Thursday, December 19, 2019

Project #1 - ATSF Bx-11, 12, and 13 classes...and RI

It should be obvious by now where we are starting with this project. As we noted in some earlier posts, in 1950 box cars using single sheathed construction were still an important part of the national fleet.

In 1924, a standard design for single sheathed box cars was approved by the ARA, and in 1925 the two designs were designated 4C-XM-1 (40-ton) and 4D-XM-1 (50-ton).

The design incorporated the ARA center sill (approved 1922) with a external bracing using pressed hat- (or U-) section steel in a Pratt truss configured with two diagonals on either side of the door. They are often referred to as "7-panel" cars. Cars of this standard design were built for a number of eastern and midwestern roads. These cars had an interior height and width of 8'6".

ATSF Bx-11

As the decade progressed, many roads were building cars with larger dimensions than the ARA standard, particularly western roads. In 1929, ATSF adopted the basic ARA standard design, but increased the interior width to 9'2" and the height to 9'6" for 2,000 box cars in their Bx-11 class.

The cars had "indented" Dreadnaught ends with 3 corrugations above and 4 below a center corrugation where the two halfs of the ends were riveted together. They had radial roofs with wood running boards, Youngstown steel doors, and Ajax powered handbrakes. They were equipped with KC-brake systems, and rode on ASF Dalman Two-Level trucks.

A unique spotting feature is the use of tension rods at the corners of the sides, instead of flat steel strapping that was usually used on single sheathed cars. Over the years many of these tension rods were removed, and photos often document cars with only one rod on a side, instead of two. In some cases a horizontal brace is added to the final panel about halfway up the car, in others the rod is simply removed, and no additional bracing was added.

ATSF Bx-12

In 1930, the ATSF added 3,500 Bx-12 class cars to the roster. These were virtually identical to the Bx-11 class, except for the use of Dalman One-Level trucks, which have never been offered in HO scale.

In later years, the Bx-11 and Bx-12 classes are grouped together in the ORER.

ATSF Bx-12 class builder's photo
Note the radial roof and tension rods.

ATSF Bx-13

In 1931, and additional 1,000 cars were added as the Bx-13 class, but used Murphy Solidsteel roofs, a precursor to their familiar rectangular panel roof, but without the raised rectangular panels.

ATSF Bx-13 class in 1/1/52 at Fayatteville, NC. Courtesy of Bob's Photos
Note the peaked Murphy Solidsteel roofs instead of radial roofs of earlier classes.
Note that the B-end tension rod on the is no longer present on this side.
This car has also received AB Brakes.

All three classes, accounting for 6,500 cars, were very long lived, although not without alterations. The less common Pratt truss along with the tension rods unique to these cars and the 500 Fe-U 50' automobile cars making them easy to spot in photos and on your layout.

Looking back at our previous posts, 22% of the ATSF box car fleet in 1949 were single sheathed box cars. In 1950, there were 6359 of the Bx-11, 12, and 13 classes in service, accounting for more than 21% of their entire 40' box car fleet, and nearly 97% of their single sheathed cars. This is an important class for modelers of this era, of 5 out of every 20 Santa Fe 40' box cars. Although as we'll see in the next post, that they weren't all in the original configuration.


RI 141000-142999 series tall Pratt truss single sheathed box cars

The Rock Island owned 1,000 ARA standard XM-1 box cars. In 1930 they continued using this design, but with the larger dimensions used by the Santa Fe. These 2,000 cars had 4/4 Dreadnaught ends, Hutchins Dry Lading roofs, Youngstown steel doors, power assist horizontal brake wheels and Morton brake steps, KC brakes, and ASF Dalman Two-Level trucks with Barber Lateral Motion devices.

RI 142798 builder's photo
Note the flat strap steel stiffeners in the lower corners
as opposed to the tension rods on the ATSF Bx-class cars

The RI rostered a lot of single sheathed cars, and in 1949 nearly half of their box cars were of that type of construction. Of their 40' box cars, these accounted for almost 12% of them, and they accounted for 23% of their 40' single sheathed box car fleet. Like the Santa Fe cars, they were long-lived, with only 19 fewer cars in 1956, and 316 still in revenue service in 1965.


These are the first four cars of this project:
  1. ATSF 124000-125999 Bx-11 class
  2. ATSF 126000-129499 Bx-12 class
  3. ATSF 135000-135999 Bx-13 class
  4. RI 141000-142999 series tall Pratt truss box cars
Each car will be available with either KC or AB brakes, accurate painting and lettering as appropriate for the era, and correct details for each class including roofs, strapping or tension rods applied as per prototype photos, but for those with fewer than 4 applied the remainders will be provided in the box for the modeler to apply, if desired.

As noted previously, these will be HO scale injection-molded plastic models, available ready-to-run or as kits, and parts available separately.

An old MDC model superficially resembles the Bx-13, with lots of inaccuracies, and only the Bx-11, 12, 13 class cars have been produced as excellent resin kits by Westerfield. The RI cars were produced as resin kits by Sunshine. Otherwise, no plastic, or even brass models to our knowledge, have been produced in HO scale of these important prototypes.

We should also mention that we are working with the Santa Fe Railway and Historical Society to ensure that the models are as accurate as possible. But we also know that there are lots of experts out there that love to talk about their passion. We love freight cars, but we certainly don't know everything. If you think you have information or photos that will help make these models better, then contact us. We love talking trains and freight cars. And come see us in person at Cocoa Beach and Springfield.


  1. I have a digital copy of the original Bx-12 general arrangement drawing that you are welcome to.


    1. Thanks! I just realized I hadn't added the email address to the site. It's info [at]

  2. Wow looks great, look forward to these, would definitely pick a few up!

  3. I would be up for these but would be curious to see what reweigh dates you are going to put on them, most of the transition era cars end up with reweigh dates in the 50's I model 1947 so the last thing I want to do is to have to rub off numbers and re do them. Would it be possible to let us know what reweigh dates you are thinking of doing and if they are the 50's would it be possible to leave that area blank and include a small decal sheet with the car. At this point I'm no longer able to paint and decal undecorated kits.