I hope everyone had a great Christmas. Danielle and myself had a good time however are happy to be back home after a fair amount of travelling.
Before Christmas I embarked on another XPT recording session. Blacktown railway station was a real eye opener. Never before have I seen so many ankle trackers in one place. Glad to be alive still!
I now have better XPT horn recordings. Still, these recordings have been by far the most challenging recordings to edit. For the XPT project, if the applicable function button is held the corresponding horn (there are three horns) will play a full 4 second burst and fall silent. If you only want a short horn burst you simply deselect the function quicker. No function room on this project for three separate long and short horns.
As the XPT project is really my first full blown attempt at a diesel project, I thought I would try and modify how the general diesel sound flow works. While I am sure there are third party sound developers out there that have already paved this path, I personally have not come across anything that suited me.
What didn’t suit me:
Generally when you accelerate an ESU diesel project, the model accelerates at a set momentum rate and the sound flow increases as per set thresholds. These thresholds can comprise of multiple factors. This all works well.
It was decelerating that bugged me a little. When a locomotive comes up to speed and no more power is required, say cresting a hill, accelerating up to track speed, drifting down a hill, the throttle is generally shut off an amount that suits the conditions. This could mean the throttle is simply backed off one or two notches or placed back into one notch (I won’t say placed into idle here as I will have a flurry of people tell me how a diesel locomotive should be driven). What I am trying to say here is that the throttle directly effects the prime mover engine revs. Track speed is a product of environmental and power requirement factors.
When it comes to models fitted with sound, generally the locomotive speed needs to be decreased so the sound flow transitions into lower notches. This in a way creates the sense that the locomotive is being braked by the throttle.
ESU have ways of detaching the engine sound to driving speed in the form of manual notching. This however can be a little cumbersome and I really wanted a method of doing all of this by throttle manipulation rather than function button playing.
Some may not agree with this thinking.
The XPT project:
Here is another badly filmed movie! It's a shame that the function buttons did not show up better in the video. You can just make out the selected function button by the border that appears around the box.
My XPT project now has the ability to let you travel at track speed and ‘coast’ with the engine in any notch, all selected with the throttle.
If accelerated up to speed step (SS) 22 (I always use 28 speed steps), the XPT engine will accelerate up to throttle notch 5 (max throttle setting for an XPT) and track speed will build as per momentum settings. I have used speed step 20 as one of the thresholds for the diesel engine sound being at maximum revs. This was to help simulate a hard working XPT while traveling at two thirds max track speed.
Once the XPT is up to speed (SS 22) and the throttle is decreased down one SS to 21, the XPT engine will progressively come back to notch 1. As the throttle is still selected at SS 21 the models track speed remains relatively constant. The XPT will maintain notch one and track speed 21 for good if no change is made.
Once the engine sound has settled to notch 1, by increasing the throttle one SS, back to 22 the engine sound will progress back up to five notch.
If for instance we are travelling at SS 22 again and we want to decrease the throttle to four notch without effecting track speed, you simply move the throttle to SS21, listen for the decrease in engine sound and then reselect SS22 and the XPT will remain in four notch. If three notch is then required move the throttle to SS21 again, listen for a decrease in engine speed and then reselect SS22 on the throttle. The engine sound will then remain in three notch however track speed is still set at SS22.
Once again if the throttle is increased one SS, to SS23 the engine will once again move to notch five.
Another feature is the incorporation of a function operated brake. When the braking function is used, the XPT will come to a stop faster. Braking times are adjustable by changes in momentum setting. When the brake is applied and released brake pipe sounds are heard. When the loco is stopped with the brake function, braking squeal is played.
For me this has added a little bit of fun to the project and once being operated on a layout, will make it quite a challenge to stop at a platform. Just like the real one.
As in my last blog posting, the project still allows for one XP power car to operate in service mode (engine speed remains in two notch). This is function button selectable and applies to the trailing power car.
I am happy with this project for use in the XPT. I think a diesel freight locomotive, for most prototypical realism would need a similar throttle notching set up for when increasing engine speed also. Perhaps one day.
For the XPT I used two ESU V4 21 pin decoders, two ESU Power Packs and two Zimo LS 10 x15 sugar cube speakers.
The XPT install was one of the most straightforward I have carried out. The strobes, headlight, white marker lights (ditch lights) and red markers are all wired individually. The blue and green wires are both commons for lighting (markers and ditch lights). These commons run through two of the switches under the fuel tanks. The grey wire is connected to the red markers and the yellow wire is connected to both white markers and ditch lights. You may be confused here - I was. Weirdly if the blue wire (+) and the yellow wire are powered the white markers light up. If the green wire (+) and the yellow wire is powered the ditch lights illuminate. I found the lower lighting board impossible to open up for fear of breaking it. This means, to separate the white markers from the ditch lights will require the green common wire to be isolated. This will be possible by using an amplifier circuit switching the positive side, utilising one of the decoder logic only outputs.
The headlights and strobes are connected through a 4 pin connector. The lighting connections are already made to the 21 pin plug. All that is required is to map the functions correctly.
Pin 15 - Aux 1  = Strobe - These have been mapped to flash when the horn is blown. May have to fix up the cabin disco. I didn't notice all the flashing in the window until I watched the video!
Pin 14 - Aux 2  = White Markers – This requires soldering onto plug (yellow wire)
Pin 7 - Rear light output = Head light
Pin 8 - Front light output = Red Markers
I also swapped the motor wires around as I think they were wired backwards. I am using the same address for both loco units and have simply used the ‘reverse direction’ option on the trailing unit. This allows all the direction features to operate properly.
That’s About That:
I am yet to run my XPT set on a layout but so far running on the rollers looks favourable.
I need to thank Dave for being so helpful in allowing me to record the XPT. Much appreciated and a copy of the file is all yours if you want it.
Now to get on and weather the set. This could be interesting!
Thanks for looking. Have a great New Years!