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HELP! N Scale Loco Wheels Won't Move

13K views 21 replies 12 participants last post by  jshack 
#1 ·
Hello All,

I am vary new to model railroading. I purchased an older train set from a train museum gift shop and cannot get the locomotive running. When it is on the track the light turns on and I can hear an electric humming sound. The wheels will not move on or off of the track. I removed the case and pulled the engine and the wheels are able to move and roll. I now have lubricated all of the gears and the wheels roll smoothly until the motor is back in, then they stop. Please help! I am at a loss of what to do next. I love this old train and would love to get it working. Take a look at the pictures (including one of the grease I used).
 

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#2 ·
You've done the right thing by cleaning and
replacing the lube in the gearing with LaBelle's.

The reason the wheels won't turn with motor
installed is that is uses a 'worm' gear.

However, the motor should turn the wheels.

You can test the motor outside of the frame
with the motor shaft and the 'worm' gear free
of the other gearing. Set your power pack
to about 1/3 'on'. Use wires from the 'track'
terminals and touch them to the actual tabs
on the motor. If it doesn't run try turning the
'worm' gear by hand and see if it breaks loose.
(The bearings may have 'frozen'). If it runs,
apply a drop of Labelle's on the bearings.
Exercise it forward and backward before
reinstalling.

Note: If the 'worm' fits too tightly in the
gearing that could 'stall' the motor.

If the motor doesn't run in the test you may
have to replace it.

Don
 
#4 ·
See if you can connect the motor leads to the track by splicing in 2 wires near the motor, just twisted on, not soldered or anything. If there's power in the track and the motor doesn't spin then the fault is with the motor, or its leads to the wipers on the back of the wheels/some kind of open circuit, or polarity problem..
You could just cease hassling with this loco and buy another. Since it appears to be that you're not in DCC but in analog DC there are some very very inexpensive ones on ebay...
 
#5 ·
In the third photo down, it looks like the tie rods on the left (top, in the picture) are misaligned. If they are bupinding, that would keep your loco from moving.
 
#6 ·
I probably don't know what I'm talking about, but in the 5th picture the linkage connecting points look misaligned too. Looks like it'd lock the wheels. Someone tell me if I'm wrong.
 
#9 ·
Motor brushes OK?

Hello All,

I am very new to model railroading. I purchased an older train set from a train museum gift shop and cannot get the locomotive running. When it is on the track the light turns on and I can hear an electric humming sound. The wheels will not move on or off of the track. I removed the case and pulled the motor out and the wheels are able to move and roll. I now have lubricated all of the gears and the wheels roll smoothly until the motor is back in, then they stop. Please help! I am at a loss of what to do next. I love this old train and would love to get it working. Take a look at the pictures (including one of the grease I used).
TrainNoob;

You say the motor hummed when it was mounted in the locomotive. Have you tried running the motor outside of the loco with the power pack, as DonR recommended, yet? If it doesn't run the problem may be the motor brushes, or at least one of them. In your photo of the motor, I see one of the brushes sticking out quite far. This is at least partly because that brush assembly is used as a mechanical and electrical link to the tender car that rolls directly behind the locomotive. The brush assembly is the little round silver colored tube sticking out of the bottom side of the motor back near the end furthest away from the worm gear. The actual brush is a round bit of carbon that is inside the tube along with a tiny spring. The brush assemblies were held in the motor only by friction. You could try pushing the brush assembly further into the motor. It's quite possible that the actual carbon brushes have worn out, and if the assembly is too far out, a worn brush can come out of the tube and get caught in the commutator of the motor, which is a very bad thing.
That motor is an old Rivarossi three-pole motor. It goes back to the early 1970s when N-scale was new in the US.
The three-pole motor (modern, better, motors have five poles) and the way-too-fast gearing in these old model locomotives, mean that the locomotive won't run reliably at slow speed. This makes coupling, and uncoupling, cars for switching very difficult.
In short a current-production locomotive will work a lot better than this antique, and I agree that the side rods are messed up. That's another difficult repair in itself. I think you should replace this locomotive with a new one, unless you are able to repair the one you have now. I think that's doubtful. Even if you succeeded, you would still have a very old locomotive that won't run very well.

good luck;

Traction Fan :smilie_daumenpos:
 
#10 ·
Still Trouble

I have connected the wires directly to the locomotive. The light came on, but the motor did not. I also didn't hear the humming that I heard on the track. Does the coal car need to be connected as well?

