I normally work as a heavy equipment mechanic and I have seen many sheered key pins even on equipment that is only a few years old. Once you get space between the key on either side, it will pound the key every time it takes a load. It is worse if you are dealing with a wheel that changes directions as it pounds one side then it pounds the other. This constant compression and stretching is murder on steel. This sometimes happens hundreds of times a day just like it could have with this locomotive. When I put new keys in I am not happy unless I have to pound it in with considerable force.

Concerning pressed axles on wheels. If the engineers who designed that pressed wheel thought it would have stayed in place, they wouldn't have designed a slot and key to keep it from moving at some point. It a wheel has a slot and key design and you take the key out of it I can almost guarantee that wheel will start to rotate around the axle at some point no matter how much force was used to press it on.

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I have lost track but has anyone mentioned the possibility that the axel is not shimmed in the frame jaws?

That would require the box being missing which could certainly make the rod not fit but would be so obvious as to be unmissable...... so this thread wouldn't be necessary to start with. It also wouldn't cause the different crank angles.

Bill -

I didn't get involved in this thread from the get-go because I absolutely would have been unable to offer any help. Now however, I have read through all the comments and ideas to solve the problem. One thing I did notice is that no one seemed to ask the question, would the unit be operable WITHOUT the side rods attached? The second axle on each truck then would be an idler. Just wondered.

Les

So far there is no evidence of a sheared key. I said unlikely, but waiting for evidence.

Improperly assembled press fits will indeed allow one wheel to "Stall" a 600 ton press while the other wheel falls off, operator error.

Yes you can rotate a part while it is being pressed into a bore, one reason for the key to maintain the alignment designed into the system.

Broken axle inside the wheel is a possibility, possibly caused by an impact (but there are no other signs of impact, one would expect the crank pin or rod end to have a scrape mark or two).

I'm betting someone tried to make a new axle, fudged it up and ran out of someone else's money to fix it correctly.

Look at the evidence, a normally working loco stored without any obvious signs of a collision or impact with an undamaged crank pin and the undamaged side rods stored on the deck..... If the key sheared or the axle broke the rods/journals/pins would at least have some evidence of distress ? Some kinking, scraped paint, gouge marks where the cranks hit a wayside obstruction....

Heavy construction equipment is a whole different ballgame, those operators try to bust stuff for the fun of it (at least some of them seem to enjoy "testing" the strength of the machine)...... And there is no steel wheel on steel rail interface to act as force limiter....

I'm betting a fudged repair job to "win", parts that won't fit back on the loco stashed "out of sight out of mind" and everybody walked away without mentioning it again.... It was stored out of service, just maybe because they didn't know how to fix it properly so they got an "early quit".....

And I'm betting a sheared key to "place" and a twisted axle to "show"....

But this is a fun parlor game;

"Guess who broke the loco";

Was it Bob in the cab closing the throttle too fast, or Jill who left a big chunk of battleship alongside the tracks for Bob to hit, or Stan who made the axle wrong and then retired without telling the boss "Big Bill" ???? Tune in next week to see the next installment.....

Seriously, good luck to the folks putting this back together, at least you have all of the parts.

Don't underestimate the lack of quality control in the "good old days", I restored a 1920's Plymouth Locomotive and there were the remains of a broken tap in one blind cross hole in a critical shaft of the transmission. They just left it there and put a shorter bolt in that hole to cover it up. Nobody knew anything about it for 80 years until I did a complete tear down and took everything (except for the press fits) apart for refurbishment. And by then it was "out of warranty".....

Cheers, Kevin

Oh, for those that don't know the term "early quit", it's a old railroad term (may now be considered obsolete).

On the railroad the "yard" jobs had a scheduled "duty time", you started at noon and worked to midnight and got 12 hours pay (old days, pre 1970's). You had a list of switching to do, and you waited for arriving trains to be switched while you were on duty.

If you finished all your assigned tasks in say 7 hours and no trains were arriving in the next 5 hours (past your 12 hour day) you got an "Early Quit", you could go home and still get paid for 12 hours of yard duty.

When business was good "early quits" were rare, as things slowed down you got lucky more often. But then management started reducing the number of crews in the yards so "early quits" became rare again.

Cheers, Kevin.

He didn't say that it was a normally working locomotive. He did say that they recently got it and the rods were already off of it.

Scraped paint? Well what are those fresh marks on the top of the counterweight on the right wheelset of the second photo on page 1? If this loco was rolling along and that counterweight came down directly on some sort of object laying next to the track, that force I would think would be enough to either shear the key or twist the axle.

