What if Santa Fe had steam locomotives built before 1930 to be equipped with Belpaire fireboxes like,say 3751-class 4-8-4s or Hudsons.
I doubt it would have made any difference one way or another, performance-wise. Some railroads liked the Belpaire firebox, the PRR being the most famous example, I think because maintanance was theoretically easier, most didn’t bother with it.
They would have been ugly and nobody would want to preserve any of them.
Reading between the lines in Stagner’s (Jr) book on ATSF power in that general era, the designers were already well over permissible weight just in attempting to accommodate higher pressure in designs (with heavier boilerplate); a Belpaire firebox, especially one with circulators/syphons, is going to represent thousands of pounds of additional weight, which would require compromise in other areas of the design.
I also suspect the internal volume may be relatively less suited to high-mass-flow oil firing especially with respect to the necessary tradeoff of hot spots vs. early quench.
(((LMAO!)))
ATSF’s 4-8-4s were arguably one of the best looking Northern Type amongst all size of Northern type, including those smaller, shorter (in height and length) 4-8-4s in the States. If equipment of a Belpaire firebox provide no benefit in terms of overall performance, why bother? [:)]
Overmod brings up some good points particularly with oil firing. As to the PRR usage of the Belpaire design it enabled them to increase the square footage of the firebox without extending the overall length of the locomotive. For example the N2 when converted to the Belpaire from the USRA design increased the firebox by 252 sq ft., avoiding additional length to an already cumbersom locomotive (99" boiler) that was restricted to Lines West. This was strongly considered back then due to the tight curvature of the mainline, particularly on the Middle and Pittsburgh divisions.
As to maintenance, the boiler plates were parallel to one another avoiding curvature found in normal firebox’s. Maintenance was easier but overshadowed by the increased number staybolts required and the expense was another consideration. As stated in other posts, if it was not necessary why bother.
Locomotives that would have Belpaires includes the early Northerns,Santa Fes,Mountains,Pacifics,etc.