What are the tie rods? I apologize for my inaccurate description, but I am very new to the hobby. Are they the metal beams attached to the wheels? I disconnected those from the front wheels when I was attempting to access the gears. The wheels move freely without the motor installed (after lubrication).

Traction Fan: I tried pushing the brush assembly further in, but it wouldn't budge. If I were to try to fix this locomotive (I don't have a lot of extra money for a new one). Is there anything else I can try? Would I 5 pole locomotive work on my current track?

Thanks everyone for your help!
 

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#11 ·
the pins in the wheels should line up, very much like the image on the cover of the box do ..the 'drive bar' or linkage should be flat across the wheels, again the same as the image on the cover ...
the other side should be a 'quarter' turn out, either 90 degrees ahead, or behind the first side ..
in the pictures you have the linkage is NOT flat ...
 
#12 ·
You may need the tender attached, yes. On many locos, the tender is part of the circuit.

Just test the bare motor by applying power directly to the tabs and see if it runs. You can remotor the loco, and you'll need to repair the connecting rods if you want it to run. This is a fairly complex, although fairly inexpensive, repair. Probably not something I would recommend for a beginner, unless you already have some electrical skill and a lot of patience.
 
#13 ·
Motor Test

By putting power to the tabs are you referring to the bottom rod and the flat tab on the top of the motor? When I tried last evening I attached the power to the wheel and that bottom rod to have the light turn on with no motor movement. I will give that a try this evening.

If I need the tender attached, do you have any advice on how to test it that way?

Finally, I'm not sure if the tie rods on the wheels are bent, but just disconnected. In my attempt at getting the wheels to spin in the first place I took the entire lower portion of the locomotive apart and disconnected them from the front wheels. I think I may just need to re-align them properly. Any advice? After reading the comments, I have been attempting to do so to no avail.
 

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#16 ·
Rod "quartering"

By putting power to the tabs are you referring to the bottom rod and the flat tab on the top of the motor? When I tried last evening I attached the power to the wheel and that bottom rod to have the light turn on with no motor movement. I will give that a try this evening.

If I need the tender attached, do you have any advice on how to test it that way?

Finally, I'm not sure if the tie rods on the wheels are bent, but just disconnected. In my attempt at getting the wheels to spin in the first place I took the entire lower portion of the locomotive apart and disconnected them from the front wheels. I think I may just need to re-align them properly. Any advice? After reading the comments, I have been attempting to do so to no avail.
TrainNoob;

DC Electric motors, like those used in model trains, have two contacts, often in the form of tabs, that accept the wires that feed electricity to the motor. In the case of your locomotive, one of these contacts/tabs is attached to the "rod" sticking out of the bottom of the motor, and the bottom of the locomotive too. That bottom rod is designed to fit into a hole in the "drawbar" that sticks out of the front of the tender. Under the drawbar, you may find a small spring wire. When the rod is inserted in the drawbar, that wire should rub against the "rod" (I prefer to call it a "post" to avoid confusion with the "side rods" or "drive rods" that are attached to the drive wheels.) They will come up in later discussion. You called them "tie rods" which isn't the right technical term, but that doesn't really matter. I'm just trying to get us all using the same names, for the same parts, to avoid any confusion. I knew what you meant without any special technical terminology. Please don't sweat this sort of thing. I don't. and the other forum members don't either.

So, to test with the tender, You would put that bottom post from the motor into the hole in the tender's drawbar. Then check the wheels on the tender. Some of them will be all metal, others will have some form of plastic insulators, usually in the center part of the wheels. The metal wheels have to all be on the same side. The idea is to get power from one of the rails through the metal tender wheels, then into that little spring on the drawbar, and then into the post on the bottom of the motor.
Power from the other rail goes through the locomotive's wheels on one side, and then through some wiper contacts that rub against those loco wheels. The wiper contacts feed power up into the motor.
Since you have verified that the motor will run when connected directly to the wires from your power pack, we know the motor is not burned out, or broken.

