I'm assuming that we are talking about the Mehano (Yugoslavia) 40' Steel Box Car (
http://www.spookshow.net/freight/yugo40box.html)
At one point I was trying to gather the info for our NTrak website that would have the prototype of most of the available N scale rolling stock. I never finished it since so many cars have so many different possible prototypes, but I do have some info on this car, although I won't commit to the accuracy since that is what killed this project in the first place. Surprising enough, most of this info came from Spookshows old website and I can no longer find it on his new site:
Years ago, I thought this was a Pennsylvania Railroad X-29 boxcar. Then I saw the beautiful Red Caboose brand X-29 and thought, no, no it isn't. But now, after careful checking, I find it IS a model—albeit 1970 quality- of an X-29 of a particular variation, from the bottom up to just below the roof, but NOT including the roof.
Some of the cars have one reefer ice hatch on each end the roof due to some confusion when they were being made. I also have a bunch of LL steel reefers that had this same problem (on those cars I cut the extra roofwalk off and cast some ice hatches to glue there so I could have a 'more accurate' steel reefer...remember, this was over 20 years ago and well before MT and others came out with a correct steel reefer).
Rivarrosi originally made this for Atlas. Then Rivarrosi stopped, and Mehano in Yugoslavia planned to make the same car for Atlas as a replacement. At one time it was also sold under Lifelike name.
The special feature of this car, which is shared by both the PRR X-29 and the NYC USRA-steel prototypes is the seam between side panels with the double row of rivets. This is where two side panel plates overlap, and the seam is riveted at both sides of the overlap.
Other features of the model-
NO fishbelly underframe.
Straight side sill.
10 steel panels on each side with double rivet rows
6 foot wide Youngstown steel (corrugated) door
Ajax brake wheel
Ladders (as opposed to just rungs)
Dreadnaught ends with 4-3 ribs.
Metal rectangular panel roof with 12 panels.
The model matches the major dimensions of the X-29. 40’6” inside length. 8’7” inside height.
The model is 10 scale feet wide where the prototype has an 8’ 9” inside width.
The prototype was built over an 11 year period 1923-1934 with lots of variations.
Panel doors versus corrugated doors.
Dreadnaught ends versus flat ends.
Vertical brake wheel VS Ajax end-mounted brake wheel.
The model in question corresponds to SOME x-29S...
except FOR THE ROOF.
The prototypes had metal roofing that laid flat with seams hardly showing.
I can’t find any listing that shows that these models were lettered for the Pennsy which they actually resemble, although Atlas once had them in Penn Central.
Except for the roof, this model corresponds to SOME prototype X-29s, especially those built between 1929 and 1934.
Still looking at the old old Atlas/ Lifelike X-29. It is a bit crude by the standards of recent models. However, it shares with other X-29 models the 10-panel sides, the double-rivet seams, the straight side sill and the overall dimensions of the prototype X-29, except for being a bit wide. It has an end “sort of” like a Dreadnaught end, and some kind of ribs.
If you want to model an X-29 with corrugated or Dreadnaught ends, this is the ONLY N model with “anything like” corrugated ends. They are not MUCH like any specific corrugated ends, but they give somewhat the impression, whereas the distinctive X-29 flat end really sticks out as something entirely different. So, this is a balancing act of one factor vs another.
Another way of looking at it, if you’ve got one or two of these cars, here is something they can be used for.
PRR #101763 Prototype Modeler October 1978 p.19
10-panel sides, Youngstowen-style corrugated door, Dreadnaught ends, Ajax hand brake.
PRR MOW #498040 Prototype Modeler October 1978 p.1,23.
This one has an end almost exactly like the Atlas/Lifelike model. Unfortunately, since it is in maintenance of way, it could only be used on a Pennsy layout, not in interchange service.
Erie Lackawanna #416024 Model Railroading April 1987 p.49
corrugated door, Dreadnaught ends 10 panel
That's what I have...actually I do have more but it has to do with how most of the RRs that the car came painted for never had anything close to this car and the one car that it should have come painted for - Pennsy, it was never offered. Hopefully that covered most of the question. LMK if there are any glaring mistakes since one day, I may actually put the info I have online...but only after getting a new flak vest.