I was reading the Wikipedia entry on Bittern, and it stated that she is now on her fourteenth boiler. I then just read that Flying Scotsman during its last rebuild had a spare boiler installed and that its old boiler was to also go to Bittern.

This struck me as odd as over here in the US, our steam locomotives didn't seem to change out boilers with nearly the frequency as in the UK. Was it UK practice to just swap entire boilers a rebuilds whereas in the US we would repair boilers in place?

This was discussed recently:

Multiple Boilers on Steam Locomotives

You hit the nail on the head Hot Metal. Most of the railroads in the steam-era UK would build extra boilers to facilitate quicker overhauls. While some of the basic dimensions would be the same, features such as domes, superheaters and fireboxes ( could differ between different boilers.

In some cases, boilers were used on multiple classes. Take the Drummond "Greyhound" 4-4-0 classes. The same basic boiler (including the few boilers that had firebox water-tubes, which where later removed due to maintenance issues) was shared between the 700-class of 0-6-0 freight engines, M7 class 0-4-4 tank engines, and the number of 4-4-0 classes (T9 "Greyhound", K10 "Small Hoppers", C8, L11 "Large Hoppers", S11, and L12 classes) that he designed. Of course, smaller details like smokebox sizes, cylinders, running gear parts and driving wheels would mean each class required some dedicated parts.

But back to the point. The use of extra boilers left a pool that could be overhauled as time allowed, and as such they would be ready for other locomotives that came in for heavy overhaul. The boilers that were pulled off at overhaul were then added to the overhaul pool. It wouldn't be unheard of if the same boiler was used on a single locomotive on more than one occasion, as I'm sure is the case with Bittern.

OK I missed that thread when it originally ran. Thanks

Another factor is that boilers on UK locos were intended from the design stage to be easily and quickly exchanged. That was certainly not the case with the typical US design, where, for example, the boiler shell was attached to the cylinder saddle with rivets. If a UK line had 100 identical locos, they might have 105 or 110 boilers for that design. Kept down time to a minimum and kept the flow of repair work more constant. Pretty smart, eh?

David.... I have never seen a single American locomotive where the smoke box was connected to the saddle with rivets.

Keith

Every steam locomotive I've ever seen had the smokebox attached to the cylinder saddle with body bolts. I've never seen one riveted and that would be an extremely bad idea.

OK, bolts were more common. But I'm sure I've seen that connection riveted on some steam loco. Might it have been more common on industrial locos?

In any event, I think it's fair to say that US loco designers did not make boiler change-outs nearly as easy as did UK designers. Look at any of the UK heritage railways' websites and at almost any time some or another group is pulling the boiler off a loco to be sent out for rework. The use of common boiler designs made swaps even easier. I have great respect for the various Locomotive Engineers in the UK. They were the great innovators of their age.

David new boilers were routinely applied to American locomotives. In fact all sorts of changes were made including rebuilding Reading 2-8-0's into the T class 4-8-4's. Even the smallest industrial locomotives had their boilers attached by fitted bolts at the smoke box and expansion brackets at the furnace end of the boiler. If you want an example of American railway museum's work regarding boilers I refer you to the Wiscasset, Waterville and Farmington museum here in Maine. They are restoring an 1891 Portland Co. Forney locomotive. It has a brand spanking new boiler built by the Boothbay Railway Shops.
Keith








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