That leaves two possibilities.

First, The power is getting to the headlight, but not to the motor. There may be a loose wire, or bad connection somewhere inside the locomotive. I recommend testing this possibility first, because it's the simplest, and the one less likely to cause you additional trouble. Look carefully to see if you can find any loose wire, bent contact, or anything else that looks odd. If you don't see any problem, you will need a multimeter to test further. If you don't have a multimeter, you can buy one for only $5 from Harbor Freight tools. www.harborfreight.com This meter is shown in the photo below. It comes with directions, and even has the battery already in it.
With the meter set for 20 volts DC you can test the power pack wires to the track, then to the tender and locomotive wheels, wiper contacts and up to the headlight and motor. If you can set the locomotive and tender on the track, turn up the power pack, and read voltage at those two motor contacts (the bottom post, and the other tab on the motor) then electrically everything is OK and you have a mechanical bind. :smilie_daumenneg:

Second, some sort of mechanical bind in the gears, or the side rods. You could test for this by removing the side rods, but there are potential problems. The rods are held onto the wheels by very small screws with hexagonal heads. A tiny nut driver would be the right tool to remove these screws. Also the screws need to be carefully stored, they are very easy to lose. If you decide to remove the rods, I suggest working on a table covered by a white terry cloth towel. The rough texture of the towel will help keep screws from rolling onto the floor, and the white color makes them easier to see. work under a strong light too.
Another thing before you try to take the rods off. Take several clear photos of both sides of the locomotive. Look very carefully at all the rods, and make sure you know what goes where before removing them. If you have the rods off, you will be able to try running the locomotive without them. If it runs well this way, then the rods were what was binding things up. If the loco still won't run, even with the rods off, there is probably a bind in the gearing. I don't think this is likely. It seems like you got the gears cleaned out well, and put new grease on them. It's possible the motor is sitting a little crooked. It needs to be aligned straight down the center of the locomotive. It's also possible that the motor is drawn down too tightly against the spur gear that meshes with the worm gear on the motor.

That's about all I can think of. If you still can't fix the problem, you might see if there is a hobby shop near you that repairs trains. I think you may need someone knowledgeable helping you in person instead of online at that point. If all else fails, replace the locomotive.

good luck;

Traction Fan :smilie_daumenpos:

Wire Technology Electronic device Electronics Measuring instrument
 
#15 ·
The scientific method rules in troubleshooting. In other words, systematically work through the problem, a step at a time, eliminating possible problems as you go by testing or experimentation.

At this point, you need to check the drive train, one piece at a time until you find the part that is bound up. Do you have an exploded parts diagram for the loco? Because you're probably going to need it to get the tie rods back together properly. Anyway, with the motor out of the loco, do the wheels turn? Check the worm gears for cracks / splits. Check for congealed lubricants on the gears.
 
#17 ·
Here's the skinny on that engine of yours.

It is a Rivarossi 0-8-0, made starting about 1969.
Since the motor runs when you have it out of the frame, you have a really good shot at resurrecting the engine.
Those motors are notorious for overheating and melting, but if they are cared for and not over-oiled, they can hold up.
The first thing you have to do is fix up the driving wheels and get the rods on in correct alignment. This is called "quartering", and sometimes can be a very difficult task. Lucky for you, quarting on a Rivarossi steam loco is about the easiest there is, because of how it is designed.

1. Using a jewelers screwdriver, tweezers, and/or a very tiny pair of needlenose pliers, unscrew the the main crank screw on the 3rd driving wheel (driver) from the front. It is the only one with a screw. TAKE CLOSE-UP PHOTO before you remove the screw and be extremely careful not to lose the screw or any spacer washers under it. You need to put them all back in the same order.

2. Once you get that screw out, the rods will all come off. Notice at this point that the siderod (the one that goes flat alongside all 4 drivers) attaches to only the FRONT driver by slipping its fork-shaped end under a pin that is pressed into the driver. Just make a note of this in your head for later.

3. Flip engine on its back. It really helps if you have a block of foam with a groove cut out to hold the engine up (an engine "cradle" which you can buy from model railroad supply stores). If you don't have such a thing, you'll have to improvise. Try rolling up a couple of handkerchiefs or washcloths so you can place the two cloth rolls down with the engine lying between them.

