I understand that the Belpaire firebox was a more efficient design with improved heat transfer than conventional designs. However, I believe only the Pennsylvania and the Great Northern (I believe) really used them. Why didn’t more railroads adopt the design? Was it more difficult to design or more expensive? - Nevin
Yes, what I’ve read is that the Belpaire was more efficient but was also more expensive to build. It was virtually a trademark for the Pennsy, frequently used by the Great Northern, but not in sigificant numbers on other North American railroads. This firebox was often seen in Great Britain.
Mark
Superheated steam and feedwater heaters are arguably two technologies that most increased the efficiency of railroad steam locomotives in the early twentieth century. These developments were the death of compound-steam locomotives.
Mark
Here are some links that mihgt answer some questions.
http://www.google.com/search?hl=en&sa=X&oi=spell&resnum=1&ct=result&cd=1&q=belpaire+firebox&spell=1
Rich
In addition to having somewhat (but not significantly) larger firebox surfaces for heat transfer, the Belpaire firebox was reputed to place less stress on the staybolts, most of which were a right-angle connection between two flat plates rather than connecting two curved plates (with different radii and centers) at some non-perpendicular angle.
Belpaire fireboxes were common in the UK, and in other places where UK influence was strong. In Japan, where the models followed were mainly German and American, there was no significant use of Belpaire fireboxes.
One of the last developments in steam locomotive technology was Lima’s “Double-Belpaire” firebox. which carried the rectangular section through the combustion chamber. IIRC, there was one test boiler built, in 1:6 scale. Then Lima merged with Hamilton and the emphasis shifted to diesels.
Chuck (Modeling Central Japan in September, 1964 - with radially-stayed fireboxes)
The PRR really used the Belpaire fireboxes on all of the home made designs. The following quote about the greater surface area is a great advantage, but the work that was being done on the 1361 at Steamtown proved to be extremely difficult because of the shape.
So much for the advantage today.
CZ
It has a greater surface area at the top of the firebox, improving heat transfer and steam production. Its rectangular shape makes attaching the firebox to the boiler more difficult, but this is offset by simpler interior bracing of the firebox.
Baldwin built some 2-6-6-4 articulateds for the Pittsburgh and West Virginia with Belpaire fireboxes, and I’ve seen a photo of an early Northern Pacific 2-6-6-2 Mallet with one, similar to the early GN mallets of the same early 1900’s period. But even Great Northern opted for standard fireboxes on their Baldwin built S-2 Northerns and P-series Mountains, and some USRA 2-10-2’s for the Pennsy were delivered from Baldwin without them. So even though both US railroads were noted for Belpaire fireboxes, it wasn’t universal with all of their steam locos.
Actually, I think that the Belpaire gives a rather distinctive look to a steam locomotive, besides being quite efficient.
Tom [:)]
They didn’t use them on the O-2 or O-3 Mikes either. I am guessing none of these were by choice. The P-1s were war babies. Wood even says of the S-2 (which has almost twice the amount of weight on the drivers over an S-1), " … the capabilities of the S-1 were never exceeded by the later and more numerous S-2 class." I would bet dimes to donuts that if it had not been for the diesel the S-3 class would have had Belpaire fireboxes.
It wouldn’t be USRA if it had one.
Yes this is just pointing out the exceptions. There are always exceptions. The Pennsy & GN archetype steam locomotives have the square hump.
Even though the N2’s were deilvered with radial stay fireboxes, after the end of the USRA the Pennsy retrofitted the N2’s with Belpaire Fireboxes. But they did not change the 5 USRA Mikes used on the GR&I. They also had a few experimentals with radial stay fireboxes such as the K29.
Rick
I guess the other question is why the Pennsylvania RR was so in love with the Belpaire fireboxes? Was it just the opinions of the their senior engineers (the desire to be different), or that they built many of their own engines and thus had expertise building them or was there something about that railroad that makes those fireboxes particularly efficient? - Nevin
I would assume it was ease of maintenance, when you have 10,000 engines to take care of only having to stock one size of staybolt versus all the different sizes you would need with a radial stayed firebox makes sense. Remember the Pennsy was the “Standard Railroad of the World”, not that their standards met anybody else’s but that everything was standard on their railroad.
Rick
to begin at the beginning, the Belpaire firebox was developed in Belgium about 1860 by Alfred Belpaire an engineer seeking to simplify locomotive construction. The firebox technology of the time did not utilise radial staybolts. The crown sheet (roof or top of the firebox) was supported by a series of transverse arches called crown bars. The crown bars sat on the knuckle (curved portions along the sides of the crown sheet where the crown attached to the side sheets) of the firebox. The staybolts threaded into the crown bar and went through the crown sheet at 90*. The outer shell of the boiler was supported by bolts which radiated from the curved top of the crown bar and also passed through the shell at 90*.
Belpaire reasoned that he could do away with all those radial staybolts by making the crown bars a bit taller and then bending and riveting the shell directly to the crown bars. (this gave the outer shell the unique square shoulders look.) As late as the 1930s some small locomotive boilers in the UK (Hudswell and Hunslett if no one else) were built this way. I know, I’ve worked inside some that were built like this, the construction came as a complete shock to me.
By the early 1900s crown bars fell from favor, so when larger locomotives were built the flat sides allowed staybolts to be run from side to side and up and down maintaining the optimal 90* to the sheets without the crown bars
The technology of the era was flange and rivet. attachment of the Belpaire firebox was no more difficult than the construction of the eccentric course of a wagon top boiler. The Belpaire’s shape gave the needed dry steam space without resort to the eccentric course.
the disadvantage of the Belpaire firebox lay in its rows of cumbersome crown bars which made washing the scale off the crown sheet an incredi
Actually, a lot of older locomotives (say late 1800s) were equipped with belpaire fireboxes.
One item about the GN’s O2 and O3 class Mikes, the O2 was a single locomotive class acquired in a merger. The O3s were USRA lokeys, the only puppys the GN would purchase. If I am not mistaken, the S1 class Northerns outlasted the S2s due to their better pulling ability which was probably the result of the smaller, 72" drivers vs the S2 series 80" drivers, but I certainly am no steam expert by a loooooong shot…[C):-)]
Hi, Tom -
It was the GN P-2 series Mountains, along with the S-2 Northerns. The O-3 Mikes were also exceptions, as were a few smaller engines acquired from other roads, such as the F-12 Consolidations (only 2 on the roster, I believe). Otherwise, use of the Belpaire was pretty much standard GN practice to the end of steam.
While the CNR didn’t make a big splash in the Belpaire pool, they did have 75 of these, in three classes:
Built in 1923-24, most of them lasted right to the end of steam.
Wayne
Quite a few locomotives were built with Belpaire boilers for railroads large and small by Brooks and other Alco plants around the turn of the 20th century. These even included some narrow gauge engines.
Tom
“Today’s steam question”—
asked 8 years ago.
Time flies.
Ed
I noticed that too. But it’s a question that some newer folks may have, and it’s not bad to resurrect such things now and then. However, you do make a good point. Sometimes people ask very specific questions about a situation that is important to them at a specific time. A response eight years later isn’t much use in those cases.
Tom
In the “you can’t win” department, either people resurrect old threads and run the risk of being made fun of, or they start new ones and are chastised because “there is already a thread” on that topic.
For myself, if someone has a contribution to make to an old thread I think adding to it is the way to go. I’d rather see one thread be a really complete discussion on a topic (even if the OP long since has become “anonymous”) than have to chase down dozens of threads.
Dave Nelson