Lowering Intermountain 10'-6' IH box cars (e.g. 1944 AAR)

[mark.hinds]

I thought it best to do this in a new thread. 

On my N-scale layout, most of my SP box cars can be represented by the 10' IH 1937 AAR models from Intermountain, with various ends.  In addition, connecting roads have 10'-6” IH cars such as 1944 AAR types, modeled by Intermountain and Deluxe Innovations.  Unfortunately all these models are around 1 scale foot too high, so will need to be lowered. 

Based on the following typical dimensioned (but not scale) drawing, I hope to adjust 1944 AAR boxcars to be 15 scale feet railhead-to-top-of-roofwalk. 




I recently bought 4 Intermountain 1944 AAR-type models, decorated more-or-less appropriately for my time period (I will probably re-letter to “Ship and Travel”).  On these, merely thinning the roofwalk and lowering the underframe (or replacing trucks) won't work, per the image below.  Doing this to the extent needed to lower the car to 15 feet in height puts the underframe too close to the rail head.  The lowered car is on the right of the first image, with a blown-up detail of the lowered car in the second image.  Note from the blow-up that although the bottom edge of the side sill is pretty close to the correct 3.5 scale feet from the rail head, the bottom edge of the center sill is at only 2 feet above the rail head. 






Compare with this prototype photo below and the dimensions in the plan above. 



To summarize, what I need to do is thin the roofwalk (3 scale inches), lower the shell (5 scale inches), and lower the underframe (4 scale inches).  This would put the underframe at a bit less than 2.5 scale feet above the rail head.  So I need to lower the shell relative to the underframe.  Unfortunately, the underframe is cast in place with the sides of the shell.  (CORRECTION:  the floor is cast in place; the underframe itself is glued in place, but I can't break the glue joint). 

At this point, I see 2 options.  One is to remove the underframe and car floor and replace it with something else, which is a lot of work.  Another is to remove just the brake detail and file down the center sill by up to 5 scale inches (in addition to the 4 scale inch reduction of the bolster area).  Whether this will look adequate when viewed from the side is TBD.  It will look funny when viewed from below, but that doesn't matter. 

Mark H. 

[Missaberoad]

So you will be cutting notches into the ends? 

Can I ask what your aversion to body mounted couplers is? I must have missed it if it was explained before...

[nitpicker]Also remember it must be a car built after 1945 with improved dreadnought ends to be a post war AAR car otherwise it is a modified 1937 standard[/nitpicker] 

[wcfn100]

  Unfortunately, the underframe is cast in place with the sides of the shell. 

The IM underframe shouldn't be cast in place, it's a separate piece but glued.

And something that may be relevant here is that IM has been using the wrong underframe piece for the Modified 1937 cars since the beginning.  It doesn't fit properly causing it to bow down near the center.

Jason

[mark.hinds]

So you will be cutting notches into the ends? 

Can I ask what your aversion to body mounted couplers is? I must have missed it if it was explained before...

[nitpicker]Also remember it must be a car built after 1945 with improved dreadnought ends to be a post war AAR car otherwise it is a modified 1937 standard[/nitpicker] 

Yes, notches in the ends.  For some reason, they don't bother me as much as too-high cars; go figure.  The notches would be easy to fix later if I went to body mounts. 

I already use truck mounted couplers, which work fine.  It is possible that body mounted couplers would also work fine, but it is a lot of extra work, and I am a bit worried about coupling on curves.  I will probably buy a another Atlas PS-1 and experiment with this. 

You can't see it, but this model has improved dreadnought ends, per the prototype AT&SF boxcar class. 

The IM underframe shouldn't be cast in place, it's a separate piece but glued.

And something that may be relevant here is that IM has been using the wrong underframe piece for the Modified 1937 cars since the beginning.  It doesn't fit properly causing it to bow down near the center.

Jason

I own over 30 of the Intermountain box cars, mostly kits back from the 1980s when they still sold them, and all have cast-in-place floors/underframes.  Intermountain did this because they wanted to be able to easily use different roofs.  Buy one and look for yourself.  (CORRECTION:  Per MissabeRoad, the 1990s.  Yes, I'm getting old...). 

Mark H. 

[wcfn100]

, and all have cast-in-place floors/underframes.

Yes the floors are cast with the body, but the underframe detail is separate.  Depending on how much glue was used most of the undeframe can be removed pretty easily but there will be spots that require a bit of work.  The new models with the painted under side add even more hassle.




Jason

[mark.hinds]

Yes the floors are cast with the body, but the underframe detail is separate.

Jason

I just got out one of my 1937 AAR kits, and you are right.    

However, the issue with the featured model still stands, because it comes glued together already, and I can't break the glue joint.  I froze it for 48 hours, with no effect, so it's probably acetone.  The Intermountain guy couldn't tell me how their contractor glues them. 