4. There are two screws that hold a cover plate in place on the bottom of the engine. Remove the screws and plate. Be CAREFUL - there are 3 plastic U-shaped piece that slip into slots in the frame between each pair of driving wheels. If they partially lift out, put them back in.

5. Now, carefully lift/rotate, and then drop back in each driving axle until you get all 4 of them in so that
the holes in the outside wheel faces (the "crankpin holes") all line up at the bottom. They can line up anywhere you like as long as they are all in the same exact relative position of rotation, but it is easiest to see that they are lined up by getting them at the bottom. It can be a little tricky, because as you try to drop one back in, it will try to rotate the gear that it mates with and that can rotate the OTHER drivers, making them go out of line again. So when you drop one in, try to hold the other three still with a finger so they cannot turn.

5b. VERY IMPORTANT - Check that the 4 drivers are all placed in the frame with the "hot" driver on the correct
side. As you look at the wheels from the bottom, you will notice that for the two wheels on any axle, ONE wheel has a metal plate slid up against the back of it, but on the other side, you will just see the plastic spoked wheel center with not metal plate. With the engin on its back, and the rear of the engine to your LEFT, the 4 wheels with the metal plates up against their backs should all be NEAREST to you.
If they are not... pull the offending ones out, flip them around and put them back in.
You MUST get them all correct or they create a short circuit and the engine will not run. It is common
for "tinkerers" to mess around withthese, get one flipped around, and then never get it to run again and give up.

6. Once you get all 4 so that their crank holes line up, put the cover plate back on and put the 2 screws back in.

7. At this point, with no motor and no rods, you should be able to smoothly rotate all 4 wheels and they should turn in unison.

8. LAY THE ENGINE ON ITS SIDE.

Put the siderod back on, on one side. Remember that photo you took when you took out that screw? That's going to be important now. You need to put the siderod back on, with spacers, and the other rods that all connect over that one screw on the 3rd driver, just as they were originally. On that engine, I believe it goes:
  • put spacer washer over the threaded tube that is inserted in the hole in the 3rd driver
  • place siderod front fork under the pin on front driver
  • drop the siderod hole over the threaded tube in the 3rd driver (right over the washer you already put there)
  • drop the "main rod" (the one with a larger end on it with a hole in it) over the threaded tube
  • now the tricky part, place the eccentric crank (this is the only remaining piece you haven't connected - it
is a thin, light rod with several joints in it, and the end has a small jointed piece that can rotate.) That last little
piece with the hole sits on TOP of the threaded tube, it doesn't go over it. You have to hold it there while you put the screw through it into the threaded tube, and then turn the screw in with a jewelers screwdriver.
And you have to do all this without losing the screw, or getting frustrated an uttering bad words.

9. When you get the screw most of the way in.... VERY IMPORTANT NOW.
rotate the wheels so that the crankhole (where the screw is) is at the BOTTOM of rotation.
Rotate that eccentric rod (the thing one, sitting on top of your stack of rods on the third driver)
so that the 3 pieces of the rod go straight up - straight over - straight up.
You need to hold it in that orientation while you tighten the screw.

Once the screw is tight, that eccentric rod will be held in that orientation and you should be able to rotate
the 4 wheels and watch that the rods work smoothly.

10. Now do the rods on the OTHER side. And then make sure all 4 wheels rotate and all the rods work.

11. The motor....
Ease the motor in from the back. As the worm gear engages the idler gear inside the frame,
you can just wiggle the driving wheels back and forth a little to engage the teeth and let the motor push all the way in.

12. Put the two screws into the back of the motor to hold it in place.

13. You should be able to wiggle the drivers now. Not turn them, but there should be some play in them.
If there isn't, you don't have the worm gear engaged properly so loosen the motor screws and try again.

14. Apply power to the motor using clip leads from a power pack on half speed (not 1/4 or 1/3 .. some of these old Rivarossi motors won't start turning until you get the power pack up about half way, especially if this thing
has been sitting around for years. Just connect the + and - leads to the silver contacts on the top and bottom of the motor. On the bottom, be sure to only touch the pin that protrudes all the way down . Do not let that lead touch the frame or other parts of the motor, which will create a short circuit.

