Perhaps someone has an answer to this problem.
I have a 1995 or so Rivarossi Hudson that makes a clicking noise about once per driver wheel revolution and the locomotive shudders, bobs and weaves as it goes down the track. It is not smooth in operation.
Since I can return this locomotive, but would prefer to keep it, what could be the cause of this?
I am thinking something is binding and then letting go. Bent side rods? Gear problem? Taction tire problem? (Rivs have traction tires.)
I actually had a similar problem on a Bachmann locomotive and it seems to have cleared up by gently pressing in the the side rods at the cylinder area where one side seemed out of whack to the outside of the loco relative to the other side (no traction tires on that one). I don’t see is as noticably here, but there is some difference. See the attached scan.
When I go it, the locomotive barely budged and needd a nudge to go. Cleaning the wheels cured that problem.
Although it may not look like it because the drivers can slide side to side, all drivers and wheels pass an NMRA gauge test.
Any help from wiser heads will be appreciated.
I don’t know about the “wiser” part, [swg] but that type of noise is usually caused by a siderod hitting something, such as another rod, the counterweight on a driver, or one of the screws holding the rods in place. Looking at your second photo, the screw for the drive rod where it attaches to the front driver on the engineer’s side (top of the photo) appears to be partially backed-out of its hole. This may allow the main rod to come in contact with the head every time they pass, causing the “click”. Another possible source of the noise could be the concave curve in the eccentric rod causing the reverse link to come in contact with the main rod. To correct this, or at least eliminate it from the equation, straighten the eccentric rods or even put a very slight convex curve into them. This will move the lower end of the reverse link outwards, away from the main rod. Unless it’s the angle of the picture, though, I think you’ll find that the noise is caused by that screw head hitting the main rod.
Wayne
I hope it’s that simple. The problem could also be a cracked drive gear. I’ve seen it happen. I had a 4-6-2 that did the same thing and none of the drive rods were to blame. When the drive axle was taken out the drive gear had two cracks in it. When I touched it, it broke apart.
If I am right, the bottom image you posted shows the crosshead guide is bent (downward in that image) toward the wheels. In turn, the main rod is brought closer to the driving wheels, and this causes it to impact the screw retaining the siderod on the first driver. There may be more such problems, but this is the first thing I see after a very quick glance at the second image.
Orienting your engine as you did in the image, gently pry the crosshead guide up, away from the closest driver, and you should notice a difference. I’m talking 1-2 mm at most, so don’t reef on it!
I have to agree with selector. I put that picture into a fancy program I have and sure enough, the right side is bent in toward the drivers. He is also right on the distance, 1 to 1 1/2 mm will do it. All this fancy stuff on this computer and I finally found a good use for one of them.
Let us know if that works. I can measure again if it is still doing it.
LoTek
Thanks for your tips. I did adjust the crossheads and one screw was loose, but the clicking persists.
I turned the locomotive upside down in a foam cradle and powered it directly to the real exposed motor terminals, turning slowly.
The middle driver on the fireman’s side raises and lowers unlike the rest. Just the one driver; just the one side. If I hold it down with my finger slightly so that it does not rise and fall, then most, or all, of the clicking goes away.
Bearing or gear problem do you think?
Also, the clicking and rising and falling are much worse going forward than in reverse.
Sounds like a gear problem to me.
That driver may be slightly out of quarter, or there is a burr or something like flashing that is catching at a certain point in its rotation, including the axle, gear (if it is geared), and the crank pin and hole through which the crank pin is inserted on the rod. You may have to take the siderod off and take a look. Maybe there’s just a lump of dirt or hairs/lint. Taking off the bottom frame cover and looking inside to the gears and axles may show something. Magnification and good strong light will help. I actually took the whole drivetrain apart once on my tiny P2K 0-6-0 once, and had a dickens of a time getting it all back together. But I learned that much, and was rewarded with a good look at the works.
I held a steel ruler to the screen and measured the spacing (gauge) betwen the flanges on the two driver sets visible in the image. The lead set is about 1.5-2 mm wider set than the middle pair. I don’t know what that would translate to in reality, but it may be a factor if it is not an artefact of the image. Also, I would have a close look a the axle of that driver set by removing the cover and looking for a foreign or unwanted object or substance. Also, as Jeffrey suggest, the gear or gears may be the problem.
As others have suggested, inspecting the gears for cracks, defects or dirt is a good idea.
One of the assembly steps in building a steam locomotive kit is to manually push the mechanism back and forth on a section of straight track or a piece of plate glass to make sure the mechanism operates smoothly before installing the motor. Perhaps disconnecting the motor from the drive gears so you can push the locomotive by hand will help you find the problem. If you need to, keep disconnecting things until the problem goes away (i.e. remove the main rods and valve gear, then if that does not work remove either the first or third driver set).
Your description of how the middle driver jumps when the locomotive is run upside down makes me suspect one of the drivers is slightly out of quarter. Mis-quartered drivers are uncommon on factory assembled wheelsets, but it does happen.
I have to agree that this is probably the problem - the gear is on the third driver set, and unlikely to cause the “jump” in the second set.
To check for an out-of-quarter driver, pick a side of the loco to start with, and try to align all of the driver counterweights at the bottom (or top) of their rotation. (It’s easiest to do this with the gears disengaged so that you can simply push the loco to align things, but it can be done using the motor, too. An added benefit of disengaging the gears is that, after you re-quarter the driver, you’ll be able to do the “roll on glass” test to check for any other binds.) If you are unable to do so, start with the opposite side. It’s unlikely (although not unheard of) that both sides will have drivers out-of-quarter. Once you have everyting lined-up on one side, carefully, without allowing the wheels to move, visually inspect the other side - the driver with the counterweight out of position with the other two will be the culprit.
If you exercise care to not put the driver on the opposite side out-of-quarter, you may be able to correct the situation without removing the wheelset from the loco. Simply grip the axle with pliers, then, grasping the offending wheel with your fingers, try to turn it in the proper direction. Most locos have fairly loose tolerances for “quarter” alignment, and if you’re able to move the wheel, you should be able to re-quarter it “by eye”. When everthing looks good, carefully apply a drop of ca to both sides of the wheel where it fits on the axle, let it sit for a second or two, then blot up the excess. If the fit on the axle