Most large cardboard manufacturing plants receive corn starch by rail. My Packaging Corporation of America plant is no exception. Starch is used as an additive in the adhesive that holds the layers of corrugated cardboard together.
On the Gettysburg & Northern Railroad, we delivered starch to Inland Container (whom my PCA facility is loosely modeled after) in 100-ton ACF Pressuraide hoppers like no. 51029 pictured below:
Now Atlas makes a beautiful Presssuraide hopper in HO scale, but has yet to produce it in 1/48. However, Lionel makes a very well detailed ACF 4-bay; complete with see-through metal walkways, separate grab irons, and nicely done brake gear:
I obtained two of the Lionel SHPX cars, which are very easy to convert over to 2-rail. Northwest Shortline #8293-4 (36" / 145 tread) wheelsets are drop-in replacements. Not only is the conversion easy, Microscale Decals even offers an O scale decal set for CCLX Pressuraides. You can view the decal set here: Corn Products Decals
I considered kitbashing the Lionel car into a Pressuraide, but quickly dismissed the idea as too much work. The pneumatic outlets of the Lionel car are close enough for me! A few hoses for transferring starch from the hoppers into my PCA mill and I'm all set. PCA will receive a hopper of starch about once per week. So two hoppers will serve my needs quite nicely.
Spending most of my free time on layout construction, I contacted Jeff Sohn to see if he would be interested in painting and decaling these cars for me. Jeff did an AMAZING job on these! If you need a model painted, I highly recommend Jeff's work. And be sure to check out his website: Jeff's Custom Train Painting
Here are pics of the completed models. I need to add couplers and a little weathering, then they will be ready to start earning revenue for the NCIR.