Car & Locomotive svc and DCC...

I'd be curious what your "advisor's" reason/reasons for making that statement is?

Simon

Not familiar with CLS locos, but the only difficulties in adding DCC would be an uninsulated motor mount grounded to the frame or a non-DC compatible motor. Are either of these the case?

Jim

Simon,

He told me that the gearing and engines didn't mesh well with DCC; I have no experience, hence I am asking the question.     I own several and would like to upgrade them.    By all means contact me thru personal email if you can help.

Thank you!

I did "temporary" installs in C&LS RS11s, RSD12s, and an RS32. In those I used NCE 408 motor/lighting decoders and the discontinued Soundtraxx DSX sound decoders. I wouldn't say that they were really any harder than other Overland brass diesels. That said, these were temporary installs because they were done quickly to put unpainted units into service for operating sessions. All the units are now packed away waiting for service in the back and paint shops prior to the start of operations on a friend's new and bigger layout.

There are a few things to know:

1. Many diesel units were delivered with wheels slightly under gage. Henry designed and machined a nice tool to spread the wheels farther apart without dismantling the trucks (I watched him use it on a couple of my locomotives as I cradled them in my hands.) This isn't a DCC issue but you may want to check wheel gage. In DCC shorting the back of a wheel against the point of a DCC-unfriendly turnout can cause greater hiccups than with DC power.

2. The light fixtures in his diesels are fully boxed-in from the rear. This can make installing bulbs a bit trickier, but nothing that can't be solved with a die grinder a/k/a rotary tool if need be. The temporary install used simple 12 volt leaded bulbs. I can elaborate more if you wish.

3. Henry used a 24 volt Pittman motor (he removed the Pittman label) and if I recall only a 6:1 or similarly short gear ratio in the ball-bearing gear towers. As he told me, he wanted his trains to "feel the grade." And that was an understatement! The 408 does not have back-EMF and boy did they ever feel 3% grades! My engines almost, but not quite, free-wheeled downgrade on the point of heavy coal trains. 

If you want opinions and observations about available O-scale decoders as they are suitable in C&LS diesels, that is a different subject and one best addressed in a different discussion.

Hope this proves helpful.

Dear Bob,

I would be most grateful for your input on appropriate decoders for the following CLS models:

RS-11 (high and low hood versions), RSD-12 and  Trainmaster units

Thank you in advance,

Brad

Brad -

At the moment I can't say that I have found an entirely satisfactory solution.

Decoders without back-EMF, such as the NCE D408SR (my standard decoder), did not achieve satisfactory smooth starts in my C&LS engines. That appeared to be caused by the locomotive's unusual gear ratio. The locomotive would not move without opening the throttle quite far, but by then the throttle was already set for surprisingly fast running. So a good start required "blipping" the throttle to try to kick the locomotive free. Current 408 decoders have optional low-speed kick pulses much like the venerable TAT-4 DC throttle but even these were not quite up to the task. This said, I plan to continue using the 408 in my non-C&LS locomotives as I am otherwise quite satisfied. It is a robust and thin design with a built-in heat sink, and easy to fit in most locomotives.

These days I would choose a decoder with back-EMF as it can regulate speed much more quickly and precisely than we can. A second factor might be sound. 

The NCE web site shows a D408E-SR back-EMF decoder, but after many, many years it is still "not available."

I tried a Digitrax decoder but was never able to adjust the control CVs to get smooth running. It tended to buck and sounded like a hit-or-miss gas engine. I was also curious why the decoders defaults turn off back-EMF. Perhaps I discovered one reason. Perhaps others will be more successful in tuning the CVs. I gave up.

The Lenz back-EMF decoders I've operated in other locomotives always provided outstanding low-speed operation. However, in my HO days I had troubles consisting Lenz decoders with back-EMF turned on. The speed regulation was so precise that two otherwise identical locomotives would fight each other for dominance. I can't say if that would be an issue with their latest O-scale offering or not. We never consisted two Lenz-equipped locomotives on David's old layout. Lenz decoders also tend to be taller, but the green screw terminals could be unsoldered if need-be.

I'm personally not a fan of QSI prime mover sounds so I have no real experience with them. I did watch a friend's Atlas F-unit start run very smoothly on DC despite the notorious twin-motor "china drive." Nor can I say if there is room to fit the decoders.

