> We have just completed two new main rods,
> and a new piston rod, as well as
> modifications to one piston, and repairs to
> one combination lever for the Western
> Maryland #734.

> The original main rods for #734 were of the
> strap and split brass big end style, which
> had been modified into a floating bushing
> big end style by bolting new big ends onto
> the rods. One of these new big ends broke
> several years ago resulting in serious
> damage to the machinery on that side. The
> engine has been running since then with
> parts on loan from the Illinois Railroad
> Museum.

> Dan Pluta from the Western Maryland
> contacted us last year to see about repair
> or replacement of the damaged parts so those
> borrowed from Illinois could be returned.
> Stress analysis revealed that the area where
> the new big end broke was a weak design, and
> exceeded the stress limits covered in the
> Baldwin Standard Practice, breaking right
> where Baldwin said it would.

> We agreed that new rods of one piece design
> would be the surest route to avoiding
> another failure. In order to ovoid
> disturbing the counterbalance of the engine,
> Dan specified that the new rods have the
> same weight and center of gravity as the old
> ones. Since one piece rods are more
> efficient than built up rods, this meant
> that we had to add about 200 pounds of steel
> to the basic design in order to make these
> weigh as much as the old ones, about 1100
> pounds each. We use a CAD program in design
> work, which can forecast the weight of any
> odd shaped part to within 0.5%. We used a
> big end design in the 1930 Locomotive
> Cyclopedia as a basis for the new big end
> design, with the extra metal around the
> grease fitting adding needed weight.

> They measure 141" long x 18" tall
> x 5" thick. 1045 steel was specified,
> and delivered by the steel supplier already
> annealed, and ultrasonically tested for
> internal flaws.

> There is a machine shop nearby equipped with
> a CNC mill large enough to machine the
> entire length of these rods in one setup. We
> contacted them, and they quoted a reasonable
> price, completing the machine work in about
> one month.

> Back at Strasburg, we drilled the holes for
> the grease fittings, and pressed in the iron
> outer bushings for the big ends. We made a
> new piston rod (the old one was bent), with
> some modifications in the crosshead and
> piston fits, where calculations had shown
> some weakness in the old design. A new
> piston rod key was also made. We then
> modified the old piston to WMSR specs for a
> different design of piston rings, and
> mounted it on the new rod.

> See more pics at
> http://www.strasburgrailroad.com/wmsr/

We're looking forward to getting the loaner parts back for our LS&I Consolidation! Now, if you would care to make NEW ones for us too . . .


Kevinmccabe@Avenew.com

> Kelly,
> I may be making a pair of eccentric rods
> from stock bar or plate in the near future.
> Could 1045 plate be used in place of 4140
> annealed bar for rods? How does 1045 cut
> compared to 4140. 4140 tends to be
> "stringy" and unless the cutters
> are sharp, the material tears and smears.
> Thanks.

> Bruce

Hi Bruce:

I would recommend using the 1045 steel because the modulus of elasticity for all the steels is 30,000,000. This means your parts are going to strain the same for a given stress and part geometry regardless of the material. 4140 and 4340 can only be machined in a tempered condition and they typically are used in highly stressed parts like piston rods where toughness and fatigue resistance are critical. Eccentric rods that follow the usual geometry are not considered critical elements in my mind.

When I worked at Skinner Engine Company in Erie, PA years ago they used 4140/4340 on piston rods and called out 1045 on massive forged crankshafts for the reasons I gave above.

Also, thank you Kelly for posting your descriptions about the WM main rod project. Those who operate old machinery should pay special attention to materials and processes like the Strasburg has. There have been many improvements since the days of steam and careful attention to form and function relative to available materials and processes is a key path to maintaining, and in many cases improving, the operational reliablity of old locomotives.

Bill Petitjean

petitinc@nwlink.com

> That is why the alloy steel 1045 was
> specified, and also why it was delivered
> preannealed and non destructive tested.
> Kelly can problably give you the exact delta
> between old Baldwin spec forgings and the
> annealed 1045, but I suspect the 1045 is
> more than equivalent in strength.

> Steve Zuiderveen hello steve look at your spec.book 1045 is a mid. carbon steel and is not an alloy. It is however most likly what the first rod was made of. 1040-1045 is also used for pins and axels. regards bb

staybolt2@netscape.net

#31, and #475 are in service, with #475 running at this time. #90 is getting about 75 new flexi sleeves, bolts and caps, new front corners in the firebox, and extensive repairs to her tender, as well as the usual annual work. #89 is getting a basic annual. #972 contiues to wait behind the shop, as she will continue to do until an upturn in business requires her services.

The parlor car and dining car both received new Stadco generators this winter. The PRR box car completed overhaul this winter. The restoration of the Western Maryland coach recently swapped from the RRMPA is proceeding very slowly, but won't be finished this year. Several other coaches are cycling through the shop for minor work.