Digitising LGB 20261 Nicki-Frank-S steam tender loco

idlemarvel

Neither idle nor a marvel
13 Jul 2015
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LGB 2x26x are models of the Henschel HF 110C (0-6-0TT / Cn2t+T). They are quite an accurate model especially compared to the LGB 2x15x model of a Heeresfeld 0-4-0TT discussed in another recent thread. This makes it more of a pity they are over sized compared to more recent LGB efforts, at a scale of approximately 1:19½. The models all have two motors, one in the loco and one in the tender. The prototype could run without a tender as there are water tanks and small coal bunker on the loco (hence the TT/t+T), but I do not know if they ever did in practice. The tender is to provide increased range. Picture of prototype below:

nicki-franks_1.jpg


LGB have produced seven versions to date of this steam loco with tender over many years, with increasing functionality:

2x26x colour number features
20261 blue 798 101 lights smoke
21261 black 99 4642 lights smoke dcc ready
22261 green 99 4642 lights smoke dcc ready
23262 black 99 4641 lights smoke dcc fitted sound
24265 black 99 4643 lights smoke dcc fitted sound
24266 blue 99 4642 lights smoke dcc fitted sound
24267 black 99 4642 lights smoke dcc fitted synchronised sound
(Not sure why there was never a 2026 / 20260 model.)

This posting will only be of interest to those with one of the first three models. I have just acquired one of the early models, 20261 (blue livery), which is not DCC ready in theory, although the motor blocks have 4 pins (green/gn, brown/br, white/ws and yellow/ge) which is as DCC ready as most early LGB locos. In this analogue version of the loco, the white and yellow pins are hard wired together with a white cable. (For those not familiar with LGB wiring colour convention, white and brown are +/- from the track, yellow and green are +/- to the motor.)

The three wires (brown, green, white) from the tender motor block pass to the loco using a flexible four wire plug. This is to allow the power to the lights and motor of the tender to be controlled by the 3-way switch in the cab of the loco (0=off, 1=lights, 2=lights+motor). The fourth wire in the flexible plug is a return from the loco for the lights only setting. There is a small circuit board in the tender which holds a diode to make the lighting directional, the two lower rear lights, two pin plugs for the upper tender rear light (to make removing the top of the tender easier), and the multi-purpose socket at the back of the tender. In this model the multi-purpose socket is the old style two separate round pin plugs. The wiring loom from the tender is shown below:

IMG_20180326_192431.jpg

There is a similar arrangement in the loco. The yellow and white are hard wired together as in the tender. The three wires from the motor block (brown, green, white) go to the 3-way switch. There is a larger circuit board with 10 vertical pins onto which are connected the cab light, the three front lights and the smoke generator. Legend has it that the circuit board also reduces the voltage slightly to the tender motor to prevent the tender pushing the loco but I have not been able to confirm that.

IMG_20180326_194821.jpg

The end result is that you have a loco with two motors, 10 powered wheels and 14 pickups just over half a metre long. I imagine the pulling power is fairly impressive but I will never know from my tiny layout.

So that is the starting point for digitisation. My requirements are to DCC enable the motor control, lights (directional and cab), multi-purpose socket, and I would like to add sound, firebox light and if possible automatic uncoupler in the tender. Finally, I would like the ability to run the loco without the tender. I should add that I already have a SUSI sound module so I do not need a combined motor and sound decoder.

With a conventional one body two motor loco I would just get a Massoth XL or similar two-motor decoder, but in this case the motors and lights are in two separate pieces, so there could be many wires between the loco and the tender:

2 for track (incoming from tender)
2 for motor (outgoing to tender)
2 for lights
2 for multifunction socket (you could take this straight from track but I want to make it switchable)
3 for uncoupler (you could share a common return with the lights)

So that is a minimum of ten, or another six on top of the existing four wire connection. You could argue that you do not need the track connection but then you would be relying on the loco pickups only. You could also reduce this if you put the decoder in the tender but you would still need more than four which means messing with the existing connection.

Another option would be to install two single motor decoders, one in the loco and one in the tender. In theory you would then not need any wires between the locos, they could be completely independent, but as stated above you would want to share the power pickups across both decoders if possible, so two of the existing four wire connection would be used to share the track power.

