Shay 100th birthday party

[Dan Rowe]

Chris, I made a bad assumption because I am a trained Marine Engineer, and on ships, there has to be a way to isolate the superheater for warming up, and for the worst case, a superheater tube lets go. The boiler has to be shut down for that type of repair, and that is not convenient at times.

Back to Shays, the superheater loop is simple to describe. Saturated steam leaves the steam dome like usual, but not with an external steam pipe. On a Shay without superheat, the saturated steam line is visible, and it goes from the steam dome to the cab and the throttle valve on the backhead to the steam engine.

So with superheat, saturated steam goes to the smoke box and is connected without a valve to the superheater tubes. A superheater tube makes a loop inside a flue tube from the smoke box to the fire box and back. The size of a regular boiler tube is usually 2", and a flue tube is about 5" to fit a superheater loop. There will be several flue tubes with superheater tubes, and a lot more boiler tubes.
There is a manifold to supply the superheater inlet and one at the outlet that is attached to the throttle valve. The throttle valve is operated by the throttle lever or Johnson bar on the backhead with a rod that connects the lever to the valve. This detail is also internal to the boiler. Superheated steam now leaves the throttle valve in the smoke box and goes to the steam engine. This is the line with the valve.

That valve is not normal and had to be a special order. I was assuming that it could be used while the locomotive was moving down the road, which would require a superheater bypass valve. Well, there is not a superheater bypass valve. I can only guess as to why that valve is there on a factory photo. Someone wanted it for some reason it was not needed.

The Shay in Cadillac MI, shop number 549 has a steam stop valve on the saturated steam line. It did not leave the loco works with this valve. My guess is a leaky throttle valve, and for some reason, it was simpler to add a stop valve than to fix the throttle valve.

Good question, Chris. I hope my answer is helps.
On the ships, we had to work fast with no books at times. I was lucky, and we never hit a bridge. The engine room does not have a window, so I do not know how close the bridges were. My job was to keep the screw turning and the lights on.

[crueby]

Great  description  Dan, thanks!   The only ships I have been  on was day cruises on the Sabino in Mystic Seaport and the Liberty Ship in Baltimore,  the year before that container ship brought down the bridge.


Sounds like superheaters were not at all common on the Shays. Could it have been for a location with little access to water during the trip? Thats assuming the extra expansion of the hotter steam give greater range?


Thanks!
Chris

[CI]

Superheaters are about efficiencty.
Boiling water is 212 F, and that is as hot as it will ever get.
A superheater allows the steam to absorb heat that would otherwise go out the smokestack and be wasted.
Steam temperatures are not limited to 212 F.
Superheated steam can reach extraordinary temperatuers, and you don't want to inadvertantly come into contact with it, especially when it is under high pressure.

Superheat = less coal or wood burned for the same amount of work done.

I think locomotives did not have condensers, ie: there was no recovery of water from the used steam; probably for practical purposes.

.

[Dan Rowe]

Lima was not really interested in superheaters for Shays. The cost for new tooling for the smoke box and fire box tube sheets and other parts might have been thought to be worth the effort. The west coast loggers wanted superheaters and all weather steel cabs, which were not standard but available for extra cost. The Willametet Iron Works in Portland OR, made all sorts of things for logging and steam skidders, donkeys, and yard loaders. They had rebuilt a few Shays that were wrecks when they came in. Most of the Shay patents had expired, so they set up to make Shay clones. They made 23 Willamettes. Lima countered with the 3PC13 Shay. It had the features the loggers were looking for, and 24 were sold.

Superheaters, yes, more efficiency, so less fuel. In theory, the same amount of fuel and water will get you further with more efficiency. Lots of locomotive tests were done to prove theories.
More heat or energy is loaded into the steam, so more power and tractive effort. In the tractive effort formula, the factor for saturated steam is 0.75, and for superheated steam, the factor is 0.85, yielding a greater tractive effort with superheat.

The only steam locomotives I have ever heard of that had condensers were in Australia. There is no water in the western desert, so a condenser was the only option. The weight of the condenser was an issue.

A locomotive with no condenser is an open system. Add the condenser, and now it is a closed system.
Cheers Dan

[55fairlane]

I worked at the steel foundry in lima and remember watching as the lima locomotive works was torn down, ......sad.....

There is a shay in the park at Harod Ohio.  Just west of Lima off 309

The nickel plate rail road 765 is just a couple miles from me, I see it on the rails behind the shop on a regular basis

[uuu]

London Underground used to run a couple of condensing engines: 

https://www.ianvisits.co.uk/articles/the-surprising-story-of-steam-trains-in-the-central-line-tunnels-67050/

Wilf