Front and Rear Ditch Lights

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diburning

AlcoHaulic
I will be getting 2 Athearn RTR GP40-2s, and 2 Athearn RTR GP38-2s soon and I will probably get ditch lights installed on the fronts and rears of the locomotives.

Three will be NS and one will be Conrail. As far as I know, all of the units have oscillating/flashing ditch lights.

Those locos will also be getting Tsunami decoders in them sometime in the near future. However, the Tsunami decoders only have 4 functions (Front and Rear Headlight, and 2 other functions) which would mean that the Tsunami would only be able to drive the front ditch lights.

I am thinking about putting in a second function only decoder so that the rear ditch lights would flash as well.

My questions are:

1. Would I need a 4 function, function only decoder?
2. If so, which brand does the best job?
3. Which brand is the least expensive?

4. Would I be able to use the Tsunami's 4 functions for the ditch lights and put in a 2 function, function only decoder for the headlights?

5. Would I run in to any programming problems with any of these setups?

6. Do you have any other suggestions?
 

fiend540

Member
Not to hijack your thread but I want to do the same thing and I am wondering what brand of ditch lights you plan on using.
 

diburning

AlcoHaulic
It's up to which style and which road. Railflyer makes some really nice ditch light castings, but they aren't in stock since they haven't produced any in a while.

Detail Associates castings are true to scale, but they are plastic.

Details West makes pewter castings, but they are a bit thick. You won't see the difference unless you're a rivet counter though.

Depending on the size of the lights, I'd either get a lens and put a bulb behind it, or if it's pilot mounted, I'd just use the end of the bulb.
 

UP2CSX

Fleeing from Al
I can't see any reasonable way to have two different decoders in the engine if they are both used for lighting. You need to have a unique address for the decoder and your controller is only going to see one address. Someone smarter than me may come up with a way to piggyback two decoders but I can't see how you would be able to program them both in the same engine.
 

diburning

AlcoHaulic
Jim, as long as both decoders are set to the same address, both decoders will program at the same time and both decoders will respond to the same commands since they are the same address.
 

ncmrdispatcher

A&O Historical Society
In larger scales (I'm in O 2-rail) we often require a pair of decoders with both set to the same address. Here are two common alternatives for doing the decoder programming:

PROGRAM BEFORE INSTALL
Install one decoder and program it. Prior to installation, program the second decoder. However, future programming changes can require opening the unit and disconnecting one of the decoders if the two decoders require different values in the same CV.

CV 15 & 16 DECODER LOCK REGISTERS
Before installing either decoder, program each with a unique programming lock ID code in CV 16. For example, the Tsunami might receive an ID of 0 as the "primary" decoder and the accessory lighting decoder an ID of 1. After both decoders are installed, program the Tsunami by writing a value of 0 to CV 15. The accessory decoder will ignore all programming because in its memory CVs 15 and 16 do not match. To program only the accessory decoder, write a value of 1 to CV 15.

Since most modern decoders support decoder lock in CVs 15 and 16, as does the Tsunami, "lock" may be the easiest way to go. This is discussed on page 10 of the Tsunami Diesel manual which you can download from the Soundtraxx web site. Mapping the function outputs using CV33 through 46 starts on page 24. How to set up functions as ditch lights starts on page 29.

In HO you will probably need to select the auxiliary decoder based upon physical size. If I understand your situation correctly, only two more lighting functions are needed and these can be headlight/reverse light. If that is the case, any two-function decoder that supports "lock" would work.

Hope this helps.
 
Last edited by a moderator:

MGWSY

Active Member
You can put 2 decoders in to the same loco but as stated you will have to program each one individually. I have a couple locos that have a NCE DASR for motor control and lights with soundtraxx decoder for sound. It takes some time to get everything working but worth it in the end.

You might be better off getting a TCS 6 func decoder for motor and lights and use the sound decoder for just sound. I have never installed a tsunami yet so I cant comment on how to program it and if it will actually work. As for function only decoders you have to make sure that all the functions support lighting features as some are simple on and off functions so you cant do flashing ditchlights with them.
 
