I first wanted to work on completing the interior details before tackling the more delicate outside details. In this prototype photo (unknown source; found on the Internet) a tiny band of metal is shown around the interior rim of the car body (pointed to by the orange line). Interior shots of the GLa are hard to find, but several photos of models I have seen also show this strip.
I added mine using scale 1''x6" strip styrene, carefully gluing it flush with the top of the car's body. On the prototype it was probably part of the hopper's top cord, but I decided to build the parts separately. The loose strips you see in the hopper are for the next step.
Interior photos of PRR H21a hoppers showed another strip of metal covering the seams of the individual panels that made up the body. Since I built the body out of full sheets, these strips are purely cosmetic on the model. I again used scale 1"x6" strips. Note that they are on the opposite side of the exterior's ribs, starting with the first one and skipping every other one. In the case of the shorter GLa, there are only four needed. So, their location is determined by the location of the exterior ribs, which are clearly shown on GLa drawings.
As can be seen in my earlier photos, I have some gaps in my construction. I bought some gel superglue, which I carefully applied to those areas. On the sloped hopper bays I could use the bottle's tip (much like you would caulk with a caulk gun), but on the harder-to-reach areas I used a toothpick to apply a tiny dap. It worked well and it seemed to close up the gaps nicely.
Continuing with the interior construction, up next are the crossbearers. Below is a prototype photo of the interior of a PRR H21a (source unknown; I found it on the Web many years ago). The men are repairing one. I presume that since the H21a was built right after the GLa hoppers were built, that they are constructed in a very similar manner. If you look closely at the crossbearers, they appear to be made out of two sections. Each section has a center bulge and two lips. The lips of each section are riveted together to form the overall piece.
Before installing the crossbearers though, I cut and installed these "ice-breakers". I made them out of 0.020"-thick styrene sheet and sized them by eye.
The bent metal at the end of the prototype crossbearers is used to mount them to the side panel of the hopper. I am simulating that with a scale 8" square made out of 1-inch thick styrene. One is glued above the ice-breaker, and that one is then used as a reference to position the other two. This photo shows them clearly in the shadow. The left and right one are positioned such that they line up with the outside rib at that location.
The construction of the crossbearers came from fellow S-scale and PRR modeler, Bob Frascella. He responded to the previous photos I had posted on this page. I liked his idea so much that I copied it right away. Basically, the crossbearer is made out of a piece of 1"x8" scale strip of styrene, to which I glued a section of scale 4" angle strip, one to each side. The wide, open side of the angle is glued to the flat strip. This mimics the prototype just fine and it is easy to put together. No jig required. I then carefully cut and filed the crossbearer to length and then fit it between the plates I had glued to the side panels. The position of those plates is critical and I didn't do as good of a job as I should have, but it looks acceptable. I just need to pay attention to this step a little better the next time I make these cars again.
Here's a close-up photo of one of the crossbearers, so that you can see how I made it. It is simply a flat piece to which two angles are glued.