A third option would be to use a two-motor decoder in the loco, and to reduce the number of wires, have a function-only decoder in the tender. That way you could use the existing four wire connection for the track and motor connections, but all the tender lights and uncoupler features would be driven by the function-only decoder, which once programmed would have the same address as the two-motor decoder.

The pros and cons of each approach are summarised below:

table.JPG

It would appear that there is no clear “best” solution; it is a balance of cost and convenience. As the cost of a Massoth L is almost as much as an XL these days I have gone for the third option. I will post progress
 
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Zerogee

Clencher's Bogleman
25 Oct 2009
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I'll be following this thread with interest, Dave - I have an early green/black Frank S to do at some point..... my other two came to me ready-chipped, a recent (but pre-MFX) black one with factory DCC and sound, and a first production blue Nicki & Frank which came chipped by the seller (a fellow member on here) who went the two-decoder route with the loco and tender completely independant of each other - I believe there is an LS or XLS in the tender and either an L or XL in the loco, both independantly programmed by trial-and-error to equalise the speeds, at least that's what I was told when I bought it.

Jon.
 

stockers

Trains, aircraft, models, walking, beer, travel
24 Oct 2009
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Good choice on the decoder set up. Two decoders has never given a 'best' result and now with back EMF (speed control) they may fight each other and create a very jerky movement. Putting a function controller in is a neat idea - I just put my front lights on the motor with a diode. I did link the power from all pick ups to the decoder as well as back to both motors using the four wires available.. But I wasn't using an auto uncoupler. My decoder is in the tender.
 
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Zerogee

Clencher's Bogleman
25 Oct 2009
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Good choice on the decoder set up. Two decoders has never given a 'best' result and now with back EMF (speed control) they may fight each other and create a very jerky movement. Putting a function controller in is a neat idea - I just put my front lights on the motor with a diode. I did link the power from all pick ups to the decoder as well as back to all the wheels. But I wasn't using an auto uncoupler. My decoder is in the tender.

While I agree in theory, and will most likely use the same setup as you when I get round to doing my green one, I must say that my two-decoder blue one runs very well.....

Jon.
 

pugwash

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Physical problem: if you want to use the loco without the tender how and where will you fit an LGB coupling? The fitting between the two is a pin in a hole and covered by a footplate.
 

PhilP

G Scale, 7/8th's, Electronics
5 Jun 2013
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Your choices would, of course, be different if you did not want to run the loco and tender separately..

I guess you may want to run the tender with a different loco?
 

Zerogee

Clencher's Bogleman
25 Oct 2009
17,126
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North Essex
Physical problem: if you want to use the loco without the tender how and where will you fit an LGB coupling? The fitting between the two is a pin in a hole and covered by a footplate.

Depending on the relative heights, of course, you might be able to bodge it by simply dropping the pin on the loco connection into the loop on the leading wagon/coach.....?
Then again, that might be rather too closely coupled for comfort on curves?

Jon.
 

mike

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I have 2 with a xls in the tender...
I have used the 4 wire connected the loco and tender for pickup purposes..and motor.. I recycled a old Mts2 as a smoke/lighting only...both decoda have same adress...
The 3rd is mfx
 
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idlemarvel

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Physical problem: if you want to use the loco without the tender how and where will you fit an LGB coupling? The fitting between the two is a pin in a hole and covered by a footplate.
Good point pugwash pugwash I haven't thought that through yet. I was wondering if I could just replace the special hook with a standard one, and the footplate folds up with the doors closed when running without a tender (I guess). As I said I don't know if they ever ran without a tender, but I thought it would be nice to have the option.
 

Zerogee

Clencher's Bogleman
25 Oct 2009
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I have 2 with a xls in the tender...
I have used the 4 wire connected the loco and tender for pickup purposes..and motor.. I recycled a old Mts2 as a smoke/lighting only...both decoda have same adress...
The 3rd is mfx

With your two single-decoder XLS examples, Mike, have you ever noticed any sort of speed differential problems between loco and tender when both are being driven from the same decoder output?

