I've been doing some reading on LNER Class A-4 locomotives in preparation for an upcoming trip to England. In reading wikipedia articles that each of the existing A-4s have had 11-14 boilers during their active service carers. I found this surprising. I'm guessing that every couple of years the boiler was simply swapped out and a fresh supply of new and rebuilt boilers were kept in rotation. Was this the case and how common was this practice?

We "Brits" (well, this guy well-versed in UK rail practices) really wonder what the heck is wrong with you chaps that you DON'T do it.

To be fair, the practice is common enough if the loco is designed with it in mind. U.K. boilers are fairly smaller and more "streamlined" in attachment than most North American boilers. You don't need to keep that many spare boilers around-- two or so from each major express loco design should do it. In some of the later days, better boilers were even "cascaded" down from otherwise failing locos to other loco frames to extend loco life.

The philosophy was perpetuated long enough that some of the BR diesel models, most notably the Class 47, 50, and 55 diesels, were built with easily-swapped engine designs. In the case of the Class 55 "Deltics," the "power units" were integral engine/generator units that could be easily swapped out with a special lifting beam. When the Deltic Preservation Society acquired its first two Deltics in 1982, it was careful enough to go on a major parts buying binge, acquiring no fewer than seven spare power units as well as the p/u lifting beam and other assorted specialised tools and equipment.

I think it's fairly well known that LNER 4472 Flying Scotsman was on its second or third boiler when retired in 1963 (fifty years ago last month), and Alan Pegler had the foresight to acquire a spare boiler along with the loco when he bought it. There also is/was at least one spare A4 boiler floating around the private owners of A4 Pacifics.

See also:
viewtopic.php?f=1&t=4262

https://groups.google.com/forum/?fromgr ... YONOYhha5A

https://groups.google.com/forum/?fromgr ... Q2qfrFBc-Q

It was common in Poland, also, to swap boilers as part of a rebuild. Many/most extant Polish locomotives have a sisters boiler.

The practice of swapping boilers wasn't unknown here in the USA either. For example, Rio Grade #464, (at the Huckleberry RR) during one of her major shoppings on the D&RGW, acquired the boiler of #454.

The boiler which was on Scotsman was an A4 boiler. It now has the A3 boiler. The A4 boiler will probably go on Bitten at its pending over haul.

Certainly it was common to have several spares in the rotation in the Uk. This also applied to many components and on one GWR loco as many as 20 other locos numbers where found.

Yes, it does make good sense to have interchangeable spare boilers. I find it fascinating that a locomotive would have 14 boilers in a roughly 30 year service life.

So it would be more correct to say a locomotive may have had 14 DIFFERENT boilers, rather than 14 NEW boilers over its service life.

On the Pennsylvania, there was one K4s that had its boiler swapped with an L1s in the '20s.

Though, I am not as much of an anglophile as Mr. Mitchell, I do know on the Great Western it gets even crazier. The GWR had several "standard" boilers that were used on different classes and wheel arrangements. Thus, a boiler could end up, not on on a different locomotive, but a different class of locomotive.

Swapping boilers during major overhauls was commmon in Germany.

In the USA, the Delaware & Hudson, which ran heavy 2-8-0s as mainline coal drag power when most everyone else was buying 2-8-2s and 2-10-2s, did a lot of boiler swapping at major overhauls.

The Pennsylvania had a huge number of "identical" boilers: 425 K4S 4-6-2, 574 L1S 2-8-2... did they swap out boilers regularly within each class, or not?

- Doug Debs

You're dreaming if you think there was ONLY one. The boiler design was absolutely identical.

From the Wikipedia page:



That's 14 boilers is just under 30 years of service. Pretty amazing in my opinion. I don't think there is any comparison here in the states.

I'm not dreaming. I only know of one swap between classes K4s and L1s because it was noted on a list, and a photograph of the hybrid K was published. There may have been more such exchanges, but I wouldn't claim it for a certainty without proof. The Pennsy did other boiler swaps within classes as noted on rosters, but such notes are few. They may have prefered to keep "body and soul" together for whatever reasons they had. You all know the PRR did things in its own way.

The Grand Trunk Railroad swapped a few boilers around with some of its Pacifics, and later the CNR did the same with some of its Mikados. They even conjured up a few new engines using spare boilers and I recall seeing one photo of the "new" Mike sitting next to the "old" Mike that donated its boiler, (having since received a new boiler), parked in a deadline somewhere.

Some years ago, while working on the boiler of an unnamed locomotive in Scranton, we came across the following stamped into the front flue sheet of that boiler: "X-L-1-s." Now since that particular locomotive was not an L-1s but a member of a class of locomotives said to have a boiler identical to that of an L-1s, one must presume that it was indeed the fact. Years earlier, an old-head boiler maker who had retired from the company's main shops in Altoona asserted that it was common practice to replace the boilers on that particular class of locomotives every 8-10 years because they were used so hard. I wasn't about to argue with the man because he had been there and done that. But what do I know?

One of the selling points of diesels was the way the power unit (engine-generator assembly) and trucks could be changed fairly quickly. Changing out a steam boiler, especially one that has been in place for a while (and has a lot of nuts and bolts that have to be cut off and replaced) would seem to be a more challenging job.

The subject line made me think of Fairlie locomotives, that had two boilers at the same time.