Fixing BlueLine decoder programming woes

EXPERT TRICK: Fixing BlueLine decoder programming woes by Joe Fugate


If you have purchased one of Broadway Limited's new BlueLine series locos and are trying to run it on DCC, then you have learned the loco only comes with a sound decoder and that you need to add a *second* decoder to the loco to control the motor.

BLI took this route to economize on the loco price, saving the cost of a motor decoder. The problem is now you have two decoders in one loco and the CVs overlap just a bit -- so you can't independently set the CV values in one decoder without also setting that same CV in the other decoder -- unless you use some sort of decoder locking technique.

The NMRA came up with a scheme using CV15 and CV16 to implement "decoder locking". First, you need to have only one decoder in the loco to start with (the sound decoder in this case), then you set CV16 to some number like 2 (the recommended standard "unlock" number for a sound decoder). Then you set CV15 to the same value (a 2) and that unlocks the decoder. Once you're done, you set CV15 to some other number, like zero, and that locks the decoder again.

On a locked decoder, the only CVs you can set are CV1 (the short address) and CV15 (the unlock code). All other CVs, including CV8 for decoder reset, are locked and cannot be changed.

Next, you put the motor decoder in, and set CV16 to 1 (the recommended unlock number for a motor decoder). Since the sound decoder is now locked, the 1 you put into CV16 only goes to the motor decoder, so you're good. Finally, you set CV15 to 1. This will set CV15 to 1 in both decoders (remember CV15 is one of the two CVs you can still change in a locked decoder).

Since CV16 is 2 in the sound decoder, CV15 (which is 1) does not match CV16 which is 2, so the sound decoder remains locked. However, CV16 in the motor decoder is 1, so setting CV15 to 1 unlocks the motor decoder and you can program away to your hearts content.

Decoders shipped from the factory have a zero in CV15 and CV16, which means the decoder comes unlocked -- since CV15 and CV16 match (they're both zero).

There is one big problem with this whole scheme, however. You can't program CV19 in a locked decoder, so making your sound decoder part of an advanced decoder consist with your command station doesn't work! The sound decoder is locked, so the sounds won't respond to your consist. Yet if you unlock both decoders, you can quickly have a mess on your hands with the CVs that overlap.

There is a way out of this mess -- and that's to forget using the whole less-than-adequate CV15/CV16 locking scheme and to use a trick that I describe below.


The trick to getting multiple-decoder programming work and yet allow full access to CV19 for consisting is to make both decoders have the same 4-digit address, but have different short addresses in CV1. Before we get into the details of the technique, here's what I do to make sure no other loco on the layout has address conflicts with the short address.


First, I keep track of the last two digits of the loco numbers of all my locos in an Excel table. This is important because I run almost all locos on my 1980s SP layout in consists, and consists can only be two digits (yes, you can also do consist numbers from 100-127, but who bothers with that ... 01-99 is simpler). If I have more than one loco with the same last two digits, I just make sure all of them but one is in the middle of a consist. I also make sure no loco ever ends in 03 on the end of a consist, since that's the number all new decoders come set to, and could cause problems when programming a brand new decoder.

Next I make sure all locos routinely use 4-digit addresses. My new NCE system lets me address consists using the 4-digit addresses of the end locos, although it also asks me what the real two-digit consist number is, and I pick the last two digits of one of the end locos as the consist number. I know I won't have any conflicts because I kept track, remember.


Let's say my BlueLine loco number is 4411. Here's the process I use (all done with programming on the main unless otherwise stipulated):

1. Put the brand new BlueLine locomotive on the track with no motor decoder in it yet, just the pre-installed sound decoder.

2. Set the long address of loco 3 to 4411.

3. Put 06 into CV29 of loco 4411, just to make sure the decoder is still using the short address. Remove the BlueLine loco from the track temporarily.

4. Install the motor decoder into a different loco temporarily and put it on the track.

5. Set the motor decoder to long address 4411 and short address 11.

6. Put 06 into CV29 of loco 4411, just to make sure the decoder is still using the short address.

7. Move the motor decoder into the BlueLine loco and put the BlueLine loco back on the track.

8. Now I can program loco 11 (the motor decoder) with whatever CV settings I want, and program loco 3 (the sound decoder) with what ever CV settings I want.

9. Once I'm all done and am happy with the settings, I put something like 34 into CV29 of loco 11 and in loco 3. This sets both decoders to loco address 4411, and now they act like one decoder.

This has the significant advantage that programming CV19 to form a consist goes to *both* decoders. I can make and break advanced decoder consists with my command station (which is doing it by programming CV19) and know with confidence that both the motor decoder and the sound decoder will be in the same consist and will respond to functions sent to the CV19 address.

See Joe Fugate's Siskiyou Line (external link)