side rods... reaching their limit

All kinds of stuff can happen:

 

http://www.heavyequipmentforum...er-through-the-roof!

 

 

I like those video's that Rick O posted, steam doing what it was built to do. The video's on the NYC have even faster steam. Reflections of the NYC and Niagara"s last stand excellent high speed action.

As Southwest Hiawatha and Rusty Traque mentioned, Classic Trains had an article years ago titled: The Victimized Hudson - Why did the running gear of Milwaukee Road 102 fly apart at 90 mph plus ?

 

This photo appeared in the article:

 

Lubrication failure, resulting in something broke.

I'm not a mechanical engineer but I have asked this question before so I did some reading on the subject.

 

From what I took from those pages was that the trick is balance. If an engine is well built, like the NW J and the bearings and connections are in good condition there really is not that much stress on the side rods, other then the draft lode and that is the same at speed or 1 phr.

Remember they are not changing direction at speed, they are always in a smooth circular motion.

But, and this is a big but if the roller bearings over heat everything can go out of balance. Even a very small imbalance can cause amplified vibrations and as stated above good-by side rod.

 

I had an old Ford that was thumping when ever I moved the car. I could feel it in the steering wheel it was so pronounced. I thought it was in the motor, or drive train. A friend told me to check my front left wheel bearing, so I did. I could hardly feel any problem with that bearing when I spun it in my hand, but the problem was gone after  I put the new bearing in.

 

My point being that as long as my old Ford was balanced it ran as quite as can be and at far greater RPM's then a steam engine. But, even a small perturbation in the mechanical balance casued  that car to feel like it was coming apart.

 

So to all our engineers I say thank you for staying in school guys, It's your calculations that make all our cool toys possible.

 

I'll tip my hats(I've got more than one) to the explorers, inventors and the seekers of knowledge...

 

Thanks guys for climbing aboard.

 

Cheers,

 

 

Rick

It is not possible to balance steam locomotive drivers. The wheels are going around, the piston back and forth and the rod between them is doing some of each. Locomotive wheels were balanced to take out the tendency to move back and forth in the yaw direction. In the vertical direction the imbalance limited the speed.  The imbalance could cause the driver to go to no force on the rail, but too fast was when the driver lifted. At 180 degrees the driver came down hard on the rail with a force exceeding the weight of the locomotive. This is called dynamic augment.  The track and bridges were designed for dynamic augment.  That extra built in capacity has allowed the railroads today to handle the heavy loads they do.

The slip speeds with a NYC Super Hudson were conducted at incrementally greater speeds to determine if and when the main driver would lift off the rail due to unbalance. The train entry speed into the test area, which consisted of greased rail, was 80 mph. When they reached a slip speed corresponding to 164 mph, the main driver lifted off the rail a fraction of an inch. The only way they could confirm this was to review the high speed movie footage. There was no damage to either the locomotive or the rail. They installed a special calibrated speedometer to confirm the rotational speed, since the wheel speedometer with a wheel mounted against the third driver to measure speed skidded during a high speed slip. The engine number is not available, but the engine, from photos, was one of the J-3A's with Scullin double disc drivers, but standard, non roller bearing, rods. The Timken roller bearing rods applied to the last five Dreyfuss engines weighed substantially less than the standard rods, so there was less weight applied for both balance and overbalance. (Overbalance was the "extra" weight applied to offset the reciprocating (i.e. back and forth) action of the small end of the main rod to reduce the tendency of locomotives used in high speed service to "nosing".)

This testing was initiated by the NYC as a result of reports of the New Haven I-5 Baldwin built Hudsons damaging rail due to dynamic augment at the speeds that NH ran, which I believe was 70 mph.

The NYC J-3a was one of the best industrial designs in the history of this country in any category you care to name.

 

One thing to keep in mind here....until recently, it was very difficult to transfer old movies at correct speed.  Most of those old films have the trains (and everything else) moving MUCH faster than it was in real life.  If it looks like it's moving too fast to be real, it's probably the transfer.

Kevin

Kevin,

 

Good point, but I don't think the footage was filmed that far back... Laurel and Hardy style.

 

The Empire State 4-4-0's rods and rigging must have been quite a sight... when it set the record; but, the big, more complex, articulated machines, they really had some steel/iron(whatever it was) flying about.

 

Rick

 

One thing I recall from my days of fooling around with home movies in the 70's, the standard silent film speed was 16 frames/second on both 8mm and 16mm film.  With the introduction Super 8mm film, the silent speed was changed to 18 frames/second to reduce jerkyness of the larger projected image.  Sound film ran at 24 frame/second in both formats.

 

Back in those days and earlier, shooting amateur movies was a somewhat expensive hobby, what with camera, film, processing and projector.  Plus many "home movie" cameras were spring driven and could only shoot around a minute or so before needing rewinding.  Even many 16mm cameras were spring driven. 

 

A battery operated camera that could shoot with sound was much more expensive. 

 

Many amateur's shot in 8mm and later Super 8.  Shooting in 16mm was something of a rarity for casual railfan. The old 8mm cameras shot on 16mm film, but only on half the frame.  You then flipped the reel or cartridge over and shot on the other half frame.  The processor would slit the film down the middle after developing and splice the two pieces together for your completed epic.

 

Amateur cameras had only about 3-4 minutes worth of film capacity in the magazine.  The better cameras shot at both silent and sound speeds, but I suspect many shot at the silent speed to get more film time.

 

Rusty

 

 

 

Some electric locomotives had side rods, too; "Big Liz" a FF1 locomotive was one of them -

 

 

http://en.wikipedia.org/wiki/PRR_FF1

 

 

With only two speed settings(10.3 and 20.6mph) the side rod action, at least the speed of LIz's moving rods, didn't compared with it's steam cousins.

