While my proposed layout is firmly set in Texas in the late 40’s and early 50’s, I do like some of the more unusual and iconic boxcars and other rolling stock which were specific to other railroads in other areas (for example, the B&O wagon-top boxcars, and the Milwaukee’s rib-side boxcars). One of the cars I find interesting were the round-roof (or “turtle roof”?) boxcars that ran on various eastern and southeastern lines; I gather from what little I’ve seen that there may have been several slightly different versions of these.

It appears that the only versions of these are from Lionel and MTH Railking; from what I can tell, perhaps the Lionel version is more prototypical in dimensions and detail level than the MTH version. If so, I’m thinking about purchasing one and converting to 2 rail. To do so, I was curious about a couple of points:

1) Would the Lionel 2 rail conversion kit suffice to convert the wheels, or are there better choices for wheels and/or trucks to do so?

2) Which couplers would be the best choice, i.e., Kadees or another brand, and any particular stock number which is better suited to achieve this?

3) Also curious as to how difficult the conversion would be?

I know that these cars didn’t typically (maybe never) appear in freight consists this far south and west, but I know the B&O wagon top boxcars occasionally appeared in Texas: I have a book on the SP lines in Texas which clearly shows one in a mixed consist on the SP branch line between Harwood and Gonzales, Texas back in the late 40’s so I suppose anything is possible.

I believe Smoky Mountain Model Works or somebody else may offered a kit version some years ago but apparently it’s no longer available and I haven’t seen any offered on eBay, so not much out there in the way of choice, although I’m happy to be proven wrong.

Any thoughts or feedback would be very helpful, and much appreciated.


Original Post

The first thing to remember is YOU make the rules,  and pay the bills, so how closely you follow the prototype is your call. Do as you like/can afford.

Couplers....most use Kadees. The trip pin is supposed to represent an air hose, but it doesn't do too good a job of it. Protocraft makes a VERY  realistic type E coupler that can be operated with a magnetic wand or a cut lever if the car is so equipped. There are others....San Juan, Monarch... your call as to which.

I've seen several round roof box cars. Pretty sure Weaver made them and different brass importers had them made. Sooner or later almost will appear on Ebay. This hobby requires a certain amount of patience. Immediate gratification seldom occurs.

Go to some 2 rail shows if you can. Try and find back issues of the late "O Scale News 48/ft" and early issues of "O Scale Trains" magazines. The advertising within is a tutorial on what is "out there". Use the Internet and search engines.

Good luck!


PS: One last thing. Invest in some books with good photos of prototype equipment so you know what the real thing looks/looked like. There are a lot of bad models out there!

Last edited by Simon Winter

Smokey Mountains Seaboard Air Line Turtleback boxcars we’re in S scale only I believe, I know he hasn’t done O scale yet.

Zach Pabis, who has 3D printed the SAL 2028 motorcar in HO and O, has some data to do the SAL Turtleback car, but nothing definite yet.

Nobody has done a correct SAL car yet and they are not the same as the PRR or B&O cars. I have 2 of the MTH round roof cars and they are close to the B&O cars. I think the Lionel cars are close to the PRR cars.


If you are after a Pennsy X31 Round Roof box car, The Lionel model rivals anything in brass, with one major exception--the color is a "Tootsie Roll" Brown rather than PRR Freight Car Red.  They are easy to convert to 2 rail by either cutting off the couplers and using 2 rail wheel sets, or, as is my choice, to use Intermountain trucks.  Kadees or any other coupler brand are easy to install..there is a flat on the floor to accomodate them, but if I recall correctly you will have to drill and tap your own 2 mm holes for the box mounting screws.

If you want to super detail it, Dave Friedlander wrote an article in OST (#80, July/Aug 2015) that will help you

As for the paint, strip it in 91% alcohol and repaint with Zinc Chromate primer and add decals.  They should be readily available for both the keystone and ball herald:





Both decal versions:



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Last edited by John Sethian

Great stuff guys!

Some good news is the Lionel round top boxcars use the same under frame as their PS-1 boxcars and scale stock cars, so if you’ve done those, it’s should be easy to do a round top. 

I’ve heard Intermountain wheels fit in the Lionel truck frames. 




