I'm looking for suggestions as to the best material to use in the fabrication of new drive rods for our locomotive. Anyone out there have a recommendation for type of metal/alloy and manufacturer?

Thanks,
Allen

What is your locomotive? A mainline 4-8-4 or an 0-4-0 teakettle? I am sure you could find metal specs. for locomotives of similar size and use that material.

You may want to have your existing side rods spectrographically tested to determine the composition of the metal.

Tod Engine Foundation
rick@todengine.org

Interesting question. Never had to make new rods.

It seems to me you don't want anything too hard and brittle - maybe about 1038 or 1040?

Anybody out there speced this out before?

Dave

irondave@bellsouth.net

> Interesting question. Never had to make new
> rods.

> It seems to me you don't want anything too
> hard and brittle - maybe about 1038 or 1040?

> Anybody out there speced this out before?

> Dave

Dave ( and others )

The designing and manufacturing of new drive rods is a straightforward engineering design problem.

To design these parts would include the following analyses:

1) Evaluation of dynamic loads

2) Superpositioning of loads from the steam cylinders due to the steam pressure on the pistons.

3) Fatigue analysis

4) Evaluation of buckling strength

5) Evaluation of tensile loads

6) Evaluation of dynamic balancing

The process would be iterative, as the strength and fatigue properties of the material will affect the size of the part and therefor the weight of the part. This in turn will affect the dynamic loadings.

Alternatively, if you have an old part, a sample can be analyzed to determine the composition. Once the composition is known, similar alloys can be selected. The new part can then be made based upon the dimensions of the old parts if they exist.

Hope this helps.

P.Kurilecz


pkurilecz@yahoo.com

The locomotive is an 0-4-0 "teakettle". We have the existing rods. One of them has A LOT of pitting and corrosion, so we thought it would be prudent to have a pair of new rods made. Seems to be the result of the blowdown being located in the path of the rod. It will obviously be re-directed. We would like to use a better grade metal than what the rods are made of now, so we're looking for suggestions.

Thanks,
Allen

> Interesting question. Never had to make new
> rods.

> It seems to me you don't want anything too
> hard and brittle - maybe about 1038 or 1040?

> Anybody out there speced this out before?

> Dave

The Baldwin Locomotive Works Standard Practice specifies 80,000 lb. tensile strength, 40,000 yield (when annealed) steel (AAR M-102-42 Grade 3) in their rod calculations, with a note, that steel of different tensile strength may be used by raising, or lowering the stress values in proportion. You can “run the numbers” on your present rods to see what the present rod stresses are, and determine from there, how strong of a steel that you need. In many cases, the rods were quite over-designed, and a lower tensile strength steel can be used with confidence. Generally, you want to make any new rods the same physical size as the old ones, so there is no change in counterbalance. You can take chips from your present rods to a testing lab for a chemical analysis, and if your present rods are scrap, you can cut a piece out for a tensile test as well.

The M-102-42 Grade 3 spec. says: Carbon 0.40-0.55%, Manganese 0.60-0.90%, Phosphorus 0.045% max, Sulfur 0.05% max. This chemistry fits 1042 steel. 1140, 4042, 4142, and 5145 are all in the ballpark, but have other alloying elements in them that may raise questions. There is also the question of availability of specific alloys in specific sizes, especially in small quantities.

All of the calculations are on just a few pages of the Standard Practice, and can be done by anyone with average algebra skills. There are copies out there, and if I understand correctly, Little River sells reprints.

As far as a manufacturer, the Strasburg Rail Road has designed and built rods for the Lyon reproduction locomotive, and for the ThomasÂ’ they are building.

> I'm looking for suggestions as to the best
> material to use in the fabrication of new
> drive rods for our locomotive. Anyone out
> there have a recommendation for type of
> metal/alloy and manufacturer?

