1960s Boxcar Rebuilding, Part 1: The Evolution of Union Pacific's Boxcar Grain Fleet

While the 1950s brought the transition from steam to diesel locomotives, during the 1960s the nation's railroads finally moved away from the archaic 40-foot general service boxcar, to larger, commodity specific freight cars. The modernized car fleet was the product of not only new freight car purchases, but also of significant rebuilding programs to extend the lives of existing cars. Between 1963 and 1972, the Union Pacific Railroad extensively rebuilt older freight cars to meet shipper's demands for modern, specialized equipment. As the program grew, the rebuilt cars became larger and more sophisticated, and the rebuild program is best discussed in parts. During the first phase of the program, ranging from 1963 to 1967, older cars were given relatively simple upgrades, including reenforced sidesills, larger plug or combination door types, and roller bearings were inserted into the original truck sideframes. The second phase, 1968-72, was much more ambitious and resulted in "new" cars that bore little resemblance to the original. In addition to door and sidesill changes, the rebuilt cars were stretched to 50 or 60 feet in length, many had cushion draft gear or underframes installed, along with entirely new roller bearing trucks. This article covers the first phase of UP's freight car rebuilding program.

During the 1960s, Union Pacific's "grain box" fleet comprised every AAR-style boxcar design purchased by the UP, beginning with the B-50-19s, constructed in 1936, up to the B-50-47s, their final order of standard 40-foot boxcars, with 6-foot sliding doors, delivered in 1957. In addition to cars purchased new, during the early sixties, a few hundred B-50-17 and B-50-36/-37s (World War II era rebuilds) as well as the experimental B-50-22/-23 series, remained on the roster. As unique car types they were insignificant by the late sixties. However, by the mid-1960s, freight car types became larger and more specialized, and the demand for 40-foot cars in general freight service was greatly reduced. As the following tables illustrate, UP's fleet of standard six foot door boxcars declined by 44% between 1964 and 1968. At a glance, it appears that UP was intent on eliminating the 40-foot boxcar, but it is important to note that the attrition was not simply due to retirement, but to the extensive boxcar rebuilding program throughout the decade.

The rebuilding resulted in improved car design, and a reduction in the once standard 6-foot sliding door boxcars, but in reality the overall size of UP's 40-foot boxcar fleet remained steady. The first series to be rebuilt was the virtually identical B-50-38/-39s, which became the B-50-53/-54 class in 1964-65. Compared to later series, this was a relatively simple upgrade, as the cars received additional underframe support, reinforced side sills, and the trucks were converted to roller bearings. Significantly, the -53/-54s retained their original 6-foot sliding doors. Even though they were upgraded and reclassified, the 1,400 cars in the -53/-54 series remained a basic grain box. Click on the B-50-53/-54 tab for more information on these cars.

B-50-54 108875 illustrates the simple upgrading from the original
B-50-39 class. Hooper, Nebraska, August 2010.

A unique series of rebuilds was the 500 combination plug and sliding door BC-50-10s, rebuilt in 1963 from Pullman Standard, B-50-40s. Union Pacific's Albina shops installed an 8-foot plug door into the car side, next to the standard 6-foot sliding door, and a deep reenforced side sill. The enlarged 14-foot door opening allowed forklift loading of various commodities, including lumber, while retaining the car's suitability for grain loading with the conventional 6-foot sliding door. Although UP constructed other 40-foot combo door cars, the BC-50-10s were the only rebuilds of their kind, and represent a transition from a conventional sliding door boxcar, to the more practical, and much more numerous rebuilds with two flush-fitting doors.

The rebuilding of the remaining B-50-39s, and the majority of the B-50-41s, was much more extensive. Beginning in 1965, 1,100 -39s were extensively rebuilt; notably, one 8-foot, and one 6-foot plug door replaced the original sliding door. The side sills were also reenforced, and the trucks were converted to roller bearing. The original ends and roof were retained. Nearly 3,100 -41s were similarly rebuilt, sharing identical sides with the BF-50-1s, but with a different side sill profile. They also retained their original ends and roof. Because the plug doors sealed tightly, the BF-50 rebuilds were suitable for grain loading, and did not require the time-consuming coopering of the door opening. As a further convenience, grain doors were located near the top of the 8-foot plug door, so that grain could be loaded and inspected with relative ease.

While the numbers of standard 6-foot door cars did decline precipitously in the mid-1960s, most of the rebuilt cars remained suitable for grain loading, and the new double-plug and combo door designs of the BF-50 and BC-50 rebuilds, created a much more versatile cars that could be better utilized for general freight when not carrying the grain rush. As a result, retirement played a minor role in the reduction of the once numerous fleet of 40-foot boxcars. Most of the retired cars were older rebuilt B-50-17s and the B-50-36/-37s, as well as the 1937 AAR standard designed B-50-19/21s, and B-50-24/-27s, with low 10-foot inside height.

As the following chart clearly illustrates, by 1968, fully 40% of UP's 40-foot boxcar fleet was modernized, and would last in large numbers until the recession of the early 1980s.

Percent of Grain Boxes by Car Series, 1968

It is impossible to understate the importance of the rebuilt cars to UP's boxcar grain fleet. While the covered hopper was making inroads on grain shipments, as late as 1968 the UP owned just 3,195 jumbo covered hoppers (90 or 100-ton capacity), compared to more than 16,000 grain boxes. Although the writing was on the wall, UP required an extensive fleet of boxcars to handle the harvest throughout the 1960s. By 1971, the covered hopper to boxcar ratio had closed dramatically, and the 1971 Official Railway Equipment Register listed 4,992 covered hoppers and 10,924 boxcars. Notably, the rebuilt grainloaders comprised 40% of the boxcar total. With more than 4,300 cars in 1971, grainloader rebuilds must be considered one of the "essential" UP freight cars of the late sixties through the seventies.

Data compiled from Union Pacific Railroad Mechanical Diagrams, and the April 1964, January 1968, and July 1971, Official Railway Equipment Register.