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PRR round roof cars are very different from B&O "Wagon Top" box cars.    The PRR car, whose design was used by 3-4 other roads, is a typical structure with traditional built up sides with traditional or typicla framing.    The only difference is that they made a rounded roof with the sides of the roof curved around to give more height inside.

The B&O car was only used by the B&O and is a very different structure.    The ribs start at the frame on the outside and go up and over the roof like a old conestoga wagon.   All the supporting structure is on the outside and it is quite different from what other cars had.    I guess it reduced weight and was easier to build than the other types.  

The Lionel round roof car is a model of a PRR X31 round roof car.    It is easy to convert to 2 rail.     I just cut the lionel couplers off the truck bolsters after disassembling the truck, and then replaced the wheelsets with Athearn wheelsets.    I think Intermountain or NWSL wheelsets could be used also.    Then I body mounted the Kadee couplers on the car.

IN my opinion,  boxcars from any road could show up anywhere.    Generally boxcars handled manufactured goods.    A lot of manufacturing was in the east so stuff originated there.    But it shipped all over the country, so boxcars from roads in the NE would have good reason to be in Texas or Calif.    A friend of mine has found photos of PRR X29 boxcars in Calif.

There are several Weaver B&O wagon top boxcars on e-bay right now. I just typed in "Weaver box cars" and 2 of the wagontops were on the first page. You'd have to determine the right lettering for your era. They are nice cars and pretty accurate. I have 3 of them on my railroad. Swapping out wheel sets on the weaver cars is usually pretty easy.

I've posted these photo elsewhere in the past, might as well post them here too.

Here's what the SAL B7 Turtleback roof looks like:

B7 end closeup

The ends don't have the small "darts" you see on the PRR cars:B7 end

Seaboard had single and double-door cars:model railroading 20

Here's what the PRR cars looked like, notice the small "darts" and the way the roof indents from the sides at the top:prr X31a 1prr X31a-end

Look at this beauty, love that style of lettering.  Looks like it's made of Hershey's chocolate:sal dd rr boxcar 11665


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At the Chicago this spring, I saw a brass Milwaukee round top car and I think it was a cattle car. Couldn't buy it as I had already spent my wad.


Thanks everyone for your responses and assistance.

Simon: Thanks for the encouragement. O scale shows are thin here in Texas (“thin”, as in “non-existent”), so not much to choose from in my region. I’m in no hurry to acquire one, so not a problem waiting to see if one appears, although I might get a Lionel version just for the exercise in re-wheeling it; and it looks pretty good to my untrained eyes. As for books, I have a couple of my dad’s books on freight cars, can’t think of the titles off the top of my head. I also have a Kalmbach book on freight cars of the 40’s and 50’s.

Christopher, I have an Atlas wagon top car already, so don’t really need any others, but I appreciate the information. Most of my stock is lettered for Texas lines; I just like some of the more unusual freight cars we didn’t usually see down here.

Jim, thanks for the info on converting Lionel cars; that will definitely come in handy when I go to converting one.

Bob, thanks for the pics on the different types of round roofs. I agree, the SAL car looks nice, although I prefer the single door versions.

Mario, that boxcar is superb, hard to believe it’s a Lionel item. I’ve never converted any Lionel cars myself, but there seems to be enough info provided by everyone to muddle my way through the process.

Many thanks again, gentlemen...much appreciated.

Bob, FYI:

the PRR x31 boxcar was built with both the stepped in round roof, or a flush roof sill round roof.


Thanks Chris!  I've only seen the flush roof once, I think Lionel does make a model of it, but I also think the ends have the small darts and the number of side panels are different, but again I'm not sure. SIRT had some really nice models he posted a while back.  They're also hard to find or were last time I looked.

Kyle,     Presuming you like the look of the rounded roof, Sunset/3rd Rail did a B&O rounded roof covered hopper in brass a few years back in 6 different road numbers.


Simon, I wasn’t aware that the B&O had round roof hoppers as well. Just did a brief search and found pics of them. I like it! Will have to keep my eyes open for one.

Thanks a bunch.


@Kyle Evans posted:

Simon, I wasn’t aware that the B&O had round roof hoppers as well. Just did a brief search and found pics of them. I like it! Will have to keep my eyes open for one.

Thanks a bunch.


To be clear, the B&O had "round roof" COVERED HOPPERS.

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