> Thanks,
> Allen

Allen,

One good place to check would be with the "Duke of Gloucester" group and the "A-1 Trust" group in England. The Duke is a poppet valve equipped 4-6-2 that was restored in the 1980's. A complete set of rods and poppet valve cylinders was fabricated for the Duke. The A-1 is a post-WWII 4-6-2 design being built from scratch, and it's about 70% complete at present, basically lacking only a boiler. The rods for it were completed fairly recently and are shown during fabrication on their website.

The Duke's website is:
http://www.dukeofgloucester.cwc.net/

The A-1 trust's website is:
http://www.ambler.plus.com/index2.htm

Both of these groups should be able to recommend rod fabricators to you.

Good Steaming,
Hugh Odom


The Ultimate Steam Page
whodom@awod.com

Hi Allen;

Weld up any truly deep pitting and grind smooth. Polish the rods and keep them clean. Don't sweat it.

How much train are you pulling how far on what track?

Dave

irondave@bellsouth.net

> Hi Allen;

> Weld up any truly deep pitting and grind
> smooth. Polish the rods and keep them clean.
> Don't sweat it.

Please keep in mind that high carbon steel can't be casually welded. If you don't know the carbon content, you must assume that it is high carbon steel. Also there are the feds to keep happy.

§230.96 Main, side, and valve motion rods.

(a) General. Main, side or valve motion rods developing cracks or becoming otherwise defective shall be removed from service immediately and repaired or renewed.

(b) Repairs. Repairs, and welding of main, side or valve motion rods shall be made in accordance with an accepted national standard. The steam locomotive owner and/or operator shall submit a written request for approval to the FRA Regional Administrator prior to welding defective main rods, side rods, and valve gear components.

> Please keep in mind that high carbon steel
> can't be casually welded. If you don't know
> the carbon content, you must assume that it
> is high carbon steel. Also there are the
> feds to keep happy.

Sorry, I was assuming this was an insular operation. And it would be the odd rod on a saddletank that was high carbon steel. I would assume medium myself.

I heard several years ago about a proposal to build rods of carbon fiber. The lightness would make heavy counterweights unnecessary. Has any additional work been done along these lines?

Dave


irondave@bellsouth.net

It may well be an insular operation, and thatÂ’s fine. But there may be people who read these posts who donÂ’t have insular operations, and still want to know what to do. I donÂ’t want somebody to get into trouble for thinking that what may work for another operation with different perimeters will work for them.

As far as the carbon content of the steel, the spec. I quoted is the only one listed in the Baldwin and AAR standards, regardless of the size of engine. Sure, if itÂ’s an old one, it may have low carbon steel rods. Heck, they may even be wrought iron. But regardless of how good of a welder you may be, if you donÂ’t know what it is, then you donÂ’t know how to weld it.

All this is based on my belief that in this day and age, that this industry can no longer afford the casual standards of repair and maintenance that some have used in the past, in areas that need to be done right. The cost of some chemical testing is nothing compared to the cost of a broken rod end sticking out of the bottom of a boiler.

Connected or Insular, FRA or non-FRA, Be safe and do the job in a professional manner. Short cuts in action and material can result in injury and damage. And injury and damage is what we all need to work at avoiding.

Be safe.

Brian Norden

bnorden@gateway.net

> It may well be an insular operation, and
> thatÂ’s fine. But there may be people who
> read these posts who donÂ’t have insular
> operations, and still want to know what to
> do. I donÂ’t want somebody to get into
> trouble for thinking that what may work for
> another operation with different perimeters
> will work for them.

You make an excellent point. I had my blinders on on this one.

Dave

irondave@bellsouth.net

I recall the late Stan Matthews (Shop Services, Mt. Pleasant, IA) made some new rods for one of the Disneyland 4-4-0s a few years ago. He told me they were simply milled out of steel stock and not forged. Anyone know how those rods worked out?

bobyar2001@yahoo.com

Glover Machine Works (being a foundry) cast theirs out of steel. I like the mill it out idea better. Cut it out automatically from bar stock and mill in any required fluting or machined areas.

Dave

irondave@bellsouth.net