Installation of a Soundtraxx Tsunami ALCO 251 v12 sound decoder in an Auscision 45

Given that the Auscision 45 class comes with a 21 pin decoder socket for the ESU Loksound v4 decoder this presented me with a problem as I already have seven diesels fitted with Tsunami decoders.

Why was this a problem?

Here are some issues that I had to think about:

• The Loksound v4 momentum factor issue - ESU has moved away from the standard NMRA momentum factor of 0.876 and introduced a factor of 0.25 in the Loksound v4 what this means is that for the same momentum input for acceleration or deceleration the Loksound v4 will only have about 30% the momentum of any other brand decoder. This becomes a real issue when consisting and using the momentum button on a NCE throttle to set the load behind the train. As you can imagine, locomotive consists with a mix of Loksound v4s and other decoders will have trouble as the locomotives will appear to fight each other. The Loksound v4 equipped locomotive(s) will slow down or accelerate faster than the other(s). The momentum can of course be adjusted in each decoder type to match but then that stops the use of the NCE throttle momentum button for more realistic operation.
• There is a Loksound v4 decoder that is available with recorded 45 class sounds that has manual notching whereby a press on the appropriate function key will start the locomotive notching up and there is another key to notch down. While this can give an appearance of prototypical operation it also means that you can drive your locomotive in speed step one up a steep grade with a long train. It can be a bit like playing a musical instrument, you have to think about what you are doing with the diesel motor to match how you are driving. My seven Tsunami equipped diesels have automatic notching and a speed curve set up so that in notch eight the diesel is going at 15 miles per hour. I did this as the NSWGR rated their diesels at what speed could the maximum power be achieved (notch 8) on a 1 in 40 grade. The speeds ranged between 8 to 13 mph so after some experimentation I chose 15 mph as the average of approximately 10 mph was too slow. I also set the Tsunami decoders to notch up/down at 10 speed steps so in 128 step mode you can tell which notch the diesel is in by looking at the speed step (10, 20, 30, etc.). The ruling grade on my Bylong layout is 1 in 40. Incidentally the Loksound v4 decoder does have automatic notching but the notches are spread over the full speed range. I believe that this could be adjusted but the learning curve required is very steep and the available 45 class Loksound v4 is locked so this can't be changed, maybe one day.
• The price of a Loksound v4, enough said.

Since I had an AT1000 Tsunami ALCO v12 already, the choice was made to install it.

I removed the existing board with its 21 pin socket and proceeded to wire up the AT1000.

Edit: I should mention that there is little vertical room for the AT1000 and I had to cut off the two short posts that located the original board at one end. I then glued a piece of 0.005" styrene across the two mounting posts of the original board at each end to insulate the AT1000 from the chassis.

Mostly, everything went well until I found that I couldn't get the headlight/white markers/number boards to light up. The red markers worked and I tested the outputs on the AT1000, the headlight outputs at both ends were good, so a problem with the 45 class. A call was made to Marcus Ammann who quickly sorted me out. It appears that the white wire to the headlight output at each end of the AT1000 is correct but the purple wire has to go to the function common along with the blue wire! The wiring of the Auscision 45 is back to front for DCC, something to do with DCC using a +ve function common instead of the more usual -ve common found elsewhere. Perhaps Auscision need to inform their factory about this anomaly and change it for future models.

Wiring Diagram

 

I wired the front red markers to the FX5 output on the AT1000 and the rear red markers to the FX 6 output.

So what I have is the headlight on F0 (Headlight button on NCE throttle) and the headlight/markers/number boards will turn on at the front or rear depending on the direction of travel, not perfect unfortunately.  The red markers are on/off as required.

This allows me to have the headlight/white markers and number boards on at the front when moving forwards and not have the red markers on at the rear of the locomotive when pulling a train.

Also, when the locomotive is standing in a siding or shunting it can have both front and rear red markers on at the same time as per NSWGR practice.

The headlights, white markers and number boards should all be on separate outputs but this is about the best we can do with the restricted number of outputs on decoders. Although I should add here that the QSI Titan has 10 outputs which almost gets us to the 12 required to handle marker lights etc. prototypically. Unfortunately at the moment they are hard to get.

I used a Soundtraxx 810113 Small Oval Speaker in the 45 class speaker enclosure but I had to cut the sides of the enclosure to fit the speaker (see photo above).

The sound from this speaker is quite good and here it is in the video below along with the same sound decoder and speaker set up in the second 45 class, an AR Kits version. Unfortunately the microphone in my video camera is not that great. I am sure that the Tsunami ALCO 251 v12 doesn't sound as good as the available 45 class Loksound v4 version but it does match my other ALCOs and it doesn't cost as much.

I actually have four Loksound v4s in steam locomotives, I just don't like them for diesels so I am not trying to stop anyone from using the Loksound v4, this is just my implementation for my reasons although I do think that modellers should consider the momentum issue against their existing diesel roster and layout operational ideas.

Approaches have been made to ESU by some well known model railroad identities (as well as Matt Herman of ESU USA) to have a CV added so that the standard NMRA momentum factor can be chosen if required but to no result. We can only hope that ESU will wake up, especially considering their current inroads into the US OEM market.