Bellepair firebox

[woodsie]

Hi everybody,
What is the reason[s] for the Bellepair firebox that the Pennsy adopted, but so few other RRs used?
Thanks,

[Pennsyjohn]

The Belpaire firebox was adopted by the PRR to maximize the flame area.
It allowed a larger grate area, therefore a larger area for heat transfer.
It also burned bituminous coal more efficently.
In case you're interested, I think the GN tried a couple.

I hope that this answered your question

John

[ex Budd man]

The Great Northern did use the Belpaire style fire box as did PRR. The advantage was equal length stay bolts on the sides and top of the boiler. This allowed for equal expansion and contraction of the fire box which lessened leakage into the fire box and (some say) made it stronger. Dozens of papers have been written about the pros and cons of radial stays vs. equal length stays by more learned folks than me, but that is what I got from reading a few of them.
The Brits and French were split on them depending on egos in the design department. The same can be said for the rest of Europe, some designers liked them, others didn't.

[2nd trick op]

The Burlington also rostered a fair amount of power with Belpaire fireboxes in the early years of the Twentieth Century, particularly on some of its Mogul (2-6-0) and Atlantic (4-4-2) classes, but this was before it was brought more directly under GN control, if memory serves me correctly.

I think it's also worth recognizing that the J-1 Texas (2-10-4) locomotives, the only really successful class of later PRR steam power, did not feature a Belpaire, but this was due to the War Production Board-mandated copying of a 1929 Lima design built for the C&O. As with the NKP's Berkshires (2-8-4), and all of N&W's later power, the decision to standardize on a limitied number of designs paid substantial dividends.

[Allen Hazen]

2nd trick op--
"the J-1 Texas (2-10-4) locomotives, the only really successful class of later PRR steam power, did not feature a Belpaire" Yes-- and the one complaint about the J-1 that I recall seeing was that they had staybolt problems! This is weak evidence (after all, the problems could have been caused by lots of different factors), but a BIT of evidence, that ONE advantage of the Belpaire firebox design was lower-maintenance staybolts.

Whatever the advantages/disadvantages were, they don't seem to have impressed the railroad world as overwhelming: different railroads around the world preferred Belpaire or roundtop fireboxes apparently at random. Some pre-nationalization railways in Great Britain preferred Belpaire (notably the Great Western), others roundtop (notably the London and Northeastern Railway). Belpaire was adopted as standard on the steam designs for new construction by British Railways after nationalization.

Weird sidelight: the Victorian Railways (Australia) R-class, some of which are still serviceable for excursions and were used on "plandampf" Melbourne-Warnambool trains until a few years ago, are 4-6-4 but have Belpaire boilers: to an American eye, there is something disorientingly weird about seeing a Hudson with a Belpaire boiler!

[erie2521]

I believe the Pittsburgh and West Virginia had some engines with Bellepair fireboxes. I seem to recall a photo of a 2-6-6-4 with one. Ted

[2nd trick op]

Mr Hazen wrote:

2nd trick op--
"the J-1 Texas (2-10-4) locomotives, the only really successful class of later PRR steam power, did not feature a Belpaire" Yes-- and the one complaint about the J-1 that I recall seeing was that they had staybolt problems! This is weak evidence (after all, the problems could have been caused by lots of different factors), but a BIT of evidence, that ONE advantage of the Belpaire firebox design was lower-maintenance staybolts.

An astute observation, which leads me to speculate on another possibility: Might the Pennsy shop forces long-time orientation toward Belpaire boliers have contributed to this issue once the J-1 class(es) started undergiong regular maintenance? In a Keystone (PRR Technical/Historical publication) from about ten years ago, I can recall an article by a shop worker hired after the PRR decided on one last round of steam overhauls around 1950.