Marx 666 Locomotive Buzzing

The wonderful world of Marx Mike !

Been tinkering with Marx for a couple of years now.

The sound you hear is most likely the E Unit which allows for change of direction.  In Marx it is a 2 position E Unit whereas many Lionel Postwar engines were 3 position E Units although they did produce some 2 position ones.

The buzzing is normal produced by the coil.

The smoke units in the 666 and many others are unique and for a short time produce plenty of smoke until you need a refill after about 6 laps.

Dave

You can take some pink or yellow fiberglass insulation, roll it up in your fingers about the size of a pea, and stuff it down into the stack beside the heating element.

Don't block the smoke stack completely.

Put a few drops of smoke fluid into the ball and it will smoke for much longer that usual.

You have just made a larger reservoir for the smoke fluid.

Soo Line and RoyBoy - thanks for the tips.

The Marx 666 is really a very good locomotive. It is fairly heavy at 2 lbs 3.6 oz, with a diecast shell, so that helps with the traction. It has a good motor, and a compound gear train with a ratio of 8.5 to 1. It runs really well over a wider range of voltages than many other Marx locomotives, and it has good pulling power - even at slower speeds. Here is a short video of my 666 pulling twelve cars without any problems. I just wish it didn't buzz so much.

Nice video, Mike! I have a couple 666s, and to the best of my recollection, neither makes anything like that buzzing sound. Perhaps the E-unit is the culprit, but I defer most of the complicated stuff to Bob Testa, who goes by MarxMotorMan. He's kept my small fleet of vintage Marx engines rolling, and solved some really knotty issues in the process, and his well-deserved charges have IMHO been very reasonable. I think he may be on this forum, but if you're interested I can shoot you his email address. Good luck!

Gotta be the e-unit.  I have several of these and they don't buzz that loudly.

Good video but a little hard to tell about the noise.  Could be the e unit but it also sounds mechanical.

Is the sound just as prevalent on curves as straights?  Are the wheels tight on the axles?  Are the bushings all worn?  Try bench testing.  If you determine it is the e unit,  you can easily by-pass it and have the engine run in forward only if you don't mind giving up reverse.

With Marx, I have found that two of the same engines (666 for example) will exhibit different sounds.  The tolerances were not very exact on Marx and mileage would affect tolerances as well, producing different sounds.  I have seen two 666s, one with a quiet e unit and one more noisy.

The charm of Marx!

Once one acquires the Marx Santa Fe #21....a whole other cat !  Basically a motor in a tin can.  Different noises again.

These 666s are very cheap to acquire and having parts on hand will become essential to keeping a Marx fleet working.

Soo Line

I recently acquired the 666 from an auction on ebay. As soon as I got it, I removed the engine and gave it a thorough cleaning and lubrication. I cleaned the commutator and brushes. I bench tested it, and it was buzzing. I tested it on the tracks without any cars, and it was buzzing. Then, I attached some cars and it was still buzzing. I dont think the noise is mechanical. The only other locomotive I have that buzzes is an old (early 60s vintage) Lionel 246 locomotive with the motor sealed in a plastic housing. This was included with my very first train set when I was a boy. It still runs pretty good, and requires minimal maintenance. My boys used it, and now my grandchildren are using it.

Regarding the Marx 21 diesel Santa Fe, I have found that these have a tendency to derail very easily on curves if they are going too fast. Probably because they have a higher center of gravity than the steam locomotives. The 21, in many ways, is like the 999 in that it can only operate effectively within a very narrow band of voltages, it only has two speeds - fast and stop, and is not a good low-speed puller. But it's still fun.

