Looking at the cylinders on some foreign steam locomtives, on the front end of the valve and piston cylinder theres a rod sticking out from the center. Why did they build them like this?
Im assuming its the piston and valve rod.

adofmsu@aol.com

Lots of American engines had these, too, up until about 1912 or so. These were tubes to carry an extension of the piston rod. I presume the purpose was to carry the piston on a rod that was supported at the rear by the crosshead and at the front by the rod extension, so that the weight of the piston did not bear on the cylinder bore and wear it out-of-round. My guess would be that these fell out of use when designers and maintainers discovered that it cost more to keep all these bearing surfaces aligned than it did to bore out or resleeve the cylinder bores occasonally. Lots of engines built with extensions lost them during rebuilds, so there are only a few preserved engines with these intact, none of which I can think of now.

Aarne H. Frobom
The Steam Railroading Institute
P. O. Box 665
Owosso, MI 48867-0665

froboma@mdot.state.mi.us

These are called tail rods. They were very common in large stationary steam power. Basically with a tail rod both ends of a piston rod were supported independently of the cylinder, so the only pressure on the cylinder wall is that of the piston rings. This greatly reduced wear of the cylinder wall. With large stationary steam engines, such as the 68" diameter piston of our Tod engine, which easily weighs a couple of tons, that weight bearing down on the cylinder wall would wear it out in short order.

The european practice of using tail rods on locomotives helped to prolong the life of their locomotives. In the US we didn't have time to bother with such frills, we as a nation were too busy laying tracks down every nook and cranny of the countryside. However, some early locomotives, like the first PRR K4, the 1737, had tail rods when built.

The photo is of the tail rod on our 34" high pressure cylinder.

The Tod Engine

todengine@woh.rr.com

Spokane, Portand & Seattle (SP&S) #539 (built as
NP W3 class #1762) in storage at Battleground WA
has 'em.

You can just make the rods out in the photo below
where they break the line of the painted rim of
the leading truck.



Washington Steam Railroads and Locomotives

brianfr@speakeasy.org

That's a pretty little Mike. I hope she's being better cared for now.


kevingillespie@usa.net

Is that a potted plant hanging from the headlight bracket?

The Tod Engine
todengine@woh.rr.com

Extended piston rods may be one of those items we shouldn't have thrown out. It may be that they weren't worthwhile given the technology of the ~1910's but by the 40's they may have been worth another look.

A lot of foreign steamers retained them until the end of steam. David Wardale designed new pistons with extended piston rods for the "Red Devil" (SAR Class 26 4-8-4 #3450) but unfortunately they were never manufactured. He felt these would be one item that would help bring steam cylinder wear rates into the range of diesel engine practice. Other items which were fitted to the Red Devil which helped dramatically with the wear rates were high-chromium content cast iron cylinder liners, multiple narrow piston rings (as opposed to few wide ones), and a layer of bronze welded onto the outer diameter of the pistons.

The ACE 3000 also would have included extended piston rods.

Good Steaming,
Hugh Odom

The Ultimate Steam Page
whodom@awod.com

> Kevin Gillespie said: That's a pretty little Mike. I hope she's being better cared for now.

Not sure what you're driving at. If it weren't for the folks at the Lewis and Clark RR, the 539 (one of two surviving SP&S steam locomotives) would have been cut up for scrap by the City of Vancouver WA. They're trying to raise funds for it's restoration. I can put you in touch if you'd like to make a donation.

> Is that a potted plant hanging from the headlight bracket?

Yep, and more on the pilot deck and in the cab windows. The local garden club was having a show and apparently decided to dress the engine up.


Washington Steam Railroads and Locomotives
brianfr@speakeasy.or

> Not sure what you're driving at. If it
> weren't for the folks at the Lewis and Clark
> RR, the 539 (one of two surviving SP&S
> steam locomotives) would have been cut up
> for scrap by the City of Vancouver WA.

I'm just saying that I'm sorry she was allowed to become a rusting eyesore before the folks at Lewis and Clark rescued her. If I hit the lottery, count on a donation, althought there are several engines in this category a little closer to Maryland that I would like to help. I just wish more communities would appreciate the history and heritage of their "park engines." To have the city fathers want to destroy a steam locomotive this late into the preservation is a massive show of gross ignorance on their part.

As for the potted plants, I'll put up with them as long as people will look at the engine, and perhaps put a couple of dollars up for her care.

kevingillespie@usa.net

> I can put you in touch if you'd
> like to make a donation.

Please send contact info. If there's a website describing the project, send that as well, or if there's some official writeup about the 539 restoration. Thanks.

hi_plain@yahoo.com