the motor requirements follow that straight line curve that JMRI established. Other times not so lucky, and the motor will follow the straight line at the lower values, and then start to follow an exponential style curve for the higher speed steps.
One hint… when you get to the point where you have used the match ends function save the file. That way if you screw up and chan
Similar to Maxman, I use a speedometer.
What I have done different is I only use 3 points (steps 1, 14 and 28) because when I started to use the tables I was already using Vmin/mid/max and these 3 steps were close enough to simulate Vmin/mid/max. I like the idea of using more points but haven’t got around to doing it yet.
Also different is I don’t use the “rocket” speeds that Maxman uses 
, The maximum speed I use is 40 smph and a mid speed of 16 smph.
After dong a few locomotives you start to see the range where your settings end up at. You can start using those as your starting points before actual speed matching. For example, I normally set step 28 to around 165 for a starting point and step 1 to around 5. YMMV.
Peter
Thanks, that sounds like a good place to start. I suppose as far as chasing to speed match goes I could always make a master locomotive that I would match everything to. Because I have a mix of amtrak and norfolk southern I might set the top speed around 80ish and keep the throttle lower in a more reasonable speed range and then I can match NS Diesels with my J Class and my J class with amtrak if i need.
That’s a reasonable idea, until you come across one that can’t run as slow as the master, or won’t go as fast as the master, and you have to adjust hte master again.
The key thing to remember though is that close is good enough. Two locos chasing each other with no train will run differently than if the two are coupled together and then have a train to pull. Just because DCC has enough settings to allow you to make two locos run in absolute lockstep doesn’t mean you HAVE to do that. You certainly don;t want one circling the layout in half the time of th other, at the same speed step, but if one gradually pulls away from the other, it will still be OK. There was no speed matchign with DC, you jus tput a coupel locos together and away you went - DCC is really no different. I even run 2-3 loco consists where I have NOT turned off BEMF, and they don’t fight each other, they pull together to move the train. These run for hours at club shows with no overheating or damage, and all I ever did was make the most minor of tweaks to CV2, 5, and 6 to get them close. No time-consuming programming sessions to make them exact.
–Randy
Concerning the chasing to speed match method goes, I see a couple of problems. Aside from making sure that your “gold” loco is the slowest of the litter a both I and Randy mentioned, without a speedometer you don’t really have any idea how fast the loco is travelling. You can do this determination manually by setting a fixed distance on your railroad and using a stop watch and some math to determine scale speed.
So the process would be: 1. check the time throught the trap; 2. do the math to determine the speed; 3. adjust the value in the appropriate CV; 4. repeat steps 1 through 3 until complete. And that’s just the first speed step you want to set for the gold loco. Now you get to repeat this for all your other locos. Actually you don’t have to repeat for the other locos, you could just have then chase the gold loco. The problem is as the loco follows there will be some places where it will catch up and other places where it could fall behind. This has to do with variations in track geometry and voltage differentials. And again, you really don’t have any definitive idea as to the trailing locos speed other than “well that looks okay”.
Just my opinion, of course.
Regarding the “keep the throttle lower” to match the diesels to the steam locos idea, I don’t think this will work. Let’s say that the top speed of the diesel at speed step 28 is 80 and the top speed of the steam loco is 40, and that they both happen to have a linea