# A-B-B-A Question



## bonez (Feb 2, 2014)

I have the recent MTH Alco PA A-B locomotive set with DCC and want to add another A-B. However, they do not make a second set with a different road number. So can I use a duplicate numbered set lashed up to the current set and use DCC? 

I have always read that an engine is assigned its DCC address from the road number. Hence my question about lashing up duplicate engines.

Can I assign them as 70, 71, 72, 73 (the A-unit is 70 there is no number on the B-unit)?

Thanks - this is all new to me.


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## gunrunnerjohn (Nov 10, 2010)

I removed the other identical post, please only post once for a specific issue. If there's a reason to move the post, you can click on the red triangle







on the lower left of a message and request it be moved.


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## dave1905 (Jul 7, 2013)

In DCC you can set the DCC address to be anything you want in the digit range of the system. Most people set the address to be the road number just to make it simple. If you consist all the units together, you can use the consist number to control the units.


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## Cycleops (Dec 6, 2014)

The number you program is your choice and be anything you want. You can easily buy a decal sheet for your road which should contain the nessecary numbers. Use a cotton bud dipped in T-Cut (an automotive compound for cutting paint back) or another brand to remove the existing letering. Its not very aggressive and shouldn't affect the paint underneath.


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## bonez (Feb 2, 2014)

*Help Needed*

So I finally placed my MTH Alco PA units on my layout. I am using NCE system and am having difficulty getting them to run properly. 

I ended up taking my units to a local train store for programming help. What he did was program the front A-B units simultaneously setting the address to 60. Then he programmed the second set to address 61. Then he consisted them together using address 112. 

It seemed to work fine at the store. But I am having problems when I run on my track.

First is that I cannot get the horn, bell and light functions to work.

Second is that I have to first select loco 60 then select loco 112 for the consist to run.

So my questions are:

1. Should the A-B pair be addressed simultaneously or separate?

2. Should I reset everything to factory setting and start over? 

2a. If so then should I separately address each unit (say 60,61,62,64) and then consist together as four individual units?

Any help with programming MTH with NCE I'd greatly appreciated.


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## Cycleops (Dec 6, 2014)

I’m not much of an expert on consists but I did have a NCE system so you’ll have to bear with me. Does your MTH decoder support advanced consists? According to NCE the consist is identified by the lead loco and will still accept commands for horn bell etc. Each loco in the consist will respond to functions as originally programmed. Refer to page 25 of your manual.
I don’t have any experience of MTH decoders so can’t comment on how they might act differently on a NCE system if indeed they do.
I think you best option is to contact NCE directly, they are usually very helpful and I’m sure will have the answers you need.

Good luck.


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## bonez (Feb 2, 2014)

Success. I cleared the consist and then re-addressed each unit to a short address (60,61,62,63). Then established a new consist and all works well. 

Was actually very easy with my NCE system.


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## Cycleops (Dec 6, 2014)

That’s great, glad you got it sorted.


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