Yesterday I did some testing and time trails with my Marx 666 locomotive. I produced some interesting results. First let me describe the test rig. I have a loop of 0-31 gauge tubular track, and the total center-rail length is 13.4434'. I have a 275 watt Lionel ZW transformer, and I have power applied in two separate equidistant points along the line. I have a digital multimeter to monitor the track voltage. I used a lock-on to connect the red and black probes. I have an inexpensive clamp-style amp meter to monitor the amperage from the hot wire between the transformer and the track. I also have a 10 turn loop in this hot wire to improve the accuracy of the amp readings. For the time trial, I used the stopwatch feature of my Android phone, and timed the train over 5 laps. I tested just the locomotive at 7 VAC, 8 VAC and 9 VAC. Outside of this narrow band, the locomotive either would not move or would move so fast I was afraid that I'd derail and damage it. I then connected a tender, three freight cars, and a caboose and repeated the time trials at 7, 8, 9, 10 and 11 VAC. This band is wider, and the train would not move at less than 7 VAC, and would run too fast beyond 11 VAC. Below is the velocity calculations and amp draw:

Locomotive only

Locomotive with 5 cars

I also bench tested the locomotive at 7 VAC, the amp draw was 1.76 A, and the power was 12.32 watts. When I ran the locomotive only at 7 VAC, it's velocity was 62.1 mph (scale), amp draw was 1.9A, and power was 13.3 watts. When I attached 5 cars and applied 7 VAC, the train's velocity slowed down to 29.2 mph (scale), the amp draw was 2.1A, and the power was 14.7 watts. So, I produced the pie-chart below, to show how much power was required to overcome the drivetrain resistance and electrical inefficiencies, to move the weight of the locomotive, and to move the cars.

I also made some tachometer readings and did a gear train analysis as shown below.

I should note that the power requirement represented by blue area of the pie chart includes the cumulative friction loss of the drivetrain and the electrical inefficiencies, the power required to illuminate the headlight, and the power required to operate the smoke unit.

That is indeed your e-unit buzzing.Some marx can be louder than others same with some of the Lionel MPC era trains have noticed over the years.

One can have several 999s or 1666s or 666s and may have a loud one .

Have noticed that over many years, have not noticed it for some reason on the 333 Marx steam engines as i have 5 or 6 of them and they all are not loud.

On other hand one of our 1666 marx engines is loud similar to yours in video.

I hooked up a variable-voltage DC power supply to my track, and when I ran the 666 on it, the buzzing went away - completely.

@Mossback Mike posted:

I hooked up a variable-voltage DC power supply to my track, and when I ran the 666 on it, the buzzing went away - completely.

Interesting! First, I was not aware the 666 would run on DC. More to the issue, though, I think your experiment may support the defective E-unit hypothesis.

At heart, the E-unit is just a solenoid with some fancy connections, and when fed AC it tends to buzz a bit (or a lot, in your case?), especially if it does not fully activate. Fed DC, it would activate or not, but would probably not buzz. Have you cleaned and serviced it, and if so, did the buzzing change?

The E-unit is operating very reliably on both AC and DC power - except on AC power it buzzes. The only interesting anomaly is that the 666's headlight isn't working on DC power. Recently, I replaced the incandescent lamp with a BA9S LED 12V bulb. I had a similar problem a few months ago when I was running a 999 on DC - the LED light wouldn't work, and Ben from Benz Trainz recommended that I should swap the polarity of the lock-on wires. That solved the problem then, but doesn't solve the problem now with the 666. I guess I'll have to take a closer look at this.

Running Marx on DC does quiet things down considerably.

However, some e units don't shift well on DC.   Some do and some don't and I have never figured that out.

As well, smoke units may not smoke,  do to the much lower voltage required on DC.

This is the DC power supply I am using. It is a YUNBO Adjustable Voltage Power Supply Adapter AC 100-240V to Variable Voltage DC 3-12V 5A 60W for Dimmable LED Strip Lights.

https://www.amazon.com/YUNBO-A...id_rp_0_1_t&th=1

These work well - but the 5-pin, B5K on-off potentiometer is not very robust, doesn't last long, and is really a PITA to replace. It is cheaper to completely replace the unit when the pot craps out.

Same here Mike.........bought the exact same unit on Amazon and the potentiometer on mine failed also.

Soo Line: I opened up the case (not very easy), and desoldered the pot, which is physically connected to the PCB via the 5 pins. I have ordered some small SPST rocker switches and some 3-pin B5K pots. I plan to remotely mount the new switch and pot, wire them to the terminals on the PCB, and see if I can make it work. Remote mounting the pot will make it easier to replace when it fails.

This is a follow-up to the off-topic discussion of variable-voltage DC power supplies:

https://ogrforum.com/...c/172471169431713108