15. Assuming that works... Look under the tender (the "coal car"). You will notice that for each axle, one wheel has a metal center (the "hot" wheel) and the other side is a plastic center. All 4 metal centers must be on the OPPOSITE side from where the metal plate "hot" wheels are on the engine. If any aren't, you need to carefully use a jewelers screwdriver to pry out the wheel axle, flip it around, and reinsert it. And note the metal wiper strip that goes over the screw in the center of the truck (there are two "trucks" with two axles in each one). Pay attention that that wiper and make sure the wheels and wiper go back in correctly.

16 Connect the engine to the tender by first looking at the flat metal strip that connects the two (the drawbar).
THere is a fine spring steel wire that should be positioned, and slightly bent, so that the end of it lies just to one side of the hole at the end of the drawbar. If it isn't, bend it over so it is. Now, insert the pin under the back of the engine (coming out of the bottom of the motor), into the hole in the end of the drawbar... MAKING SURE to bend the wire over... ACROSS The hole, and then insering the pin , so that the wire is sprung against the pin when it is inserted.

Holding this together, get it all on the track without letting the pin pull out.

This was a very very long dump... but good luck. I hope you can get it to run.
560810
 
#22 ·
Here's the skinny on that engine of yours.

It is a Rivarossi 0-8-0, made starting about 1969.
Since the motor runs when you have it out of the frame, you have a really good shot at resurrecting the engine.
Those motors are notorious for overheating and melting, but if they are cared for and not over-oiled, they can hold up.
The first thing you have to do is fix up the driving wheels and get the rods on in correct alignment. This is called "quartering", and sometimes can be a very difficult task. Lucky for you, quarting on a Rivarossi steam loco is about the easiest there is, because of how it is designed.

1. Using a jewelers screwdriver, tweezers, and/or a very tiny pair of needlenose pliers, unscrew the the main crank screw on the 3rd driving wheel (driver) from the front. It is the only one with a screw. TAKE CLOSE-UP PHOTO before you remove the screw and be extremely careful not to lose the screw or any spacer washers under it. You need to put them all back in the same order.

2. Once you get that screw out, the rods will all come off. Notice at this point that the siderod (the one that goes flat alongside all 4 drivers) attaches to only the FRONT driver by slipping its fork-shaped end under a pin that is pressed into the driver. Just make a note of this in your head for later.

3. Flip engine on its back. It really helps if you have a block of foam with a groove cut out to hold the engine up (an engine "cradle" which you can buy from model railroad supply stores). If you don't have such a thing, you'll have to improvise. Try rolling up a couple of handkerchiefs or washcloths so you can place the two cloth rolls down with the engine lying between them.

4. There are two screws that hold a cover plate in place on the bottom of the engine. Remove the screws and plate. Be CAREFUL - there are 3 plastic U-shaped piece that slip into slots in the frame between each pair of driving wheels. If they partially lift out, put them back in.

5. Now, carefully lift/rotate, and then drop back in each driving axle until you get all 4 of them in so that
the holes in the outside wheel faces (the "crankpin holes") all line up at the bottom. They can line up anywhere you like as long as they are all in the same exact relative position of rotation, but it is easiest to see that they are lined up by getting them at the bottom. It can be a little tricky, because as you try to drop one back in, it will try to rotate the gear that it mates with and that can rotate the OTHER drivers, making them go out of line again. So when you drop one in, try to hold the other three still with a finger so they cannot turn.

5b. VERY IMPORTANT - Check that the 4 drivers are all placed in the frame with the "hot" driver on the correct
side. As you look at the wheels from the bottom, you will notice that for the two wheels on any axle, ONE wheel has a metal plate slid up against the back of it, but on the other side, you will just see the plastic spoked wheel center with not metal plate. With the engin on its back, and the rear of the engine to your LEFT, the 4 wheels with the metal plates up against their backs should all be NEAREST to you.
If they are not... pull the offending ones out, flip them around and put them back in.
You MUST get them all correct or they create a short circuit and the engine will not run. It is common
for "tinkerers" to mess around withthese, get one flipped around, and then never get it to run again and give up.

