Friday, December 30, 2011

Modeling project: M&StL box car

At the meeting in Lisle, Illinois last October, I was intrigued by a clinic given by Clark Propst, entitled “M&StL Freight Cars You Should Build.” Though this railroad was not large, it did have a freight car fleet of some size; of greater importance, every model freight car fleet does need a few representatives of “unlikely” railroads (unlikely in the Gilbert-Nelson sense). Whenever samplings of prototype data are done, a few cars always show up from relatively small railroads.
     Although none of the car projects Clark presented directly inspired me, I did begin to think that some suitable Minneapolis & St. Louis car might be a good subject. With that thought in the back of my mind, I was browsing in Railroad Prototype Cyclopedia issue 18 awhile back, specifically the article on the ARA 1923 standard box cars. Turns out that the M&StL bought 500 of these cars, their 24000 series (even numbers only). The article includes four prototype photos.
     Mental wheels started to turn. I realized that the old Train Miniature single-sheathed box car is somewhat like the single-sheathed ARA car, though details are not up to current standards. Might I have one somewhere in my freight car stash?
     Yes, I did. Moreover, it turned out to have some of the features of the M&StL cars. (You always have to check the details of the particular model, because Train Miniature or TM mixed and matched car sides, roofs and ends, sometimes in ways that had no prototype.) Though lettered as a Wellsville, Addison & Galeton (WAG) car, it had wood ends, outside metal roof, and wood doors, all features of the M&StL cars--though the ends weren’t quite right--more on that in a moment. The sides are a Howe truss arrangement instead of the ARA Pratt truss, so the model can only be a stand-in, but would have the right general look. Here is the model out of the box:

The WAG lettering already present, though interesting, would only be correct for cars obtained by the WAG in 1958, well after the time I model, and in any case the WAG cars were plate-end cars purchased from Boston & Maine, and the execution of the TM lettering is poor.
     How about decals for M&StL? I always like to be sure I can letter a model before embarking on the construction work. I sent e-mail to Clark to ask where I might get appropriate decals, and he replied that Mark Vaughan offers a set which, though intended for steel cars, could mostly be used for the ARA cars, with different dimensional data. I promptly ordered a decal set, Mark’s set BB. If you’d like to take a look at Mark’s listing, here’s a link: .
     Meanwhile, I studied the TM kit further. The ends need to have the bracing somewhat like standard ARA bracing, instead of TM’s smooth end. Here’s a drawing of the prototype standard ARA end, an end which most buyers of these cars did not select, but apparently M&StL did:

although the M&StL end was not quite like this (more in a moment). The car body in the TM kit has this end:

Not only the incorrect placard board needs to be removed, but also the ladder, as the prototype ladder was outside the diagonal brace. The inset roof end shown in the drawing was apparently not used by M&StL, though it could be simulated with a crosswise brace. I decided to neglect the annoying fact that the ARA-design end had horizontal sheathing boards, and the TM end has vertical ones.
     For this kind of work, I like to use an Exacto No. 17 (chisel) blade, to carve off the parts to be removed. I keep the blade under control, so when it cuts through the part it doesn’t skip ahead. After carving off most material, I sand lightly to make sure the surface is level. Then the board divisions are re-scribed through the areas where material was removed. The end then looks like this:

     Next the end bracing needs to be added. I used styrene scale 4 x 4-inch strip, which is oversize for the prototype bracing but is a good match for the simulated Z-bar bracing of the TM kit. (Might as well have sides and ends look about the same.)
     The styrene strips were sanded to approximate the shape of ARA hat-section braces and cemented to the car ends. I also drilled holes for wire grab irons on the ends, and for two grabs at the left of the sides (the TM model has only one side grab, as is correct for mid-1920s freight cars, but after 1931 two were required, and the second ones were added to older cars when next shopped).
     The six-rung ladder for the ends was a minor problem, as none of the commercial ladders I had in my stock had a rung spacing matching the side ladders (normally ladder rungs on sides and ends are equally spaced and located in the same plane). The nearest ladder spacing I had was the InterMountain 1937 AAR box car ladders, which I obtained (along with many other useful parts) in their Body Details set, part no. 40700-59. I cut off the lowest rung and added styrene spacers to permit the ladder to stand off above the end braces (the prototype ladders were arranged the same way). The completed A end looked like this before painting:

