Steam locomotive driver wheels: questions and discussion of quartering, lead, axles, wheels, tires, rods etc

I think the answer to #4 is magnesium, which would have been in high demand for aircraft construction during WW2:

https://en.wikipedia.org/wiki/Magnesium

Historically, magnesium was one of the main aerospace construction metals and was used for German military aircraft as early as World War I and extensively for German aircraft in World War II.

Wright Aeronautical used a magnesium crankcase in the WWII-era Wright Duplex Cyclone aviation engine ...

Titanium came into industrial use later, generally in the 1950's.

Great questions.  Yes, giant Woodruff keys can be found on locomotive axles.  Yes, tires can slip.  SP had a patent on little clips to keep the tire from leaving the wheel.  Do not know on the rods - I think they were aluminum.

I forget which way the quarter goes - but the poster is correct; PRR is opposite everybody else.  And duplex or otherwise, inside rods would be way too complex. Now we would just control it with a computer.  I suspect two pairs of cylinders on the same rods would quickly result in breaking something.

Questions #3

Why didn't the Pennsy duplex-drive locomotives use inside connecting rods to connect the front and rear engines, to eliminate the slipping problems?...

I'm supposing the mid-frame cylinder saddle was too bulky to allow the possibility of inside connecting rods between the first and second sets of drivers. But I can't find any good photos of stripped-down duplex locomotive frames to clearly illustrate that. How about a chain drive?

bob2 posted:

Great questions.  Yes, giant Woodruff keys can be found on locomotive axles.  Yes, tires can slip.  SP had a patent on little clips to keep the tire from leaving the wheel.  Do not know on the rods - I think they were aluminum.

Nope. No aluminum rods EVER on operating steam locomotives.

I forget which way the quarter goes - but the poster is correct; PRR is opposite everybody else.  And duplex or otherwise, inside rods would be way too complex. Now we would just control it with a computer.  I suspect two pairs of cylinders on the same rods would quickly result in breaking something.

PRR used left hand (fireman side) lead. Most others were right hand lead for quartering.

In the case of N&W's J's The rods were originally made in Roanoke, forged in the Smith Shop, I believe there is a company film showing this.  Later on because of a crank pin failure the rods were redesigned and Timkens High Dynamic Steel was used.  The 600,605,610 and the 611 got these new rods...today the 611 is carrying rods made by Timken.  And as such no longer has her intermediate rods.

Timken also provided the High strength, Light Weight rods and roller bearing configurations for the Santa Fe 2900 class 4-8-4s and the famous PRR T1 class 4-4-4-4 duplex locomotives.

There is a wealth of information in the Locomotive Cyclopedia 1941 and 1944 books, which should answer most all of anyones questions.

Hot Water posted:

bob2 posted:

Great questions.  Yes, giant Woodruff keys can be found on locomotive axles.  Yes, tires can slip.  SP had a patent on little clips to keep the tire from leaving the wheel.  Do not know on the rods - I think they were aluminum.

Nope. No aluminum rods EVER on operating steam locomotives.

I forget which way the quarter goes - but the poster is correct; PRR is opposite everybody else.  And duplex or otherwise, inside rods would be way too complex. Now we would just control it with a computer.  I suspect two pairs of cylinders on the same rods would quickly result in breaking something.

 

Correct - Due to galvanic corrosion - Aluminum and Steel do not like each other, Magnesium is even worse!

I was doing some light reading and the Northern Pacific locomotives had  issues with boilers with steam leaks due to metal fatigue. At the time just before WWII there were experiments using a lighter Alloy of steel that was stronger as well. It had elements of Silicon in the steel. These were going to replace boilers on their Z6-Z8 challengers. Unfortunately by the time they were delivered after the War the NP started the their shift to FT and F3 motive powered units and the boilers were used for Hi-way drainage ditches... !

J Daddy posted:

Hot Water posted:

 

Nope. No aluminum rods EVER on operating steam locomotives. 

Correct - Due to galvanic corrosion - Aluminum and Steel do not like each other, Magnesium is even worse! ... 

What does galvanic corrosion have to do with metals used in rods on a steam locomotive ???

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,in the presence of an electrolyte.

Ace posted:

J Daddy posted:

Hot Water posted:

 

Nope. No aluminum rods EVER on operating steam locomotives. 

Correct - Due to galvanic corrosion - Aluminum and Steel do not like each other, Magnesium is even worse! ... 

What does galvanic corrosion have to do with metals used in rods on a steam locomotive ???

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,in the presence of an electrolyte.

