All Nation kit

if  you built the kit with the supplied full scale bolster, your only option is the Weaver Models Die Cast Truck [in 3 rail]. It is currently the only widely available 3 rail truck without a Bolster. All other 3 rail truck manufacturers have the Bolster built into the their truck design.

IF you can easily remove the full scale truck bolster from your kit, then you can use your K-line,Lionel, Mth, etc. truck types for 3 rail.

Try Weaver (www.weavermodels.com) or MTH (www.mthtrains.com). Ordinary 3-rail trucks don't work because their raised bolsters lift cars too high. All-Nation kits are designed for trucks with low, protoypical bolsters.

I drilled out a large hole in my All-Nation Observation car where the trucks mounted to the wooden floor, then fastened a 1" strip of metal (I think it was a HO metal weight) across the inside of the car.  I drilled a hole in each metal piece to mount the K-Line trucks.  This makes the car sit lower (by the thickness of the wooden floor).

Both PRRHorseshoecurve and Bob Delbridge are correct, based on my own experience.

Right now I am completing an old General Models Corp. (later, All Nation) reefer kit.  I'm having more fun than I can tell.  I LOVE building these old kits, jazzing them up with a few new parts (e.g., Grandtline AB Brake System, Keil Line door hinges, etc.).  But this one, with its incredibly fine bolster and reefer hatch  white metal castings is awesome.  And the Weaver diecast Bettendorf trucks with the diecast knuckle coupler bar is absolutely PERFECT to the car.  I only added a Kadee red fiber washer to the bolster seating area to provide a smidge of additional clearance to the diecast end sills.  Perfect!

Some time ago I built an old Athearn metal-sided ATSF Express double door box car.  I used Lionel Bettendorf trucks on that one, in which case I ended up ditching the wood bolsters entirely.  Again, a perfectly fine result. 

The Weaver trucks, though, are my favorites.  I only wish they had maintained the archbar style in their lineup.  Also, the Allied Full Cushion Express trucks are no longer available, another sad, sad situation....I would've preferred to use them on the ATSF Express boxcar as did some of the prototypes.

BTW, I have been told with some credibility that Athearn may yet make their old line of O-scale plastic trucks.  Re the archbar shortage, that would be GREAT news!! In fact, their O ardchbar trucks P/N is back-orderable through their sole distributor/owner, Horizon Distributors.  Although the wheelsets are for O2R, if you have square-top O3R rail (e.g., Gargraves, Ross, Scaletrax, et al) that may be OK as is.  Otherwise, I have been successful swapping out tinplate wheelsets for theirs.

I applaud you for building the old kits!!  You are part of a dwindling group continuing a dwindling part of this great hobby.  I have been consigned a quantity of these General Hobby Corp. kits for internet auction sale.  i'm torn.  I know I could never build them all, but I would if I knew I'd be around forever!!  There's also a GMC diecast Atlantic kit in the box.  Talk about a blast from the past! 

Please...have fun and enjoy the project!!

KD

When kit building or scratchbuilding I pick my trucks first as this will determine how I build the frame and bolsters.  The Weaver trucks will sit lower than many 'toy' based trucks. But construction the frame to use 'toy' trucks works well too. Just have to plan ahead.

You all are discussing a major difference between 2-rail and 3-rail.   Over the years most 2-rail mfgs moved to and followed the NMRA recommended practices for the coupler height, truck height, bolsters etc.    Therefore most (there are always exceptions) 2 rail trucks set the car height right on most cars with 2-rail scale body bolsters.

On the other hand, the 3-mfgs in their wisdom, have all gone different ways.   It seems they have gone out of their way to make their stuff different and incompatible with any other mfgs.   

It makes adapting 3 rail stuff to other brands or 3RS much more difficult than it should be.

I'm sure there are business models to support both plans.