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P.S. Waverley

Posted: Sat May 11, 2019 1:41 pm
by Mike Rometer
A visit to the P.S. Waverley web page shows that her boilers are now extinct. They are quite obviously looking for donations. There is plenty of 'gum bumping' about the problem on other sites.


https://www.waverleyexcursions.co.uk/

Re: P.S. Waverley

Posted: Mon May 13, 2019 3:53 am
by Bert Blik
It Seems to me that the lifespan of these modern boilers is getting less . Her original double ended scotch boiler lasted 34 years wheras the last 2 sets only lasted 19 years each.
I do hope they find the funds to replace these as nothing in the world compares to that big Rankin & Blackmore triple expansion going flat out and the world would be a poorer place if we could only see these as a static exibit .

Re: P.S. Waverley

Posted: Tue Nov 19, 2019 9:56 am
by Mike Rometer
This link was sent to me by someone of similar interests.


https://www.paddlesteamers.org/news/nat ... EjF7_2pm1U

Re: P.S. Waverley

Posted: Tue Nov 19, 2019 10:43 pm
by fredrosse
"It Seems to me that the lifespan of these modern boilers is getting less . Her original double ended scotch boiler lasted 34 years wheras the last 2 sets only lasted 19 years each. "

I wonder how this could happen, considering the wealth of knowledge available to boiler design engineers, and boiler operators. With proper treatment such a boiler can easily last for 60 years. I was firing the boilers on Concordia (Italy, Lake Como Sidewheeler) in 1986, the boiler was original, built in 1926. Re-tubing a Scotch boiler is not that expensive, and I would hope that the shell and sheets were thick enough to easily last for 60 years. When building a new boiler, adding a generous thickness margin to the plates costs a pittance, and assures that only re-tubing might be needed for 60 - 100 years. The tubes have much thinner walls, and therefore may require replacement, but should last at least 20 years with reasonable operating procedures.

I can imagine that when the Waverly boiler was replaced 19 years ago, the management went for the lowest price, with the minimum plate/sheet thickness according to design rules. That is a reason to have a knowledgable "Owner's Engineer", to watch over what the bidders are offering, and assure the owner is not purchasing inappropriate components.

Re: P.S. Waverley

Posted: Thu Nov 21, 2019 5:48 pm
by cyberbadger
I agree with Fred's assessment - boiler manufacturers have all the information to do it correctly.

Whether or not it is in their financial interest to make a boiler that lasts 60years - the answer I'd expect from most modern boiler manufacturers is no. They may not get the chance for repeat business this way - so you have to make it worth their while. I do not like this at all, but I can understand it.

I think the important fact is that within a year there was enough monetary support from voluntary sources is an excellent sign that people really do care. ;)

Or you could just summarize it as, they don't make em like they used to.

-CB

Re: P.S. Waverley

Posted: Sat Nov 23, 2019 8:11 pm
by Kelly Anderson
fredrosse wrote:
Tue Nov 19, 2019 10:43 pm
"It Seems to me that the lifespan of these modern boilers is getting less . Her original double ended scotch boiler lasted 34 years wheras the last 2 sets only lasted 19 years each. "

I wonder how this could happen.
There was a thread on the Railway Preservation Interchange several years back that covered this subject. The thrust is that modern steel is liable to corrode at a greatly accelerated rate compared to the steel that antique boilers were made of. In addition to the discussion about tubes below, I have seen lower firebox sheets that I helped to install have to be replaced due to corrosion, when the sheet just above, made of antique steel was as smooth as a baby's butt. Note that a local industrial boiler factory considers twelve years as the life span of the boilers that they build. Here are some of the pertinent quotes:
Kelly Anderson wrote:
Bobk wrote:So does everyone buy or accept boiler tubes without a material certification? If you have tubes laying around what were the circumstances for purchasing or did they just show up on the property. Generally you specify everything on your purchase order even stating that material cerifications and Ht Numbers to be furnished. If you have tubes laying around and they haven't rusted beyond recognition then perhaps you can find the heat number still on the tubes. This HT number is your traceability to certifications held at the manufacturer of the product.
The following are the random recollections of a non-metallurgist sitting slack jawed in the ESC peanut gallery:

It seems that certified tube material (SA-178 A is probably the most commonly used standard) doesn’t do much to protect you these days. At the recent Engineering Standards Committee meeting, a large portion of the first day was spent in a metallurgy clinic of questions and answers to two retired metallurgists who spent their careers in the local steel industry, and it seems like we have a number of details working against us these days.