I see lots of evidence pointing to either a sheared key or twisted axle on that right side wheelset in the second photo.

Tom F wrote;

"I normally work as a heavy equipment mechanic and I have seen many sheered key pins even on equipment that is only a few years old. Once you get space between the key on either side, it will pound the key every time it takes a load. It is worse if you are dealing with a wheel that changes directions as it pounds one side then it pounds the other. This constant compression and stretching is murder on steel. This sometimes happens hundreds of times a day just like it could have with this locomotive. When I put new keys in I am not happy unless I have to pound it in with considerable force."

With respect, what you describe is not a true "press" (or interference) fit. It is a "friction fit", similar but different. If you can take it apart in the field without a large (100 ton plus) press it is a friction fit and not a press fit.

A large press fit cannot (normally) be disassembled with a "gear puller".

A friction fit is usually tightened up with some kind of tapered "collet" with multiple setscrews. It usually has a key to help transfer the torque between the shaft and wheel. A friction fit does not significantly change the stress levels present at the metal to metal interfaces.

A true press/interference fit significantly increases the stress applied to the metal at the interfaces. The bore presses significantly against the shaft which presses back. When properly designed and assembled a true interference fit approaches the strength of the metals involved.

Cheers, Kevin.

Rick wrote;

"If this loco was rolling along and that counterweight came down directly on some sort of object laying next to the track, that force I would think would be enough to either shear the key or twist the axle."

Ok, that's plausible, but consider;

1) There are one or three other axles (depending on direction of travel) with the same cranks that went by the exact same trackside object and missed it with no damage ? This is somewhat possible since the cranks will "bottom out" with a periodic distance between the "troughs". Axle #1 could have missed the obstruction since it was "up" while axle #2 hit it because it was "down". But what about the other axles and the end plates (usually about 1" thick steel), no other damage anywhere else on the loco to indicate a collision ?

2) Even if one crank (out of 8 total) hit an obstruction that raised only that crank it could apply at most about 6 tons of extra load to that crank (44 tons / 8 axles = 5.5 tons). How could 5.5 tons of upward force against a crank pin shear the key between the axle and crank but not damage the crank pin or rods ??

3) The loco has an equalized suspension system, if you "push up" ~7 tons on one axle the other 7 axles "push down" by the equivalent 1 ton each. If you hit an obstruction with one axle crank the whole locomotive raises up and the load gets distributed to all the wheels.

4) The axle center to crank pin distance is about a foot (give or take) so we get about 14000 ft pounds of torque between the crank and the axle, the only thing resisting this is the other crank/rod (or a traction motor). 14000 ft lbs of torque is not very much for a locomotive transmission system. If that design can't tolerate that kind of "torque disruption" then I think 44 ton GE's would have a terrible history of failures.....

I'm still betting on a botched repair job, not enough evidence that a collision with enough force to shear a crank to axle press fit key while not doing much other damage happened. That is one "magic sheared key"....

Cheers, Kevin.

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Thanks Kelly, I really respect the quality of the work you all have produced and shared with us all.

Cheers, Kevin.

You can certainly use it without the side rods, but the problem is that if you use it WITH the opposite engine/truck, and assuming both engine/gen/motor combos are responding similarly, the end without side rods will be slipping it's drive axle badly when the 'good' end is still well within it's limits of adhesion. Could be damaging or dangerous if not watched closely.

Talk to the mechanics at the outfit you got the loco from.

Actually as far as running her without the rod, If you are only moving her alone or with a light load, run only one engine. We do that constantly with our 44 tonner, on the centercab GE locomotives the gen-set at each end only powers the truck under it. This was part of the selling point advantages of the design, fuel economy, same as the modern co-gens, only burn as much diesel as you need to move the load, one engine not enough, start the second and continue... So until the crank pin timing is fixed, operate her with the engine above the good axles and only run the diesel above the problem truck every so often to keep it in good condition (diesels don't like to sit for long periods). While you run her on the good end start looking for a spare idler axle from another 45 tonner.

One thing I am surprised no one has mentioned as a theoretical cause for the timing issue (if it is a sheared key and not a manufacturing error) is that she ran in an industry. A lot of industries don't have the best track, if one axle jumped rail and the counter weight hit the rail, that might be enough to shear the key, especially if it was over a pit and she was moving with a bit of speed.

Not sure which I would put money on, sheared key or bad machinist. The only way to find out for sure, will be to pull the counterweights.

Rich C.