The separate underframes will, however, make it easier for me with all the SP cars, which will be made from the 1980s Intermountain kits.  (CORRECTION:  1990s kits). 

Mark H. 

[Missaberoad]

Interesting... I will concede that body mounts can cause some issues with coupling on curves...
but with what you are planning to do I can't see it being any more work, you are planning quite a bit of surgery... lol

to add to the nits and make us all feel old (or young lol  ) the IMRC boxcar kits were introduced in the 1990's 

You can't see it, but this model has improved dreadnought ends, per the prototype AT&SF boxcar class.   

Excellent... as you were then 

Following along with interest... Have a soft spot for house cars no matter the couplers

Ive had mixed luck with Intermountain glue... Sometimes cars fall apart, other times I cant break joints to save my life...

[wcfn100]

However, the issue with the featured model still stands, because it comes glued together already, and I can't break the glue joint. 

I haven't done a ton of these, but it can be done.

Here's a Modified 1937 with the old underframe removed and a new underframe modified at the two center cross member to sit flush.



Jason

[bbussey]

Also, only the rods between all of the brake appliances are hanging low on that component.  The appliances themselves have a good vertical arrangement.  Replacing the rods and roofwalk with wire and etched brass/stainless respectively would reduce the distance the model would need to be lowered to reach your 15-foot threshold and maintain your 2½-foot under-clearance.

The cemented brake appliances component is difficult to remove, but I've never had an issue removing the centersill/cross-bracing component.

And also, the 13'11½" eaves height in the drawing is a far better constant to work with, because unlike the roofwalk there is no "extra-thickening" on that part of the model.

[bbussey]

Interesting... I will concede that body mounts can cause some issues with coupling on curves...

Depends upon the radius.  The 9¾" would be a problem.  Wider radii, not much or at all.  Of course, it also depends on the car length and wheelbase.  Bur if the layout has sweeping curves, it shouldn't be an issue.  I know 18" radius is not an issue.

[mark.hinds]

Also, only the rods between all of the brake appliances are hanging low on that component.  The appliances themselves have a good vertical arrangement.  Replacing the rods and roofwalk with wire and etched brass/stainless respectively would reduce the distance the model would need to be lowered to reach your 15-foot threshold and maintain your 2½-foot under-clearance.

The cemented brake appliances component is difficult to remove, but I've never had an issue removing the centersill/cross-bracing component.

And also, the 13'11½" eaves height in the drawing is a far better constant to work with, because unlike the roofwalk there is no "extra-thickening" on that part of the model.

If you look at the model view (right-most image), and draw a horizontal line across from the ruler, you will see that the center sill is 2 feet above the railhead.  This is easier for me because I have the original pre-Google image, which is 3 times larger.  I need the center sill to be almost 6 scale inches higher than in the right-most image.  This is independent of the brake detail.  I've already removed all underframe detail on my sample model, as well as the roofwalk and ladders.  I'll probably only replace the 3 pieces of brake hardware (triple valve, tank and ??), and leave out the piping, to be consistent with my other stuff.  The brake detail will be mounted slightly closer to the floor as well, though still within the range seen in photos. 

The reason I measure to the roofwalk instead of the eves is (1) my layout is almost at eye level, so the roofwalk matters visually, and (2) I can always get dimensions to the roofwalk, but not always to the eves. 

Mark H. 

[bbussey]

Mark, if you have an ORER for your era (and I suspect that you do), the eaves height above the rail is one of the columns of data for all of the freight categories.

[cjm413]

Yes, notches in the ends.  For some reason, they don't bother me as much as too-high cars; go figure.  The notches would be easy to fix later if I went to body mounts. 

I already use truck mounted couplers, which work fine.  It is possible that body mounted couplers would also work fine, but it is a lot of extra work, and I am a bit worried about coupling on curves.  I will probably buy a another Atlas PS-1 and experiment with this. 

You can't see it, but this model has improved dreadnought ends, per the prototype AT&SF boxcar class. 

I own over 30 of the Intermountain box cars, mostly kits back from the 1980s when they still sold them, and all have cast-in-place floors/underframes.  Intermountain did this because they wanted to be able to easily use different roofs.  Buy one and look for yourself.  (CORRECTION:  Per MissabeRoad, the 1990s.  Yes, I'm getting old...). 

Mark H.

Another practical consideration to keep in mind is that most new models are now designed for frame-mounted couplers.

Even if you don't like to replace existing models with new models (e.g. MTL PS-1 with Atlas PS-1), there are still plenty of prototypes out there that aren't currently available...

[mark.hinds]

Well, I was able to remove the glued-on underframe after all, by careful prying (1 broken rib).  Maybe it was CA after all...  Any opinions?



Mark H. 

[peteski]

Looks to me like melted plastic with bubbles. CA glue doesn't attack or melt styrene or ABS. Seems like they were using solvent (liquid cement).