So,,,,,you saying that Galvanic Corrosion occurs ONLY when there is electricity present?

Besides, aluminum was not used for steam locomotive rods, because it wasn't strong enough! Back in the 1930s and 1940s, they had not developed aluminum alloys to the extreme strengths we know today.

Ace posted:

J Daddy posted:

Hot Water posted:

 

Nope. No aluminum rods EVER on operating steam locomotives. 

Correct - Due to galvanic corrosion - Aluminum and Steel do not like each other, Magnesium is even worse! ... 

What does galvanic corrosion have to do with metals used in rods on a steam locomotive ???

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,in the presence of an electrolyte.

For design and engineering, the use of metals that interact in galvanic environment are usually avoided due to high cost in insulating them. If they interface and make contact dynamically. The material can fail prematurely...thus Aluminum and magnesium alloys are found in these in environments with steel but it is very expensive and very rare...

This is provided that the Aluminum and Magnesium would be a good substitute for the higher strength of steel...

Hot will have to forgive me - I was just remembering a long-ago memorized page in Staufer's Pennsy Power.  See page 67 - "Experimental aluminum side rods applied to I1s 4375".  It goes on to say they were too brittle, and lightweight steel alloy was later used.

Hot Water posted:

Ace posted:

J Daddy posted:

Hot Water posted:

 

Nope. No aluminum rods EVER on operating steam locomotives. 

Correct - Due to galvanic corrosion - Aluminum and Steel do not like each other, Magnesium is even worse! ... 

What does galvanic corrosion have to do with metals used in rods on a steam locomotive ???

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,in the presence of an electrolyte.

So,,,,,you saying that Galvanic Corrosion occurs ONLY when there is electricity present?

ABSOLUTELY NOT! Galvanic Corrosion never stops!

Besides, aluminum was not used for steam locomotive rods, because it wasn't strong enough! Back in the 1930s and 1940s, they had not developed aluminum alloys to the extreme strengths we know today.

Actually Aluminum has very good strength properties its the fatigue and stiffness issues that sell it short...

Hot Water posted:

So,,,,,you saying that Galvanic Corrosion occurs ONLY when there is electricity present?

I'm saying it wouldn't be a significant issue with regards to rods on a steam locomotive because it's not a significant "galvanic environment" with extensive electrolytic factors.

Besides, aluminum was not used for steam locomotive rods, because it wasn't strong enough! Back in the 1930s and 1940s, they had not developed aluminum alloys to the extreme strengths we know today.

I accept your explanation that aluminum isn't practical for rods on basis of STRENGTH - not because of galvanic corrosion issues.

J Daddy posted:

For design and engineering, the use of metals that interact in galvanic environment are usually avoided due to high cost in insulating them. If they interface and make contact dynamically. The material can fail prematurely...thus Aluminum and magnesium alloys are found in these in environments with steel but it is very expensive and very rare...

This is provided that the Aluminum and Magnesium would be a good substitute for the higher strength of steel...

Lots of machines use different metals for different components in contact with each other. It's not a significantly "galvanic environment" bathed in corrosion-enabling electrolytes.

"Lots of machines use different metals for different components in contact with each other. It's not a significantly "galvanic environment" bathed in corrosion-enabling electrolytes."

Not machines exposed to the elements!  True Aluminum has roughly a 1/3 the strength  the properties of steel, however with physical cross sectional strength this can be made up for... the true down fall of mixing metal materials is how they oxidize in a climatic environment.

If you have Al antennas in the Houston area, you better put a coat of clear coating on them, or else they will pit.  Was heat and humidity a consideration in not using more Al products in the railroad environment?

Plus, there were some mostly Al boxcars built after WWII.  They did not last very long, it seems.

As to question 4, the metal they may not have been able to get during WWII could have been vanadium. Used in alloy steels, I believe the primary source is from Russia. 

You will not find a machine more exposed to the elements than a modern airliner.  Aluminum skin, steel bolts, plastic cowls and control surfaces, copper wire, lots of exotic materials used in forgings . . . Only boats and ships really have galvanic problems when in service.

One of my airplanes has wood wing spars, aluminum ribs, steel attachment fittings, brass coated steel nails holding the ribs to the spars, and drain holes in the trailing edges to let residual moisture out.  So far, so good.

"You will not find a machine more exposed to the elements than a modern airliner.  Aluminum skin, steel bolts, plastic cowls and control surfaces, copper wire, lots of exotic materials used in forgings . . . Only boats and ships really have galvanic problems when in service."

