I have a couple of MT sets of FT’s that are drawbar equipped. The “B” unit will have the same loco number but it must run in reverse given the way the decoder is oriented. How do I get around this and keep a prototype lashup?
Ideally, I think it would be better to use different numbers, so that you can MU the two and compensate for small changes between the units. Since they are a set, though, they may be well-enough matched to get away with a single address. If you swap the two wires between the decoder and the motor, the B unit will run in reverse.
CV29, Bit 0, determines the direction of travel of a locomotive. If this bit is set to 0, the locomotive travels in a forward direction; a value of 1 causes it to run in reverse.
To reverse the second unit’s motor, add “1” to the value programmed into CV29. Depending on the DCC system you have, there might be a programming option to reverse a locomotive’s direction without having to play around with the CV.
Even if they ARE slightly different in performance, you can still individually adjust the start, mid, and top settings, or define a speed table, to get them to run just right together, and still use identical addresses. Although, given that they are a set, they probably DO run quite nicely together right out of the box.
Cacole is correct, just add 1 to the value in CV29 to reverse the direction (odd number). Even values of CV29 run towards the front of the loco when in forward, assuming allt he wirign is correct. You want complicated> Try an A-B-B-A set - the lead A unit gets an even CV29, the first unit gets an odd CV29 value, the second B unit gets an even CV20, and the trailing A unit gets an odd. Thank goodness for programs liek DecoderPro that save all this stuff in a database for you. If you can’t or don’t use DecoderPro, these are the kind of things you shoudl write down somehere, because a month from now yu’ll never remember what odd configuration you put together to make it all work.
–Randy
As indicated above, CV29 is the answer. Been there, done that, and I’ve got the tee-shirt. I have 4-multiple sets of F7s on the BRVRR. One word of caution, don’t mix decoder manufacturers if you can avoid it. They are a bear to match.
I agree with rrinker. I have a set of Stewart FT’s with one difference…3 of them are powered but the first B unit is a dummy full of sound! What a team! For CV29 to use 2 digit addressesand 28/128 speed steps, the lead A and 2nd B are set at 02 and the tail A is set at 03. For four digit adressing the settings would be 34 and 35
That’s EXACTLY what I am planning to do with mine. I have an F7 A-B set, with the B being a dummy. I also have a spare B unit shell (arrived NIB broken, STewart sent me a replacement shell for free. A little raiding of the spare parts box (and some old Athearn shells) and I fixed it all up. I also modified an Athearn chassis to fit on it. So now I have a powered A and powered B, and a dummy B just BEGGING for some BIG speakers and a sound module.
–Randy)
rrinker, me again, a kindred spirit. check out Litchfield Station’, website. Bruce did a great job on mine, using a soundtraxx decoder, 2 woofers and a tweeter! I had to grind away a little bit of the inside roof where the framing of the dynamic brake housing is, Also you might consider opening the exhaust stack holes a little bit, because that decoder does run quite warm and is right up against the roof. Sounds great!!!
I’ve ordered some decoders from Bruce in the past. Great service. I figure this should be a much easier first time sound install than trying to cram it all into a powered unit. We’ll see, it’s a ways off, now I need to save my money for the PCM Reading T-1.
–Randy