RailPro > RailPro Specific Help & Discussion

Linking/Speed Matching

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Alan:
While, technically speaking, starting voltage should not matter for MUing, it sounds in your case it might. One at a time, not MUed, set the start voltage so each loco begins to move at no more than 5% throttle. It may help your MUing situation. My Atlas units right out of the box were typically 10-15% throttle to achieve movement.

Personally I set start voltages on my steepest downgrade on the layout with a long train behind (lightest possible load on a single loco). This way I know I can get movement with minimal throttle movement and without fear of jack rabbit starts when going downhill. The process can be a bit tedious.

I set all my locos to less than 5% because it makes the throttle response/position more uniform and predictable between different locomotives. My logic is there is no such thing as a powerless notch on a real locomotive running light. Plus, it just doesn't feel right when you nudge the throttle on a loco and nothing happens.

Alan:
The more I think about this the more it doesn't add up. If the wheels of the GP40 start spinning before the GP30 moves then that means the GP40 has already reached maximum current draw at least once. When the GP40 is at maximum the HC1 would also place the GP30 at maximum. They should both be flying down the track.

This is going to sound like a dumb question but are you certain you have them MUed correctly on the HC1?

Another dumb question... when the GP40 wheels are spinning are they spinning in the right direction? Is it possible the GP30 is dragging the GP40 backwards? Being the GP30 is so much heavier maybe the GP40 can't drag it the other way.

William Brillinger:
Another thought... Are the modules using the same software version?

If they are not up to date, you might want to update the software on the modules and HC.
Some older versions of the software did not play well with some other versions as I recall.

Dean:
Try this. Put both locomotives on the same track but do not connect them together, rather leave a gap of at least one locomotive length between them. Then MU them together if they aren't all ready. Remember, the first locomotive you picked for the MU setup is the 'lead' locomotive, and the rest will follow, speed wise. Now try running your MUed locomotives. ( you should be running from the 'lead' locomotive screen ) Do they both go they same direction? If not, press the 'MU=2' button on the HC screen. You can change the direction of the follower locomotive there. Now run your MUed set again, still not connected. Do they start at about the same time? If not, delete the MU setup and work on the locomotive that is not starting properly. I would pull the shell off first and check for mechanical binding. You might want to run it with the shell off so you can see whats happening.
When happy with the mechanicals tune the decoder to the locomotive.  If is a new locomotive, you might want to run it singly for 30 minutes in each direction. This will break in the locomotive and make the tuning easier.
Remember, the locomotives in a MU consist 'learn' to run together and follow the lead locomotive, but it does take a little time.
The great MU capabilities are the reason I started using RailPro.

Homeless by Choice:
Guys,

This is a very interesting problem solving discussion.  Thank you for the very informative step by step debugging process.  Please continue the discussion and be sure to post the final resolution in detail.  I was under the simplistic belief that you basically determine the max current, MUed the engines, and bingo you were done.

I am not one bit faulting the design or questioning my decision to invest in the RailPro system.  I just want to understand/learn all the logic and setup requirements so I can stay on top of any possible issues.  I am sure that this is MUCH MUCH easier than using a DCC system.

Thanks for the information,
LeRoy

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