Some folks have tried using HO Tsunamis in a few O-scale locomotives. I haven't measured the current draw on my C&LS engines so I can't recommend trying that unless you don't mind risking a decoder. That said, since it uses a 24 volt motor the stall current should be about half that of the usual 12 volt 8xxx Pittman (about 8 amps for the P&D 12 volt drives.) The modified Tsunami from ProtoCraft is intriguing but I haven't (yet) tried one.

I have absolutely no experience with ESU decoders. Some modelers in HO have given good reports.

Soundtraxx seems unlikely to ever produce an O-scale decoder (the company representatives appear to be annoyed whenever I ask.) I have started my own Tsunami booster design but that project has been put on the back-burner. When it comes time to paint my C&LS engines, I will probably try this first, and perhaps a ProtoCraft modified decoder.

There should be plenty of room in the long hood of the RS11 and RSD12 for at least a motor decoder. I've never seen the inside of the Trainmaster, but the long hood is quite wide. Internal space at the radiator end may be consumed with the operating fans and control board. A Tsunami 750 should easily fit in any of the short hoods.

Sorry I could not give a definitive answer. Hope this helps.

Bob,

Thank you, this is helpful.    Sound is not a primary feature for me in these engines; speed and control are the more relevent issues.     Would this change what options you pursue?

Thanks,

Brad

Brad -

Without sound it might be worth trying the Digitrax DG583S. It should barely fit in the RS11 and RSD12 but I can't be sure in the Trainmaster (maybe above the motor?) The decoder is fairly wide, at 1.4 inches, so it probably would need to sit at an angle or vertically at the end of the long hood. The reason I mention this is that it is newer than the Digitrax decoder I previously tried, and I see in the documentation that back-EMF now defaults to on (but with very mild compensation, and only if not operating in consist.) The latter may suggest a design improvement to the back-EMF algorithms. I'm curious and may eventually buy one to see how well it can be made to work.

Bob,

Thanks again---I will also reach Norm at Protocraft and seek his input---

Care to post images of your CLS models?

Brad -

Two more things I remembered:

1. On RSD12s I added Kadee insulating washers on the insulated side of the axles. These stopped intermittent short circuits between the wheel faces and the sideframes.

2. If you need to disassemble a unit for painting, you may wonder how to get one of the handrails off of one of the stanchions. Look closely at the back side of the stanchion where it grabs the handrail. You will see that it is actually split in the back, and can be very carefully bent open to allow the handrail to fall out.

As for photos, very few were ever taken because the units are still unpainted brass. Here is a grab shot from an operating session on David's old layout. Two RSD12s and two RS11s are on the point of a 42 car coal drag. Each hopper weighed 2.2 pounds and was filled with a live load. 

Bob,

Great shot---and I cannot thank you enough for your help!

Brad -

I just tested the locked-rotor stall current on a C&LS RS36. Surprisingly, it was only 1.1 amps at 12.0 volts. This means that many HO decoders should be suitable. The smaller size would make them easier to install. 

Learn something new every day!

This setup NCE decoder and Soundtraxx DSX in a CL&S diesel was done by Bob Jones years ago.…There is plenty of room under the hood and I might try a QSI titan to eliminate the 2-decoder system….Bob built the speaker box and today we have hi bass speakers from QSI that might be better for sound….I have not done any measurements for the titan but I think it will fit. Personally, I think a one board system is the way to go…

Dennis 

Nice looking install, Dennis. I like the way that a thin decoder such as a the 408 can mount between the cab floor and frame. Wish we could still buy the smaller DSX sound-only decoders.

I just did a test install of a Tsunami single decoder in an RS-36 and was able to fit a 1.5 inch high-bass speaker sitting diagonally under the radiator fan. At 1.1 amps the stall current is just a hair past the 1 amp rating. The decoder is mounted under the cab with its heat sink against the frame for better cooling. The drawing below is an end-view. The speaker aims at the side of the locomotive. The red line was an estimate of the minimum clearance needed for the rear truck gear tower. By the way, ordinary Elmer's rubber cement is wonderful for sealing leaks in a styrene enclosure, and to tie-down wires inside the cabinet so they can't rattle against anything.