Obviously roof detailing remains to be done in this photo, and I’ve omitted the flanges by which the car’s sheathing was bolted to these end braces.
     The door tracks on the TM kit are rather oversize, especially the immense ledge which acts as a lower door track. I removed most of this, as well as the large “claws” on the door, which guide the TM door along the bottom track if it is operated (mine are glued on). The TM doors are intended to represent a bottom-supported door, whereas the M&StL cars had top-hung doors, but I decided not to correct this detail.
     The TM running board is seriously over-thick, but can be used if it is filed and sanded down to a realistic thickness. I did that, and replaced the cast-on corner grab irons with Tichy wire parts. I also glued the TM kit weights to the inside of the floor, using canopy cement (R/C-56) and adding about one inch of steel strip at the door location to add a little weight. I cut off the coupler pocket box lids so they would be separate parts, and removable if necessary for coupler maintenance.
     Of value beyond this one car project is a trick I often use for addition of metal sill steps. Drilling into the car body itself can be problematic if the shell is thin. So I glue a short length of scale 4 x 4-inch styrene inside the side sill, thus thickening the area where drilling is to be done. Once the cement is well set, I usually drill approximately along the interface between the car shell and the styrene block. Here’s a photo to show how it looks when A-Line Style C steps are attached:

     Finally, after painting, applying the Vaughan decals, and weathering the model, here is the final result. I used Tahoe Model Works Buckeye trucks.

     At this point a prototype photo may be useful. This one is from the Bob’s Photo collection, and location, date and photographer are unknown.

     This project was chosen as another example to show the kind of upgrades and modifications one can perform to get closer to a particular prototype, without any particular goal of creating an “excellent” model. And remember, this model is a stand-in. For me, this will be what I call a “main line” model, normally only used in passing trains, so correcting every detail just isn’t essential. But now I’m glad to have an M&StL freight car in my fleet.
Tony Thompson


  1. Tony, I note the proto picture have braces at reverse to the model. I check my few outside braced N scale and your Vol.4... for example B-50-15 have braces like thr M&StL car, but for example a B-50-13 (8 panels) is braced as your model.
    Curious if is a rule or a reason (stength?) for the variant.
    Keep the good work!

  2. Yes, they are the reverse. This is what I meant with my comment in the fourth paragraph about Howe vs. Pratt truss patterns. If you look at my subsequent post entitled "M&StL box car: addendum," you will see a photo of a prototype with the same arrangement as my model.

    The Howe truss is a holdover from wood bridges (and is the name of a patent for such bridges), and is well suited to wood construction, because the diagonal braces are in compression when loaded, a good stress state for wood. The Pratt truss (also a patent) places those diagonals in tension when loaded, a stress state which steel handles very well but wood would not. So why would a steel frame on a freight car use a wood-technology design? We always assume it was the conservatism of old mechanical engineers, who had used Howe-truss designs in their youth and kept on using them. This M&StL car may be a good example, because it uses the old-fashioned Howe instead of the more modern Pratt design of the ARA standard car.
    Tony Thompson

  3. I should correct a misstatement in the last sentence of my reply (above) to Enzo. The M&StL prototype car DOES use the Pratt truss design of the ARA standard box car. The simplest correction for any reader would be to simply omit that concluding sentence. My apologies for any confusion,
    Tony Thompson

  4. Tony, thanks so much. Very clear!
    Several customers in my business have comment my explanations this way : "A really knowledge man is who is able to simplify the concepts and communicate it never using strange words...." ... And you’re!
    I've not noted your "Howe vs. Pratt truss patterns" sentence.

  5. Thanks for this article! I am using it as a guide to build my own M&STL XM1 boxcar however I am using an Ulrich ARA boxcar as the basis of the build. Ulrich boxcars, although not as numerous as the Train Miniature/Walthers boxcars, are not hard to find on eBay. They come with the correct Pratt truss arrangement. Some of the boxcars have ARA composite ends and some have corrogated ends so if you're going to buy one, make sure you know which ends you're getting. The composite ends have cast-on ladders but they are the 6 rung type. The main drawback to these models is that the side braces are way-too-thick but the composite ends are also so if you don't mind this, the car can be made into a decent model.

  6. Good suggestion, Jeff. I have one of those Ulrich models, so I can appreciate what you mean. Mine has corrugated ends, but I was not aware that Ulrich had made two different ends.
    Tony Thompson

    1. The composite ends are usually found on the Ulrich stock cars and they are cast out of Bakelite. This makes them easily drillable for adding details however they are much more brittle than the plastic ends of the TM cars.

  7. Hello Tony,
    Great info you have here and i am using it to design it in Sketchup for later use in 3Dmodellbahnstudio.
    A question; Did this model had a runningboard also over the roof and if so, what material was it made of ? Wooden planks ?

    If possible, a picture of your model on it would be nice !

    Greetings from Brazil.

  8. Yes, wood running board. Remember that this model is a stand-in, having a Howe truss body frame instead of a Pratt truss like the prototype. (Look at the last two photos in the post.) Of course you can easily fix that in Sketchup.
    Toy Thompson