# Conrail SD-40 TMCC Conversion



## gunrunnerjohn (Nov 10, 2010)

Well, here it goes, this is the graphic edition of converting an engine from a mechanical E-Unit to TMCC control.

First, the intended victim before the surgery.













Open him up and we find a traditional E-Unit and Lionel's wimpy electronic horn.











Strip all the old stuff off, but I left the speaker for a future sound upgrade.











Start on the trucks installing the electrocouplers.












One down, and one to go, the coupler installation is probably the hardest of all the tasks.











The truck is back on, route the wire up the only available place. Since it was in what appeared to be a somewhat risky place, I put heat-shrink on where it might chafe, then clamped it to the motor with the brushplate screw.











Fast forward to after installing the other electocoupler and replacing the mounting springs and nuts for the trucks. If anyone has a foolproof way of getting the tin nuts off without wrecking them, I'm all ears! Fortunately, I had the foresight to order some of these and have them around before the project began. 











Time to mount the A/C Commander controller onto the chassis.












Next, we have to install the filter caps for each of the motors.












Following the simple instructions, connect all the loose wires to the A/C Commander board using the screw terminals and the mini-plugs for the electrocouplers.












Stick a temporary antenna on it, time for a track test.












By George, I think we have it. Wakes up and runs like a champ using the Legacy controller!












After the track test, I tied all the wires with a couple of cable ties. Missed that picture when I was working. Stick the case back on it, after connecting the lights and antenna, and another track test, SUCCESS! 











As with any good project, there are always a few spare parts left after you finish. 












There you have it, a TMCC equipped locomotive from an old mechanical operation model.  Looks just like it did before, but now it'll run conventional or command control.

It doesn't have sound, that's a $100 option, so I'm saving my pennies. That's a separate board that simply plugs into the board and the speaker, so it's an easy install, just a hard purchase.


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## tjcruiser (Jan 10, 2010)

John,

Great idea for a thread. Nice stepwise photos of the open heart surgery! Clear presentation.

This modern electronics stuff is way over my head, and I'm not even sure what I'm asking, but ... Can you identify the specific part number (or whatever) of that TMCC board so that others here will know specifically what you installed?

Thanks,

TJ


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## rayins (Dec 31, 2010)

gunrunnerjohn said:


> Well, here it goes, this is the graphic edition of converting an engine from a mechanical E-Unit to TMCC control.
> 
> First, the intended victim before the surgery.
> 
> ...


TMCC control, a nice clean looking install, even looks like less spaghetti


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## gunrunnerjohn (Nov 10, 2010)

tjcruiser said:


> John,
> 
> Great idea for a thread. Nice stepwise photos of the open heart surgery! Clear presentation.
> 
> ...


Did you miss the link to the A/C Commander, the exact part I used?


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## servoguy (Jul 10, 2010)

John, It looks like the caps on the brushes are polarized caps. I am curious how polarized caps can be used in this application. Do the caps have a + or - terminal? Usually caps like this have a row of minus signs down one side which designates the negative terminal. 

BB


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## gunrunnerjohn (Nov 10, 2010)

Actually, they're 50V 1uf non-polarized caps. They do look just like standard electrolytic caps, but they're not.


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## servoguy (Jul 10, 2010)

John,
Just a thought here about the speaker. If you can make a baffle to put around the speaker it will sound much better. Without a baffle, the low frequency sound waves go around the speaker and are much attenuated. If you brought the baffle out to the fuel tanks on the side and made it as long as possible, it should improve the low frequency output of the speaker considerably.

BB


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## gunrunnerjohn (Nov 10, 2010)

The speaker is inside the fuel tank on the completed installation. That was the factory location. Are you talking about a cylinder surrounding it like the installations I see with some factory horns? I could do that inside the fuel tank.


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## servoguy (Jul 10, 2010)

I was thinking of a flat piece of stiff cardboard that would be glued to the speaker and extend sideways to almost touch the fuel tanks and extend long ways to almost touch the trucks. A tube around the speaker might work as well. It would need to touch the bottom of the loco frame and have a small hole (1/4" ?) somewhere. This would make it a "bass reflex" speaker. 

BB


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## gunrunnerjohn (Nov 10, 2010)

That would be a lot easier, the fuel tank has a smaller opening, you have to angle it to get it over the speaker.

Before I put the sound board in, I'll consider the cylinder, it's the easiest.


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## servoguy (Jul 10, 2010)

Let us know how it works out.
BB


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## gunrunnerjohn (Nov 10, 2010)

I haven't sprung for the $100 RailSounds kit yet, still thinking if this engine needs sounds.


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## T-Man (May 16, 2008)

Great work!

A double motor engine too! It must be a good puller. 
I couldn't find it in any catalogs do you know the mfg date?


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## gunrunnerjohn (Nov 10, 2010)

With magnatraction and 12 driving wheels, I figured it would be a strong engine. Before the conversion, I held it back and cranked up the throttle, it has a nice strong pull. That's when I decided it would be a candidate to spend the money for the conversion. 