Setting up back-EMF was quite tricky and I still can't sufficiently lower the minimum speed. On the other hand, "jackrabbit" starts are gone, at least on my test track. It will be a few more days before I can test it with a train and grades on a layout.

Today I tested a Tsunami TSU-1000 driving the motor in a C&LS RS-36 on the A&O layout. Measured on the test track, wheel slip drew less than 3/4 amp continuous and 1.1 amp rotor stall current so it might be within the decoder's actual capabillities. The TSU1000 documentation claims a 1 amp stall current, so this is 10% outside the manufacturer's published ratings. Your mileage may vary.

Test results
The decoder never thermally shut-down but did "run away" a couple of times, operating at full speed after encountering dirty track (the layout is currently a dusty construction zone.) And yes, DC operation was disabled and confirmed later by reading-back CV29 on the programming track (Alternate Power Source, bit 2 in CV29=0.) There was no response to the throttle. Tipping the locomotive to induce a decoder reset restored proper operation, as if somehow the decoder suddenly decided to ignore CV29 and switch to DC power anyway.

I did not have time to explore whether setting the watchdog timer, CV11 (Packet Time Out Value) would halt the engine before the decoder lost its mind on dirty track. If so, would it gracefully recover or just drag wheels in a shutdown state? Not sure.

I used a motor setup procedure posted on the Tony's Train web site titled "Soundtraxx Low Speed Tuning." On decoder reset settings the minimum speed was insanely fast at perhaps 15 SMPH. Although I eventually did get an almost-satisfactory minimum speed, when the locomotive encountered a heavy load upgrade it buzzed like beehive at low speed, and drowned out the speaker by the time wheel slip occurred. Several cars coupled to it also vibrated to the point of "singing in harmony through vibrating couplers."

The good news was that the locomotive did require far more throttle to run upgrade than down, so the prime mover sounds were (when not drowned out by the motor drive) pleasantly more prototypical than I've ever heard on any layout. Note: Considerable momentum in CV3 and CV4 also helped, but did not influence the greater throttle required to pull maximum tonnage upgrade.

The sound reminded me of the GP7 I ran at the Tennessee Valley when climbing the steep hill adjacent to the station below NMRA HQ. Run 3 (or 4?) was needed just to get the light locomotive up that grade. That too was true with the Tsunami + C&LS drive even after the momentum effects wore off. The model truly felt the effects of the grade, just as Henry wanted them to. (Source: private conversation with Henry Butmann during his visit to David's original O-scale layout.)

I'll keep on the case and report any new findings. But for now, my personal experience is a mixed bag.

Upon further reflection and skimming through the Tsunami Technical Reference, it appears that the "runaways" might have been normal operation. CV118, Motor Recovery Speed, sets the percentage of current throttle speed step the decoder jumps to immediately after a momentary power loss. The default is 60%. My decoder was programmed with a lot of momentum in CVs 3 and 4. During one runaway event I do remember that the unit hesitated then took off, then I turned the throttle down from full to zero. It may have actually jumped to the default 60% of current throttle and stopping momentum prevented regaining immediate control.

If this was the issue, setting CV 118 to a value of 128 would set the recovery speed to 0, or perhaps 141 to a relatively safer 10%. Or, the option button on our NCE CAB04PR throttles could be reprogrammed as an emergency stop.

Time for more experiments!

DC mode is CV29, bit 2, known as "Alternate Power Source", which as noted was confirmed to be turned off.

Ya, that's the one    I use JMRI so I don't know all the CV numbers and bits etc...

Further tuning and testing on the layout proved that the "runaway" problem on dirty track was indeed due to running with a lot of momentum and without proper adjustment of CV 118, motor recovery speed. Unfortunately, that particular decoder is so old that Soundtraxx had not yet added CV 118, so when power is restored the locomotive ignores momentum and jumps to whatever speed is set on the throttle.

I eventually achieved smooth and slow operation but it required changing the mysterious CVs 113 and 114 and cutting the top speed in half using the forward and reverse trim CVs. We want to restrict top speed anyway as the A&O isn't a racetrack. At wheel slip, and full throttle (restricted), the locomotive draws 0.56 A according to an RRAmpMeter from Tony's. At no time while lugging cuts of cars upgrade at the verge of wheel slip did the decoder shut down from an overheat.

More details including specific CV settings can be found in the A&O forums.

Hope this helps.