Making locomotives in a consist run at the same speed

[Missouri Pacific BNSF]

 

I am trying to create a consist between two Bachmann DCC DD40AX locomotives; one has sound and the other does not, everything is factory and untouched.  I am having no trouble creating the consist (I am using the MRC Prodigy Express system) but I can't get the speeds to match.  I assume the sound locomotive is pulling more power thus making it run faster and start running sooner.  I am familiar with the CV system but I am not comfortable with it.  Can anyone dumb it down for me with how to get both locomotives moving on speed step one and also how to get them running at the same speed throughout?  What are typical CV number range values for startup and speeds?  Thanks! 

[jrbernier]

  This is going to depend on the actual decoders that Bachmann has installed in the models.  I suspect the sound engine has a Tsunami decoder, and the non-sound engine should have a low-end Lenz decoder in it.

  Normally, I start with the starting voltage(CV2) - You want the engine to just start moving when you advance the throttle from off to the first notch.  You can do this 'On the Main' and check your work after making a change. The value you need to enter depends on the individual engine - they are not all the same(even the same model).  I have 3 identical Kato SD40-2's - One starts moving with a value of 6 in CV2, another with a value of 10, and the last one has a value of 12 - All from the same production run.   Do this to both engines - They should now start about the same position on your throttle.  A lot of decoders have CV5(Vmax) and CV6(Vmid) that you can adjust for top speed and mid speed.   Here is a web link to the sound decoder CV's in the DDA40X:

http://www.soundtraxx.com/factory/OEM%20pages/bachmann/ho_dd40ax_sv.pdf

IIRC, the lenz decoder may not have these CV's.  You are stuck enabling the speed tables and adjusting the 28 speed steps(a real pain).  This is where having a system that supports JMRI is really handy.  MRC has chosen to not supply the source code to JMRI, so that is not an option.  You might inquire if someone near you has JMRI and have them set up the speed tables - It goes pretty fast using JMRI on a computer.  Here is the web link to the Bachmann 'DCC on Board' non-sound decoder:

http://www.bachmanntrains.com/home-usa/ez_content/1_Amp_Decoder_Instr.pdf

Jim

[Missouri Pacific BNSF]

Thanks!  My plan is to set both locomotives CV2 to "0" and start working up a CV unit at a time.  The sound decoder locomotive is already there (0) according to the above link you have provided.  The other locomotive has a default CV2 of 10.  Once I place both CV2 values at "0" do I start working up a CV unit at a time on the sound or nonsound locomotive until they are running and starting consistantly?

[kevinrr]

Here is part one of a five-part series on locomotive speed matching.

[jrbernier]

  I would get brave and increase it by 10, then test...  You can always ramp it down.  Some decoders need lots of increase in CV value, others, not too much.  I suspect you sound engine starts at a much higher voltage(normal).  Ig it does not start moving at the first click of your throttle, it's time to increase CV2's value.  I have only one engine actually start moving at speed step 1 on my throttle out of the box(Atlas Master GP38).  Even my super running Kato engines have needed a little adjustment.

  A tip before starting speed matching.  Let the engines 'warm up' by letting them run around the layout for about 20 minutes.  This will get the stiff gear lube warmed up....

Jim

[wjstix]

If the sound-equipped engine is the faster one, it's pretty easy to slow it down using CV 5 (top speed) and CV 6 (mid-speed). I don't believe the inexpensive decoder Bachmann puts in it's "DCC Equipped" engine uses these CVs, so you won't be able to change that's engine's speed (except fine tune the start speed and momentum). In the long term, it's probably better to spend $20 or so for a good TCS, NCE or Digitrax decoder to replace the one in the non-sound one.

[rrinker]

 Since they are the same locos, consider a TCS T1 in the non-sound one. I have a pair of Stewart FTs, one with a T1, one with a Tsunami sound decoder. I didn;t have to adjust anything, the self-adjusting BEMF on the TCS decoder got them running pretty well together right out of the box. They don;t have a choice - they are now drawbar connected, but I don;t have one dragging the other on start, or one sitting there spinning on stop.

           --Randy

 

[Missouri Pacific BNSF]

Thanks for the help guys.

[JBs UP]

Were you ever successful creating the consist with the OEM decoders. Like your situation, I have one sound and one non-sound and need to speedmatch. What settings did you use for each?