It's old enough to have a mechanical E-Unit and new enough to have had the early electronic horn. The instruction sheet is dated 1994, not that that means much. The exploded parts diagram is dated 1986, that's probably closer to the real time period.


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## servoguy (Jul 10, 2010)

I am very interested to find out how well it runs at low speed. How much did the circuit card cost? What I found on the web site was $69. I didn't find the sound card.

BB


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## gunrunnerjohn (Nov 10, 2010)

Yep, it's the $69 one. They have a more expensive one only for DC motors, they offer cruise control.

The low speed performance of this conversion isn't any better than plain transformer control IMO. If the track voltage and/or track condition changes, so does the speed. I tested it and got some variation, so I cleaned all the track and did it again, worked better. This is on a small test loop on my workshop floor, no reason to believe a large layout would be better.

The best low speed performance is with some sort of cruise control. I have another engine with cruise control and DC motors, it creeps along the rails at a snail's pace if you want it to, and will pour all the power it needs to haul a long train and keep that speed. That was a factory installation on a Lionel DASH-8-32 Amtrak engine. I got lucky scoring that one, and it sold me on cruise control.

Bottom line? If low speed performance is important to you, spend the extra money and use a DC motored engine for your conversion.

The sound card is the RailSounds Commander, look for that name.


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## servoguy (Jul 10, 2010)

After I read their description of the board, I came to the conclusion that they knew something that I didn't know, or that they were stretching the truth. Now it appears they were stretching the truth. Problem is this: There is no feedback from the motor to give the controller speed information, and the AC motors have a 2:1 torque ripple. If I were to add a tachogenerator to the motor and close a tight feedback loop around the motor using the tach for feedback, I could get good low speed performance. I haven't found a place to put the tach and couple it to the motor. I have a 2333, 2343, and 2353 which I would like to modify with a tach but that may have to wait for later.

The DC motors work better for 2 reasons: They have 5 poles instead of 3 which reduces the torque ripple significantly, and, because they are DC motor, you can use the back EMF for velocity control. This is probably why the DC motors work well at low speed. 

BTW, a tachogenerator works much better at low speed than an encoder. An encoder has trouble with Nyquist at low speed as there are not enough pulses from the encoder to accurately measure the speed. Also, with a tachogenerator, I can make a totally analog speed control loop which would be superior to a digital loop for this application.

BB


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## gunrunnerjohn (Nov 10, 2010)

Well, they make no claims for A/C motors and cruise control, AAMOF, they specifically told me that they have no A/C motor controllers with cruise control. I'm not sure where they're stretching the truth, can you point that out?

What I can tell you is, the one engine I have with speed control works like a champ, it's capable if literally inching down the rails at a constant speed. Since it's a factory installation, I'm pretty sure they have the axle speed sensor, I'll have to dig it out later and see.


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## servoguy (Jul 10, 2010)

When they speak of 100 speed levels, it implies that they can run slow. They never do say so, though. 

It is likely that the factory installation has the speed sensor on the motor, not the axle. This would work better since the motor turns much faster than the axle.

If I devise a speed control for an AC motor, I will let you know how well it works.

BB


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## servoguy (Jul 10, 2010)

I just took the shell off of a 2353 that I have and there is plenty of space to add electronics and a tachogenerator. They even left a little bit of the motor shaft sticking out of the gear so it should be possible to easily add a gear to the shaft to drive the tach. Now I am getting ideas. I have a 2023 Alco that has a vertical motor with no space at all to add anything. I will have to look at it again. 

Gunrunner, do you know what kind of waveform your new card uses to drive the motor? I am thinking if "pulse power" was used, it might be possible to drive the motor very slowly. Pulse power was invented back in the '50s for HO. If I can find a diode, I might try it tonight.

BB


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## gunrunnerjohn (Nov 10, 2010)

I have no idea what they're using to drive the motor, I just bought the kit and put it in. Since they don't specify in the documentation, it's hard to say. I know that some of the DC kits use 20khz pulse drive.

I put the DASH-8-32 on the tracks, and it's low speed is about 1" a second, and it'll drag a bunch of cars at that speed. The sensor isn't on the wheels, and I don't feel like taking the shell off, it's somewhat of a PITA to stuff all that stuff in again. The speed control is light years ahead of the A/C engines, either my upgrade or the factory Lionel models.


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## servoguy (Jul 10, 2010)

I just ran some tests using half wave AC (pulse powers) with a 2023 and a 2353. They will run slow using half wave AC and don't stall, but the speed is not consistent. I have a small loop of O-27 in my bedroom, and the track is not in very good shape so there is significant voltage variation around the loop but I think that the biggest problem is variation in friction. When the loco goes into a curve, the wheels have to slip, and the loco slows way down. It then speeds up on the next straight. The bearings in the engine and cars (I am using Post War cars) have journal bearings which have a higher friction at low speed than they do when they are running faster. This is typical of a hydrodynamic bearing. Back to the old proverb: Closed loop beats open loop every time." Time to add a tachogenerator and do it closed loop. 

BB


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## tjcruiser (Jan 10, 2010)

John,

I did miss that link earlier ... thanks for the heads-up (again)!

