What Mr DeWitt said..........

Either it's 180 out of phase or a crank has slipped or both or more. The rod that is on with the cranks nowhere near the same position relative to each other needs to be removed, and both cranks set in a similar alignment and then try to fit it on. Check the fit of the boxes in the pedestals. Clean and check the joint between the flycranks and the axles for keys and for stampings to show if they are both in the correct side.

Honestly........ this isn't the space shuttle.

I have worked on several siderod engines, here are my thoughts.

Flipping the axle in this case will do you absolutely no good. You will just make the problem appear on the opposite side.

The rods could be different lengths, for some really strange reason. However even if they are this will not solve your problem. The degree of the two cranks with the rod on are the same, and the other side the cranks are widely off. If they were closer, I would say it was worth investigating.

I would do as several others have suggested, verify no keyways have sheared on the cranks. If you visually can't tell, mark the crank/axle with a line, then use the jack to rotate each crank. It might spin on the axle and give itself away.

One other slim possibility is the axle has broken inside the wheel or bearing. Highly unlikely, but if you work around this stuff enough you see improbable things.

I also think the gearing is a red hearing, I have had several cases apart and the axle is solid with the gear press fit on. I doubt there is an issue in there.

I was going to recommend the same thing. What might look like a key in the keyway could be dried grease and dirt. Those cranks can get pretty dirty if the crank pins are over-greased. That stuff flies everywhere!

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The suspense is killing me. Looking forward to a solution report.

Me too. I will bet money that the front right counterweight turned on the axle. (Or rear left since I don't know if this is the lead or trailing truck)

Bill - I took a look at our two 45 tonners today to get a better understanding of the axle/crank arrangement. (One built in 1941, the other built in 1950.) The one thing I didn't realize is that the keyway does not break through the end of the axle. The keyway begins 1/4" to 3/8" past the face of the axle end.

Here are some photos I took, with recommendations.

Crank before cleaning; note the grease and dirt packed in the keyway of the crank:


Crank after cleaning:


I would recommend digging out any grease or debris with a flat bladed screwdriver. Afterwards, flush with brake parts cleaner to get a better view of the key.

One last photo that shows the depth of the key:



It's hard to tell, but the key is rounded at the end.

The fact that the keyway doesn't break through the end of the axle will make it more difficult to find the sheared key, if it does indeed exist. You might be able to see something after a thorough cleaning, though. I'd also try tapping on the visible portion of the key with a punch to check for movement.

Once again, good luck! Please keep us posted on what you find.

Take the rod off or pull the locomotive with the rod on per Kelly. Move the locomotive so that the crank pin and axle center hole on one axle are vertical. Check plumb with a level. Go to the other side and see if the crank pin and axle center on that side are level (i.e., quartered). Do the same on the second axle. This isn't a precision check but should tell you if there is a gross problem where a key is sheared and a crank has spun on the axle as well as which axle has a problem.

For everything to turn smoothly, the axle spacing has to be the same on both sides, the rod pin spacing has to be equal to the axle spacing, crank pins on the same axle have to be at 90 degrees to each other, and throw of all the crank pins from the axle center must be the same. Don't forget that there needs to be a bit of clearance to prevent binding when one wheel raises and the others don't.

This is where we need a "like" feature. Really interesting post.

You probably don't have an Ashton quartering gauge laying around, but maybe you can make a crude one that will improve the accuracy of the plumb-line test if you don't trust your eye.

The Ashton gauge was a Y-shaped tool, with a symmetrical pair of legs that can be squared on the crankpin, and a center that can be slid up and down the leg of the Y to match the throw length. It contains a weighted needle that always points up and can be compared with a degreed scale to see if the two sides of a crank axle are really 90 degrees apart (or failing that, if all are the same). A search on "Ashton quartering gauge" returned an image of this tool in use.

It might be possible to make a crude one out of a thick sheet of metal. Cut an angle out of one end, symmetrical around a scribed line down the leg of the Y. Put a slot at the base of the Y, and attach a lathe center or knob. An auto shift knob might work, if it will find the axle center. Attach a plumb bob and a protractor. This will work with the axle in any position.

Aarne Frobom
Plumb, Michigan

Superbly stated, a very clear explanation. Note that the crank pins on the inboard axle (the one toward the center of the locomotive) do not appear to be 90 degrees from each other, it looks more like 30-45 degrees.

PC

It doesn't matter how many degrees so long as both wheelsets are the same.

Just keep in mind that to "shear" one of the keys on those cranks would require extreme forces on one side and one crank only. Seems unlikely in normal operation.

Those cranks are probably pressed on with the same forces used for a wheel to axle fit.... Spinning one of those ain't happening short of a major collision.

If an idler axle somehow got "locked to the rail" and the rods pushed hard enough to shear the key I would expect about the same damage on both sides, and the rods would be bent/damaged.

Seems if the cranks are indeed out of proper phase it would be an assembly / repair fault. Perhaps someone did an incompetent job making a replacement axle and cut the key seats wrong, then the rods never fit and they just set them aside. Seems far fetched to me.

Or someone jacked up on one crank pin and put more of the loco's weight between the axle and the pin which might (a real stretch) shear the key, but that seems implausible to me.... It would probably take a hundred tons pressing on the axle with the crank fixed to get them to rotate. And this is a 45 tonner with weight on 7 other wheels...

If properly done those press fits between axles and cranks will not rotate. Press fits have been around along time, when was the last time you heard of one that was properly done failing ???

In the aerospace industry (jet engines) and some car manufacturers they do "cryogenic" press fits. They take properly designed mating parts and "dip" one in liquid nitrogen for a few minutes then place it on/in a mating shaft/bore at room temperature. Once all the parts warm back up to room temp the fit is extremely secure.

The key is mostly for ease of alignment while the parts are press fit together, you have big heavy parts hanging from a crane, the ability to rotate them into axial alignment by hand while a 100 ton press is forcing them together is very limited....

I would bet you could remove the key after the press fit and things would work just fine. But keys are cheap and they just leave them in place.

I also doubt that these keys are intentional "shear keys", there would be no need for those since the wheels would slip on the rails if too much force came from the side rods. Many mechanical transmissions have intentional "shear keys/pins" to protect the more expensive parts (gears, motors, etc) from damage. But in this design the wheels can just slip on the rail head before forces get large enough to damage the transmission.

All good lawn mowers have a aluminum shear key connecting the crankshaft to the flywheel. This is the mechanical equivalent of the electrical fuse. When the mower is running at speed and you hit a big rock with the blade the shear key fails by design which acts to dissipate the rotary momentum of the flywheel and keep the energy in the flywheel from bending the expensive crankshaft. A 50 cent aluminum key "gives it's life" to save a 50 dollar crankshaft.

Freight car axles/wheels have been press fit together forever with out a key and when done properly the wheel simply does not rotate on the axle. Except maybe in a runaway train where the brakes get the wheels red hot, or earlier wheels of cast steel when the wheel fails.

Cheers, Kevin.

So perhaps someone had the cranks off and put the wrong cranks back on the wrong axles.

Just trying to find a logical explination

It's like my Norwegian friend said "if is ain't one thing it's two things".

I have never worked on one of these but I will give my two cents. It seems this is not a side rod or axle problem but a counter weight problem. I would remove the side rod, then I would put a bottle jack under one of counter weights while it rests at the three o clock position and jack it up slowly. I wouldn't put much force on it perhaps 2-4 tons. Have someone watching the other side. If anything is cracked or broken (including a axle) the counter weight will move and everything else will stay put. This would also be effective if you suspect the key is broken or missing.