1. The accepted standard tube material (SA-178 A) has had the percentage ranges of alloying elements in the official recipe considerably widened over the years to the point that any given heat of SA-178 A tubes can be quite corrosion resistant, or can be “rusting out on the show room floor” garbage, and still meet the SA-178 A spec. This leads to a “luck of the draw” situation where our #90 is closing in on 1,300 service days with tubes that still look new, while our steam Thomas just had her tubes replaced after 300 service days due to having lost over ½ of their thickness. The metallurgists noted that you can tighten the specs of the alloying elements of your particular tube order to stay in the more corrosion resistant range, but that you will need to order a mill run of tubes to get your custom mix. Ka-ching.

2. Single orders of tubes under one set of mill test reports may or may not be from the same heat, regardless of what the paperwork may say. As long as they are all SA-178 A tubes, left overs from different heats can be consolidated by the steel company under one MTR to dispose of them. Not too ethical, but they said it is done. This can explain having one tube in a boiler looking pristine, while the tube next to it is shot, even though both are under the same MTR and were installed at the same time.

3. As the steel industry has modernized, the newer techniques (electric furnaces and the like) have resulted in a much cleaner product than what was available in the “steam era”. Ironically, the dirtier the steel, the more corrosion resistant it is. I asked one of the metallurgists where we could go to get some good old dirty open hearth or Bessemer steel, and he thought Russia or China, but advised me “not to go there”.
Kelly Anderson wrote:
Bobharbison wrote:Interesting to read about how the standards are fairly loose.

So, now I'm curious about the "lesser grade" tubes that still meet spec. Obviously they're being placed in a boiler somewhere. What kind of boilers are they used in, and why are they acceptable there?

Yes, I understand that a stationary boiler has less stress on it, but does that make the tubes last that much longer? Kelly mentions tube losing their thickness, what causes that? Is it from the water, the flue gases or both? How do other applications not have the same problem you would have on a steam locomotive? Or, if they do have the same problem, then why have the standards been lowered?
I understand that modern commercial boilers are designed around a life span of 12 to 15 years, after which they are thrown away and replaced, no questions asked. From a material longevity standpoint, that means it sucks to be us since we preservationists would like to think that our replacement boilers are just getting broken in in that amount of time. It will be interesting to see how many new boilers that have replaced 100 year old originals will then need to be replaced themselves after only a few years.

The second issue is that steam locomotives usually operate under the worst possible feed water conditions, intermittent duty, 100% makeup, often from multiple sources, and thoroughly aerated as it is poured into the tender and sloshed around. Water treatment helps of course, but comes with its own set of side effects.
Linn W. Moedinger wrote:You really only have two choices if you want to ensure absolute consistency, get a mill run to your specs and have your lab test it upon arrival before paying - we do this with staybolt material - or you can test each piece. The problem with the second option is what to do with the pieces you don't like other than put them where you can keep an eye on them.

All this makes lay-up procedures and water treatment all the more important.
J.David wrote:I too was at the aforementioned ESC meeting. One of the things I came away with was that the dirty, impure steel seems to hold up the best under our operating conditions. In the old days, the mills "killed" the steel with silicon (dirty). Later on they went to "killing" the steel with aluminium (clean). Early on steel was mostly made from pig iron (clean), now a lot of it is made from scrap (dirty, with a lot of trace elements).
From the chemical test reports which accompanied the tubes that Linn brought in for "show & tell", it was obvious that the tubes which had suffered some of the worst pitting I have ever seen were "clean" steel, while the ones which showed just typical scale, with an occational little pit or two were made from "dirty" steel (probably "auto frag" (automobile fragments) with some chromium, nickle and copper in it.
For years, it has been accepted knowledge that "modern steel" made from scrap wasn't as good as "the old stuff". What an eye opener that session was!