 

Power-wise, the unique FF1, I read, could out-muscle a Big Boy. It's said that Liz, when pulling, would break couplers, and, when pushing... she would crush cars, ahead of her.

 

 

Rick

Re: my previous post - I was trying to provide a link for "Jack Shaft" locomotives, but, an error kept appearing. Jack Shaft's have side rods.

 

 

Rick

 

 

Ricardo,

 

That just doesn't look natural... right... at one with the universe; somethings got to give.

 

 

Rick

Gary is a new member here...just joined us a couple days ago. His name may not be familiar to many of you, but he is one of foremost steam locomotive experts in the world. 

 

Gary is a steam-qualified engineer and has run the 765 many times. He did his share of running on our trips around Horshoe Curve back in May. Gary is the guy who taught me to run the 765!

Welcome, Gary.

 

 

Rick

 

That point goes for almost ANY footage filmed before VHS or Beta.  That roughly translates to anything prior to about 1977.  This includes all 8mm, Super8 and 16mm.  You can transfer it at "correct" speed now, but the frames/second rate is different and must be compensated for.

 

Otherwise (and this goes for about 90% of all vintage railroad movies out there on the market), you are running 16fps or 24fps at 30fps--and the resulting footage is sped up accordingly.

Kevin

 

Correct me if I'm wrong, but isn't that going to increase axle loadings by a pretty decent margin?

Kevin

You are correct. It did indeed increase the axle loadings, and the C&O Rwy steam locomotives had some of the highest axle loadings in the world! How about 80,000 pound, and possibly higher, axle loadings? Even todays "modern" AC diesel electric locomotives don't even approach THAT.

The electric locomotives with side rods have frame mounted, rather than axle mounted, motors.  The big difference between side rod driven steam and electric locomotives is that the electric locomotive does not have the reciprocating piston the steam locomotive has. In the electric locomotive all the motion is rotary, which means that the imbalance can be balanced out so there is no reason there should be any dynamic argument.  

 

The two speed electric locomotive was common for early AC powered locomotives.  Synchronous or induction motors with two poles, running on 60 cycle power, want to run at about 3600 RPM and four pole motors at about 1800 RPM. The motors run at slower speeds with more poles and/or lower frequencies.  Four pole motors could be reconnected to run as two pole motors giving two speeds.  Adding more poles increase the motor diameter, so in railway service this was generally not done.  Series resistors were used to accelerate the locomotive to the synchronous speeds.  Electric railway technology in this country did not survive on railroads not owned by a government because of the cost of the overhead power distribution system. To eliminate the cost of the overhead contact system, the railroads got electric locomotives with onboard engine generators and called them diesel electric locomotives.

Fascinating topic.

 

A vehicle moving at a speed in MPH equal to the diameter of its wheels will have those wheels turning at 336 RPM.  Counterbalancing a steam locomotive had to deal with that fact, and all the forces (reciprocating and rotating) had to be calculated for the desired RPM to attain the speed the railroad wanted the engine to run.

 

In other words, an 80-inch drivered engine's drivers would be turning at 336 RPM at 80 MPH, and half again more at a speed half again as fast - in other words, 120 MPH would require 504 RPM.  5432's J3a Hudson at the  slipping speed noted would be turning up 710 RPM, a fantastic figure indicating that the locomotive was very well balanced, indeed.

 

N&W's 70-inch class J was equipped with Timken's lightweight alloy rods made in Roanoke Shop (the web of the side rods was 1/4th inch thick; the main rods 1/2 inch), and N&W's Mechanical Engineers figured the counterbalancing.  They didn't resort to disc driving wheels.  With new tires, a J running 105 MPH would be turning 504 RPM.  When J 610 was tested on the PRR (Feltonhill can tell you more about this) the PRR personnel recorded a maximum speed of 111 MPH more than once, I'm told.  They said the PRR only had one locomotive that rode better than the 610 and that was the 84-inch drivered 6-4-4-6 - the S1 "Big Engine". 

 

N&W operated steam locomotives regularly at as high driving wheel RPM as just about anyone, and was not known for slinging rods around the countryside.  I know of several failures (I've never seen that film of the A failing) and none were a result of plain old equipment failure; there was a human failure involved somewhere.  I have photos of a Y-6 2-8-8-2 that underwent a catastrophic running gear failure in 1956, but it was due to the engine not having been drifted properly.

 

The Milwaukee Road Hudson failure referred to above was due to a link failing on the lubricator that fed the crosshead guides; it wasn't a rod failure per se.  Lack of lubrication caused the right crosshead to freeze in the guide at about 90 MPH, causing all sorts of interesting things to happen.  Ted Rose's painting of the failure is one of the most remarkable examples of railroad art I've ever seen; there were no photos of the incident, of course, so Ted and I talked at great length about how it actually happened (the ICC failure report is not quite accurate) and he just flat nailed it.

 

One would think that it would be a piece of cake to counterbalance a high-drivered steam locomotive for 336 RPM, but for exceptions I give you the Atlantic Coast Line 4-8-4s which were intended for fast passenger service but were never able to be run at the speeds required.  Western Maryland's Challengers and Northerns reportedly had the same problems.  All of these were Baldwin engines, BTW, for what its worth.

 

EdKing

You guys are serving up some quality information; thanks for the donations.

 

 

Rick

I have a DVD that has that footage of the A dropping that side rod.  I believe what happened was that the cross head guide dropped and that happened right in front of the man that was filming it.  And then later on you see the rod has been removed and the A continued on.

Chris