Remind me not to fly on your plane. If you mix steel and aluminum fasteners on structural elements on airplanes ... that is one doomed airplane... If you look real close on the wings and fuselage as you fly you sill see the use of Henrobs, which are self piercing aluminum rivets. They join the aluminum panels and seal the outside elements from corrosion / oxidation. Yes steel bolts are used in some areas, but they have galvanic protection coatings to prevent metal to metal contact. And are not in a dynamic environment rubbing on each other....

You also forgot to mention military vehicles, Aerospace, Heavy Truck and Heavy Equipment, Automotive all spend millions of dollars developing, designing, and validating the interface of metal alloys, albeit welding and fastening interfaces in the event of galvanic corrosion.

Ace posted:

What does galvanic corrosion have to do with metals used in rods on a steam locomotive ???

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,in the presence of an electrolyte.

All you need is two dissimilar metals and some moisture with impurities in it to create a battery. Aluminum in contact with steel where rain water can intrude is a classic example.

The rod material used by Timken for "lightweight rods" as used on NYC Niagaras, N&W J's, ATSF 2900's, six NYC Hudsons, 5 N&W "A"'s, 5 C&O Greenbriers, and a few other locomotives (like the UP streamlined 4-8-2's) were made of manganese vanadium steel. Timken may have made only the forging, with final machining by either a loco manufacturer or RR vendor. Aluminum is too brittle to use for main and side rods, and PRR should have realized that. Timken lightweight rods are very strong, especially considering their relatively small cross sectional area, but precautions must be taken so the rods are not "knicked". I understand that in the steam age most RR's handled these rods using canvas. I don't believe it is a coincidence that the locomotives identified above with Timken rods are all among the most highly regarded.

Heres a "fun" example found at a "kids restaurant" since I'm no chemist or alloy expert.

   The water race has a water gun and large squirt guns. The guns are aluminum, the tubs stainless steel. They don't touch. The water flow alone makes enough connection to cause the stainless tubs to crack without much vibration, over as soon as a year if distilled water isn't used to prolong the tubs life! It should be changed weekly and mine lasted for many, many years that way, but I saw plenty of other fail with tap water. There is no current, all pieces connect with hose, no contact till the system pressurizes,(pump to gun) and fires(gun to target) then drips to the tank below. Very Little is a direct flow from gun to tank. The target carries extremely minimal dc voltage and current polarity didn't matter when it came to failing.

You'd think the aluminum would be the metal with the issue, but it's not always the case, both can fail. 

  When discussing the issue, airplanes were my first thought. I was told the metals were coated then.

  Engines using aluminum rods etc were my next question. Nobody could answer......but the tubs crack, so I just accepted it as a fact, always considered it, and moved on. Aluminum tanks were an option but they were hard to keep clean, & easy to destroy.

Semi related, the old air cooled VW block was an Alum/,Mag alloy. More aluminum to pure aluminum was used in later versions to make the cases more repairable, less brittle, and not have unstoppable Mag. fires. It will burn as a fuel if it gets hot enough. I don't think water puts it out either.??

You'll find unusual pitting inside on both steel and blocks of very old and original VW engines that sat idle for decades. I never saw that in an all steel engine.

My GUESS on motors, etc. is the stainless alloy is less reliable than forged steel in these conditions, but the issue does remain. Oil films help discourage contact..??

Adriatic, I suspect that a lot of the problems with the stainless tanks in the water game is that it is suffering from Chloride Stress Corrosion Cracking... the fact that you saw failures in others using tap water (which is typically chlorinated if it comes from a municipality or water district) is a big clue.  This is one reason that ASME specifically forbids stainless steel in the use of power boiler construction; it is too difficult to ensure that a boiler will never receive chlorinated makeup water, or perhaps even hydro tested with chlorinated water.  "Stainless Steel" is a bit of a misnomer anyway; while it may not rust like a typical grade of steel, it is subject to corrosion given the right conditions and exposure to certain chemicals (such as chlorine).

As to the use of aluminum in steam locomotive connecting and side rods, the properties of aluminum don't lend itself to being used in such a high stress, demanding application that requires long-term durability.  Although aluminum is sometimes used for connecting rods in high performance internal combustion engines, those are almost always in service where absolute performance is first, and longevity is secondary (i.e. racing).  Edit - another aluminum con rod application is in small, very low stress engines (i.e. push mowers).  The vast majority of IC engines continue to use rods made of ferrous materials, or perhaps titanium.  I mention this because it is an interesting parallel to steam locomotive rods; but the rods on a locomotive are subject to stresses that are many, many magnitudes over that in most IC engines, and locomotive rods are one of those things that should ideally never fail in service.  The choice of most steam locomotive designers to stick with steel as the material of choice for side and connecting rods reflects the ability of steel to cope with the intense compression and tension forces (as well as the bending forces exerted by centrifugal force at high speeds) that the rods are being cycled through hundreds of times each minute.  Steel is much more forgiving than aluminum when it comes to fatigue from cyclical stresses, as J Daddy pointed out.  From what I can tell, that would be the primary reason that designers continued to use steel for locomotive rods instead of aluminum; any concern about galvanic corrosion would be secondary, although that was apparently so far down the list as to not even be a worry.