6. Once you get all 4 so that their crank holes line up, put the cover plate back on and put the 2 screws back in.

7. At this point, with no motor and no rods, you should be able to smoothly rotate all 4 wheels and they should turn in unison.

8. LAY THE ENGINE ON ITS SIDE.

Put the siderod back on, on one side. Remember that photo you took when you took out that screw? That's going to be important now. You need to put the siderod back on, with spacers, and the other rods that all connect over that one screw on the 3rd driver, just as they were originally. On that engine, I believe it goes:
  • put spacer washer over the threaded tube that is inserted in the hole in the 3rd driver
  • place siderod front fork under the pin on front driver
  • drop the siderod hole over the threaded tube in the 3rd driver (right over the washer you already put there)
  • drop the "main rod" (the one with a larger end on it with a hole in it) over the threaded tube
  • now the tricky part, place the eccentric crank (this is the only remaining piece you haven't connected - it
is a thin, light rod with several joints in it, and the end has a small jointed piece that can rotate.) That last little
piece with the hole sits on TOP of the threaded tube, it doesn't go over it. You have to hold it there while you put the screw through it into the threaded tube, and then turn the screw in with a jewelers screwdriver.
And you have to do all this without losing the screw, or getting frustrated an uttering bad words.

9. When you get the screw most of the way in.... VERY IMPORTANT NOW.
rotate the wheels so that the crankhole (where the screw is) is at the BOTTOM of rotation.
Rotate that eccentric rod (the thing one, sitting on top of your stack of rods on the third driver)
so that the 3 pieces of the rod go straight up - straight over - straight up.
You need to hold it in that orientation while you tighten the screw.

Once the screw is tight, that eccentric rod will be held in that orientation and you should be able to rotate
the 4 wheels and watch that the rods work smoothly.

10. Now do the rods on the OTHER side. And then make sure all 4 wheels rotate and all the rods work.

11. The motor....
Ease the motor in from the back. As the worm gear engages the idler gear inside the frame,
you can just wiggle the driving wheels back and forth a little to engage the teeth and let the motor push all the way in.

12. Put the two screws into the back of the motor to hold it in place.

13. You should be able to wiggle the drivers now. Not turn them, but there should be some play in them.
If there isn't, you don't have the worm gear engaged properly so loosen the motor screws and try again.

14. Apply power to the motor using clip leads from a power pack on half speed (not 1/4 or 1/3 .. some of these old Rivarossi motors won't start turning until you get the power pack up about half way, especially if this thing
has been sitting around for years. Just connect the + and - leads to the silver contacts on the top and bottom of the motor. On the bottom, be sure to only touch the pin that protrudes all the way down . Do not let that lead touch the frame or other parts of the motor, which will create a short circuit.

15. Assuming that works... Look under the tender (the "coal car"). You will notice that for each axle, one wheel has a metal center (the "hot" wheel) and the other side is a plastic center. All 4 metal centers must be on the OPPOSITE side from where the metal plate "hot" wheels are on the engine. If any aren't, you need to carefully use a jewelers screwdriver to pry out the wheel axle, flip it around, and reinsert it. And note the metal wiper strip that goes over the screw in the center of the truck (there are two "trucks" with two axles in each one). Pay attention that that wiper and make sure the wheels and wiper go back in correctly.

16 Connect the engine to the tender by first looking at the flat metal strip that connects the two (the drawbar).
THere is a fine spring steel wire that should be positioned, and slightly bent, so that the end of it lies just to one side of the hole at the end of the drawbar. If it isn't, bend it over so it is. Now, insert the pin under the back of the engine (coming out of the bottom of the motor), into the hole in the end of the drawbar... MAKING SURE to bend the wire over... ACROSS The hole, and then insering the pin , so that the wire is sprung against the pin when it is inserted.

Holding this together, get it all on the track without letting the pin pull out.

This was a very very long dump... but good luck. I hope you can get it to run.
View attachment 560810
Glad I found your post. Helped me get the wheels in the proper position. I bought this used for $10.00, this is why it wouldn't run. I also found one of the pins that holds the tie rod and other linkage damaged( I was able to tune the other side) Any idea where I could find this pin, or adapt something in it's place? Does not have to prototypical, just run for my Grandson.
Thanks
Jay
 
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