For mine, I'm thinking XLS in the tender, and a six-way connector between loco and tender (2 x power, 2 x motor, 2 x lighting - probably won't bother with connecting the smoke.....). I have some nice little 6-way plug and socket sets, pre-wired, that came from evilBay.

Jon.
 

mike

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Yes Jon. But think about it..
Loco is 6 wheels and valve gear ..
Tender is 4...there has to be more friction to over come on the loco than the tender..and that's the only thing I can think of.. if you can live with no motor in the tender (mates got 1) it's far better
 
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mike

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Its a xls jon. It dose both motors..the 1 in the loco dose the front lights and smoke only
 

idlemarvel

Neither idle nor a marvel
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Does anyone have a DCC fitted model, either LGB or Maerklin regime? What is their approach, do they provide one two-motor decoder or two one-motor decoders?
Thanks, Dave
 

Zerogee

Clencher's Bogleman
25 Oct 2009
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Yes Jon. But think about it..
Loco is 6 wheels and valve gear ..
Tender is 4...there has to be more friction to over come on the loco than the tender..and that's the only thing I can think of.. if you can live with no motor in the tender (mates got 1) it's far better

Sorry Mike, just to be 100% clear on this - with a single XLS decoder running both motors, you HAVE had speed differential problems with yours? With the tender running faster, trying to push the loco along?
Is it enough to be a noticeable problem under normal running conditions, for example do you get wheelspin from the tender and/or does it appear to be putting undue stress on motors and gearboxes?

Jon.
 
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Zerogee

Clencher's Bogleman
25 Oct 2009
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Does anyone have a DCC fitted model, either LGB or Maerklin regime? What is their approach, do they provide one two-motor decoder or two one-motor decoders?
Thanks, Dave


My black version (which I think is early Marklin era, still with LGB decoder/sound, definitely pre-MFX) has, I THINK, only one decoder - but I can't be certain as I've never opened it up...... don't know if it has any clever extra gubbins to equalise the speeds......
Anyone else opened a factory-DCC one of these and had a good poke around inside?

Jon.
 

AustrianNG

Director of my railway
16 Sep 2015
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My Black version is the same as yours Jon.
I suspect it has one decoder - I have never known LGB fit two on a factory issue loco.

My green one has a Zimo decoder in the tender for both motors and a Dietz sound module, also in the tender.
 

dutchelm

Registered
24 Oct 2009
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The factory fitted MTS loco has a large onboard decoder driving both motors, hence the 2 sets of plugs & sockets between the loco & tender.

When I fitted MTS to my early blue one I bought a spare set of PCBs from a later version. The owner only wanted the chassis & was selling off the remains. I just swapped the boards & pluged in 2 x 55021 decoders. Never had any problems with different speeds.
 

dutchelm

Registered
24 Oct 2009
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I should have added that there were a batch of black locos with MTS fitted. These were used to rid LGB of the old 55020 decoders as they had 2 of these on the "plug in" boards.
 
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idlemarvel

Neither idle nor a marvel
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Fitting the automatic uncoupler in the tender was tricky and required some serious surgery to the tender motor block.

IMG_20180326_192510.jpg

Luckily there were no moving parts in the way!

IMG_20180326_193000.jpg

After some careful work with a razor saw the cut-out looked like this:

IMG_20180328_194559.jpg

The cut-out removed one of the screw holes but there are still 3 screws to hold the motor block "lid" in place. The automatic uncoupler then fitted quite nicely, with the lead emerging from the top of the motor block.

IMG_20180328_201843.jpg

I wired up the function decoder to the track power and connected the automatic uncoupler to the function decoder DEC+, A1 and DEC- wires. No configuration of the function decoder was required except to change the function key (F9).

I connected the tender lights to A2 and multifunction output to A3. I set A2 to operate on F0 only when going backwards, and A3 to operate on F0 regardless of direction. The function decoder is quite flexible in this regard; you can set each function output to operate regardless of direction, backwards or forwards only, moving backwards or forwards, or stationary with direction set to backwards or forwards. This is called the Condition setting.

Now waiting for XL decoder to arrive.
 
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mike

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Yes it can happen jon