I think it is worth noting that in "The Steam Locomotive" - a book on steam locomotive design written by Baldwin's Chief engineer, Ralph Johnson in 1942 - there wasn't any mention of non-ferrous materials for locomotive rods in the section on counterbalancing.  In fact, this is the only mention of rod material choice in the book:

"For the maximum reduction dynamic augment every effort should be made to make the revolving and reciprocating parts as light as possible, consistent with strength requirements.  Advantage should be taken of improved design and high quality alloy steels to keep the weights of these parts to a minimum."

Also interesting, is this mention of track damage during slip testing of steam locomotives:

"Also it was noted that a preponderance of damage occurred on the right side.  This is difficult to explain, but may be due to the right hand crank leading, or to the softer shoulder on the outside of the track."

The lends some credence to the story referenced by Ace in Question #2.

Interesting discussion!

I believe some of the engines delivered during the war had huge rods due to the lack of good steel alloys being available. These better alloys were being used in machines of War and hence in short supply. Once the war was over then the RR's replaced rods with lightweight alloy rods, some with roller bearings. Pretty sure I've seen pictures of some J's and 2900s with heavy rods.

Just a couple of disconnected thoughts to throw in here. 1)  Galvanic corrosion is a BIG problem in the trucking industry, especially if those trucks run in areas where road salt is used.  Big aluminum brackets can "melt down" until there is almost nothing left, and just about any fastener that contacts aluminum and steel will be nearly impossible to remove after a few years.  2) Even if an aluminum side rod were practical strength wise, it would likely have to be SO BIG to get the proper durability that it's size would be impractical.  Aluminum connecting rods in most American V-8s barely fit in the engine block, and are generally used only in applications like drag racing where they are asked to run VERY LITTLE.  As an aside, the top of the line Corvette engines have now moved on from Forged steel and then powdered metal to titanium.  3) Timken produces FANTASTIC steel alloys, probably on par with the best material made in this country or anywhere else in the world.  That is one of the reasons Timken bearings are so good, they start with better material than most of their competitors and go from there. I believe they made the first vanadium steel ever produced in the US, for Henry Ford circa 1905.  Magnesium is VERY flammable (and expensive) to the point that most racing sanctioning bodies outlaw its use in major components. Magnesium wheels can catch fire just from frictional contact with a concrete retaining wall.  Stainless steel can be a very tricky material, and lacking in some respects.  For instance, stainless fasteners tend not to be very strong, and relatively easy to snap in two.

The 1938 Loco Cyc has an advertisement on p. 603 by Alcoa. It shows an Alton and Southern 0-10-0 #14 with "aluminum rods and motion work" that "has been giving satisfactory service for over six years of operation". With low speeds and low mileage, I regard this as a non critical application. So PRR might not have been the first. I do not know how long #14 lasted...but suffice to say that aluminum rods were not widely used.

Hudson5432 posted:

The 1938 Loco Cyc has an advertisement on p. 603 by Alcoa. It shows an Alton and Southern 0-10-0 #14 with "aluminum rods and motion work" that "has been giving satisfactory service for over six years of operation". With low speeds and low mileage, I regard this as a non critical application. So PRR might not have been the first. I do not know how long #14 lasted...but suffice to say that aluminum rods were not widely used.

Interesting. The Alton & Southern was owned by Alcoa (up to 1968) and apparently the #14 was built with various aluminum parts as a demo project.

http://www.steamlocomotive.com/0-10-0/?page=as

... Alcoa's interest in promoting aluminum for load-bearing applications led to the specification of aluminum in many components from grab irons to side rods.

Back to airplanes for just a second - my aircraft is not the only one with steel fasteners holding aluminum together.  I am not well versed in how Boeing puts airplanes together, but without steel fasteners in, say, a King Air spar, you would not be airborne for long.  Piston engines have cast aluminum cases held together with steel nuts and bolts, in almost all cases right through the giant Constellation engines.