DCC and Loco Consist


meanjean

meanjean

Member
I have been trying to get three different locos with three different decoders to run in a consist.
1. Athearn rtr sd40t-2 with Tsunami
2. Athearn rtr sd40t-2 with Digitrax
3. Athearn BB sd40t-2 with Digitrax.

I have messed with starting v and can get them to run really close to the same speed at a crawl. When you increase speed they are all different.
Question is this. Is there a way to speed match the locos with out 100s of trial and error for each loco? Different decoders have built in pre set speed tables but none are the same correct? Mid volt and top volt I know will help and have been adjusting them also but every loco is different.

I need some advice on how to get three different locos to match speed through 28 steps.
 
Wow Im suprised nobody has input. What are you guys doing when running DCC consist? Do you not have issues of locos running different speed?
 
i don't have first hand experience but as far as i understand speed does need to be matched before MU'ing and that speed matching does take quite some effort. seems like lots of tries are unavoidable
frrom Consisting guide
http://www.tonystrains.com/technews/consisting-guide.htm

SPEED CONTROL

Regardless of the type of consisting you are doing the locomotives should run about the same speed when on the same speed step. You can have a "standard" locomotive then adjust the other locomotive speeds to match. The simple way is to use CVs-2,5,6. A more accurate way is to use the alternate speed table (CV67-94 with CV-29 bit 4 on). Even identical locomotives may not run at the same speeds.

CV-2 sets the start voltage for speed step 1, CV-5 sets the top speed (speed step 28) and CV-6 is used for the mid range. CV-2 is a Recommended CV while CV-5 and 6 are only Optional. Looking through a number of decoder manuals CV-2 is the most commonly used of these three CVs. The next most common is CV-5 and the least number of decoders also use CV-6.The range of values used varies with manufacturers. If you are going to use the alternate speed table I suggest using a computer program like Decoder Pro (free over the Internet). This allows you to set the alternate speed table using the mouse on your PC or Mac computer.

Speed matching can be done on either a loop of track or two parallel tracks. Run the standard locomotive and the test locomotive as a consist but not coupled together. When adjusting CVs you need to use the normal address of the test locomotive, then change the system back to the consist address.
 
Chad, what DCC controller are you using? Some, like Digitrax, allow you to set up a kind of "cruise control", where the consist speed is monitored and voltage is adjusted to keep all the engines near the the same speed. All the locomotives don't have to run at exactly the same speed. As long as all the engines run at nearly the same speed, they will do fine in a consist. You really only need to adjust speed tables if you have one engine that's way slower or way faster than the other engines.
 
I am using MRC Prodigay advance. I have the 3 locos start Volt all pretty much the same. Its just the locos all vary in speed throughout the 28 speed steps.

I dont expect them spot on just close enough to not cause problems while running.:rolleyes:


Chad
 
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