TJ


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## gunrunnerjohn (Nov 10, 2010)

FWIW, I didn't mention that the DASH-8-32 kept that speed around the corners and on the straight, it was rock solid. Clearly, speed control is the way to go for slow speed control.


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## servoguy (Jul 10, 2010)

Gunrunner, you confirm that closed loop is the way to go. 

BB


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## servoguy (Jul 10, 2010)

BTW, using pulse power, the armature in the 2023 will run as slow as 2/3 rev/sec which is 40 rpm without stalling. I think the engine would take an hour to go around the track I have on the floor but I don't have the patience to wait for it. I had to clean the track to get it to keep from stalling. The motor was turning but the train wasn't moving. I got the oil off of the track, and now it keeps moving. The 2023 is a single motor Alco with not so good MagneTraction. The 2353 doesn't stall. Twin motors and good MagneTraction.

BB


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## gunrunnerjohn (Nov 10, 2010)

Yep, I never doubted it. I've never seen any speed control for A/C motors, and I did want to convert that Conrail engine to TMCC, so I went the cheap route. I'll probably pass on the RailSounds and maybe just stick the old horn back in and wire that to the TMCC controller.

I'm going to put the full package into the Williams GG-1 that I got, I only have $70 in it right now, so it can afford to get the deluxe package. It has two really large DC motors, so it should be a puller, the shell must weigh at least 3-4 pounds! In normal mode, it really rockets down the rails, so it has plenty of power.

As usual, the big challenge will be getting the electrocouplers installed. At least the trucks come off cleanly, they're not on the power trucks. Of course, since the couplers I have are Lionel, and the Williams hardware is different, there's going to be a kludge somewhere there.


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## gunrunnerjohn (Nov 10, 2010)

The SD-40 has twin motors and 8 wheels have magnatraction, which was one of the reasons I picked it for the conversion. I want some "pullers" in the stable with TMCC capability.


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## servoguy (Jul 10, 2010)

One of the nice things about the 2023 and 2353 is that they both have coil couplers. No conversion necessary. The 2353 also has 8 wheel MagneTraction. 

Now the next problem is to keep the couplers from uncoupling by themselves. The friction of the PW cars limits a train on O-31 track to less than 20 cars. I don't really want to wire the couplers shut and 20 cars is difficult to handle on the layout I had in my apartment.

The newer cars with the low friction bearings and tapered wheels pull much easier so the train can be longer. 

BB


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## gunrunnerjohn (Nov 10, 2010)

Are these old style coil couplers, like pre-war couplers? The question is, are they the same electrical characteristics as the new ones designed for command control?


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## servoguy (Jul 10, 2010)

Yes, they are similar to the prewar couplers. Lionel used them on most of the O gauge trains after the war. The magnetic couplers were used on O-27 sets until they changed everything to magnetic couplers. I don't have any data on either style of coupler, but the old ones ran off of the track voltage, so they should work. I assume the new ones are driven by a DC signal since that is easier to do than an AC signal. The coils on the 2353 measure 5.5 ohms. I didn't measure the inductance but I can if necessary.

BB


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## gunrunnerjohn (Nov 10, 2010)

Wait, I'll go measure one of the new ones, I still have a pack of them in the box.

I get around 9 ohms. It takes a minimum of 12VDC to trip these, and at that voltage they're drawing a bit more than an amp.


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## gunrunnerjohn (Nov 10, 2010)

I tried an old post-war coil coupler, and at the same 12V it draws over 1.5A, so I'm thinking you may want to buffer those with a relay or Darlington transistor to avoid damaging the TMCC board.


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## servoguy (Jul 10, 2010)

You could put a resistor in series with the coupler and/or ask the manufacturer if the old coupler work with the new electronics. The couplers on the 2353 are mechanically quite different than the ones you installed on your loco. 

BB


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## servoguy (Jul 10, 2010)

At 12 VDC, the old coil coupler will draw a little over 2 amps assuming it is 5.5 ohms. The 9 ohm new coupler will draw 1.33 amps. 

BB


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## gunrunnerjohn (Nov 10, 2010)

Well, actual current measurements were a bit lower than that. Could be connection/lead resistance, I didn't spend too much time on it. I realize what the computations say, I was using empirical measurements.

You're missing the point, I was doing this for you, I have no old style couplers that I have to match.  I'm using the electrocouplers that are designed to interface directly to these TMCC controllers.


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## n1ywb (Feb 4, 2011)

How about using a hall effect sensor on the rotor?


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## gunrunnerjohn (Nov 10, 2010)

n1ywb said:


> How about using a hall effect sensor on the rotor?


Not sure what this is in reference to.


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## servoguy (Jul 10, 2010)

Hall effect sensors can be used to make an incremental encoder to measure the speed of a motor. It is a possibility. There are some other ways to do it, also. 

BB


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## gunrunnerjohn (Nov 10, 2010)

While hall effect sensors will do the job, there's the matter of the actual installation of the sensor and magnet. FWIW, that's the way that many Lionel products do the trick. Of course, some of them like my Phantom locomotive have a microswitch and a cam on the axle, most certainly low-tech!


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