SAL B-3, B-4 and B-5 Composite Box Cars


SAL B-5 16709, Charles Winters Photo, circa 1950

Seaboard Air Line’s most significant boxcars from the pre-WWII era were the composite B-3, B-4 and B-5 class cars delivered in several series between 1926 and 1931. Seaboard took delivery of 1000 B-3 class cars in 1926 (numbered 12000-12999), supplementing the road’s large fleet of ventilated box cars and replacing several obsolete 30-and 40-ton double-sheathed box cars outright. Rated at 40 tons, these single-sheathed cars featured Pratt trusses, six-foot Camel doors, Andrews trucks, 7-8 corrugated ends and fishbelly centersill underframes. Inside height was 8’ 7” and inside length was 40’ 6”. According to Richard Hendrickson, Seaboard’s B-3 cars were variants of the 40 ton 4C-XM1 ARA standard design.

In 1929, SAL ordered 1000 B-4 class cars from both Pullman and Standard Steel. Numbered 13001-13999, the B-4s were virtually identical to the B-3s. The B-4s maintained the same 40-ton rating and interior dimensions as the B-3s, as well as the fishbelly centersill underframe and Camel doors. However, there were several notable differences, including Pullman flat plate ends (often called “X-29” ends), AAR trucks, and a small 18” lumber door on the B end. Like the B-3s, the B-4s were also variants of the ARA 4C-XM1 design.

Seaboard received its last composite box cars—the B-5 class—in 1930. Unlike the B-3s and B-4s, the B-5s followed ARA’s 50-ton 4D-XM1 design and featured Pullman flat ends, 50-ton Dalman trucks and Youngstown corrugated steel doors. Pullman built the first 1000 B-5s (numbered 15000-15999) and Richmond Car Works built an additional 1000 cars (numbered 16000-16999). These famous cars were seen around the country, and were SAL’s signature box cars throughout the Depression, WW II, and into the early 1950s.

The B-3s took a beating during the WWII years and many were retired or converted for Maintenance of Way service by the early 1950s. Photographic evidence also suggests that Seaboard rebuilt several B-3s with steel sheathing underneath the Pratt trusses (similar to GA RR’s rebuilt USRA SS box cars) prior to WWII.

Most of the remaining B-4s and B-5s were modified in an ambitious rebuilding program beginning in late 1950. SAL re-equipped the cars with steel sheathing, rebuilt interiors and new brake gear, but the cars retained their Pullman ends, six-foot corrugated steel doors and fishbelly centersill underframes. Initial cars received heavy steel plate welded over the top of the existing Pratt trusses from the top side sill to the lower side sill. Later cars received steel plate welded over the top of the existing Pratt trusses from the top side sill to nine inches above the lower side sill, leaving the lower nine inches of the trusses exposed. These cars were equipped with eight foot corrugated doors. When completed, all rebuilt B-4s and B-5s resembled the B-6 class cars (ARA 1932 cars) in appearance and design, although they retained the B-5 class designation. Interestingly, almost every rebuilt B-5 kept it’s original Dalman trucks. Many of these cars lasted on the CSX into the early 1990s in Maintenance of Way service.


SCL 772761 (rebuilt B-5) in CSX MX Service, Hamlet, NC 1991, John Golden Photo

Contributed by John Golden. Thanks to Richard Hendrickson and Paul Bizier

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