Train Set Locomotive, what can I do?

[DieCastoms]

After such wonderful feedback (which I need to reply to) to my post in the N Scale forum, I thought I would try my luck with another issue.

I was recently given an HO scale trainset quality GP40-2 with a Digitrax 4 function decoder (DH140). 

First of all, the loco does run and I have been using it to experiment with DCC settings, since my other equipped loco runs so smoothly that the settings don't make obvious differences.  On 28 speed steps with factory settings in the Digitrax, the loco would not move until speed step 8.  I adjusted the start voltage and it now moves at step one, however it is a very obvious boom-bust cycle because of the cheap 3 pole motor and lack of flywheel.  Short of tossing the loco and getting a better one, what can be done about the surging?

I also have the option of swapping the two decoders I have.  The decoder in my Roundhouse 2-6-0 is a TCS T1 which would have Dither that might help (don't know much about Dither yet).  The drawback here is, the T1 has only two functions, and the DH140 has 4.  I have no use for more functions in the steamer and I WANT more in the diesel..

The loco currently only has reversing headlights and since it has a 4 function and isn't a prize winning loco, I would like to use it to experiment with adding other lights to the shell.  I would like some suggestions on what lights I could add.  I have already boxed in the cab ceiling so that the light there only shines through the headlights and number boards, so the cab is dark.  I do not think I could add ditch lights, not to mention if I did add them I would want to put them on actual ditchlight functions and that takes two functions, doesn't it?

I had more for this post when I began typing it but now I can't think of anything else to add... so I am posting it as is before my browser decides to crap it out...

Mike, from DieCastoms

[Guilford Guy]

Not all ditch lights alternate. On Pan Am none of them do, they are turned on steady when approaching a grade crossing, so you could have them installed and have both wired to the same function. Some locos had strobes on the roof of the unit, and this would be possible with the remaining functions. Aside from cab lighting there isn't that much else you can do, although step lighting would be a cool effect especially at night.

[DieCastoms]

Ok so how about this:

• 1 Directional Headlight, Front (1 bulb), diode connected to number-boards (1 bulb)
• 2 Directional Headlight, Rear (1 bulb, maybe 2), diode connected to number-boards (same bulb as above)
• 3 Mars Light (1 bulb)
• 4 Interior Light (1 bulb)

The diodes mentioned in Function 1 and Function 2 are connected to a single light bulb for the number-boards, so that when EITHER headlight is on, the number-boards will be lit as well.  This assures that the number boards will be lit regardless of other functions as loon as the F0 is on, and frees up the function that will become the mars light.

I will soon be working on an SW9 (LifeLike, N Scale) which will have the following:

• 1 Directional Headlight, Front (1 bulb)
• 2 Directional Headlight, Rear (1 bulb, maybe 2)
• 3 roof beacon (1 bulb)
• 4 Interior Light (1 bulb)

If i can find an acceptable flashing LED, I may use the diodes to get power from the directional lighting to run the roof beacon, and use that freed-up function to add controlable ditch lights.

These two locos are a case of "how much can I manage to do on these two locos that might be useful on future builds?" so overboard is ok

Guilford Guy:
Thank you for pointing that out to me.  I do not know much at all about prototypical light functions or locations.  I was told that the ditch lights would flash alternately when the horn was sounded, if ditch-light CVs were used.

Mike from DieCastoms

[Jim Banner]

If you want to learn even more about decoders, invest in a newer one with Back EMF motor control.  This is a lot like cruise control in your car, and can even out a lot of the jumpy starts.  As you are in N-scale, a Digitrax DZ143 would be a good choice.  It has BEMF control (Digitrax calls it "Scaleable Speed Stabilization") as well as being hefty enough for many H0-scale applications but small enough to fit many Z-scale locomotives.  It also has 4 function outputs.  If you like it in the H0 diesel, you could leave it there.  If not, you can still use it in an N-scale locomotive.

For just trying out BEMF control, you could swap the DH140 with the T1.  TCS also refers to this decoder as having "auto-adjusting BEMF" which to me means I cannot adjust it for my best fit to my locomotive.  TCS BEMF is explained at this link: 
http://www.tcsdcc.com/Customer_Content/Technical_Info/Tech_Manuals/BEMF.pdf

Jim

[DieCastoms]

Jim, unfortunately "investing" in anything right now is not much of an option right now.  All my equipment that I currently own has come in the form of a gift or a trade with other hobbyists.

Also, I am only running HO scale.  The N Scale equipment I have been talking about is part of a trade.  I am doing decoder installs in several N scale locomotives in exchange for all this person's old HO scale stuff..  The GP40-2 that I have been talking about is part of this deal as well as 15 eztrack turnouts, 4 or 5 circles of track, and a bunch of straights, as well as a couple diamond crossings..

As far as BEMF is concerned, the TCS T1 has it and I have experimented with it.  The T1 will start and stop my roundhouse 2-6-0 on a 10% grade without slipping, and it will still begin to move at the first or second speed step, on 128 steps.

I was under the impression that, at low speeds and starts, the Dithering feature of the TCS decoders was more useful than the BEMF.

[Jim Banner]

I was under the impression that, at low speeds and starts, the Dithering feature of the TCS decoders was more useful than the BEMF.

Depending on the locomotive, that may well be true.  I have not tried dither in a reluctant locomotive, although I will admit to dithering over them myself.

Jim