The advantage to using the decoder lock CV's is that you can still do programming on the programming track, the disadvantages are that not all decoders support it and it's implementation is not completely the same among the decoders that do(for example, Tsunamis require setting a bit in CV30 to enable decoder locking, and if you use TCS decoders you can not use 0 in CV16 for locking because if CV15 is 0 the decoder will be unlocked no matter what the value in CV16 is).

The are two more methods that require an initial programming of the decoders before installation and then allow for subsequent, but they do require the use of Ops mode programming. One method is to give the two decoders different addresses and run them as a consist. The other method is to give them different primary(or short or 2-digit) addresses but give them the same extended(or long or 4-digit) address. To run the locomotive, program CV29 to enable the extended address and run the locomotive using the common address. To make any program changes, program CV29 to disable the extended address and then do ops mode programming to the separate primary addresses. If you would prefer to run the locomotive using the primary address, you could give the decoders the same primary address and different extended addresses and use the extended addresses for programming.
 

UP2CSX

Fleeing from Al
See, I knew there were people smarter than me about these things. :) I think Robert has come up with the ideal solution. Program each decoder with a different short address before it's installed and then use the same long address for both when they are installed. Since the non-sound decoder will only be used for two lighting functions, you should rarely have to change CV's once they are initially programmed. Select the Tsunami short address for changing CV's and the other decoder should ignore the commands since it has a different short address. This is a little easier than consisting and gives you access to both decoders without having to open up the engine. Good thinking, Robert.
 

diburning

AlcoHaulic
The problem with that is that I will be running these locos down at the model railroad club. Any short or long addresses will overlap at some point and intefere with operations (for example, we have 6 locomotives with the road number 200, and only one can actually have an address of 200 and remain on the layout)

I think I'll just do the locking method.

But one question hasn't been answered. Can the tsunami use all 4 functions for ditch lights or be remapped for ditch lights or are the first two functions set for constant?

Also, if I want to alter the flash rate for the ditch lights, how would I program that, and do I need to do anything special since there would be 2 sets of ditch lights?
 
The problem with that is that I will be running these locos down at the model railroad club. Any short or long addresses will overlap at some point and intefere with operations (for example, we have 6 locomotives with the road number 200, and only one can actually have an address of 200 and remain on the layout)...
That shouldn't be a problem, the decoders will only respond to the one common address while you are operating. The only time they will respond to the other addresses is when you program CV29 to specifically tell them to respond to them. As an example, if you program the Tsunami to a primary address of '4' and the function decoder to a primary address of '5' and program both decoders to an extended address of '1234', while at the club both decoders will only respond to extended address '1234' so if there is another loco with address '4' or '5', it won't matter. If you need to change the common address of the decoders, you can do that on the program track and it will not affect the other addresses.

This part would be no different than any other decoder on the layout. All modern decoders have two addresses, a primary address and an extended addresses, but they only respond to the one that is currently enabled.

...But one question hasn't been answered. Can the tsunami use all 4 functions for ditch lights or be remapped for ditch lights or are the first two functions set for constant?

Also, if I want to alter the flash rate for the ditch lights, how would I program that, and do I need to do anything special since there would be 2 sets of ditch lights?
If you don't have the Tsunami Diesel Technical Reference, then I would suggest downloading it. The Tsunami has a separate CV(49-52) to select the effect for each ouput, so I don't see any reason why you could not use all four for ditch lights. There is also a CV(59) for adjusting the flash rate.
 

diburning

AlcoHaulic
I have downloaded the manual, but not quite sure on how to map the 2 functions to 1 key so that I can turn them on and off but have them blinking when the horn is blown, especially to set them up directionally.

Is CV 59 used to adjust the flash rate for all of the lights?

I don't know much about programming CVs. I know the basics like addresses, Start voltage, simple function remapping, etc but unless theres a manual that can tell me what specific value for which CV, I will be lost (but willing to learn!)
 

kbkchooch

"retired" conductor
This might sound too simple to work, but has anyone gotten ahold of Soundtraxx and asked if they were eventually going to upgrade the Tsunami to allow more functions?? If the are planning an upgrade in the next 6-8 months,,,,I personally would just wait for it!
 




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