The instructions tell you to start working on the body details next. Before I started that, I first cleared of all the debris left in the door openings. I also sanded smooth the area on the door bottom where the part broke off. Finally, I used the Dremel tool with a sanding cylinder to carefully sand off the big blob of material on the inside roof. That probably wasn't going to be visible during normal operations, but I wanted to make sure.
To install the grab irons (two per side), I cut a piece of 0.030" styrene to the inside width of one of the grab irons and used that to hold them approximately two scale inches above the body, while I applied superglue from the inside. The mounting holes for the grab irons are clearly marked.
Together with the pre-marked holes and the styrene strip, you wind of with nicely positioned grab irons. In the real world these things get beat up and bent and abused over time, but I find that a model looks much nicer when they are straight; just a personal preference. By they way, in retrospect, I would recommend drilling all the grab iron holes before installing the first grab irons (see further below), because the car's body will have some pressure exerted against it while the remaining holes are drilled.
The next step was to install the door guide rails above the doors. The hard part here was finding the parts in the box!
There are a large number of grab irons for which we need to drill holes next. The ones for the ladders are tricky. Rather than using a drill press as the instructions suggest, I used a brass bar or a metal ruler against the edges of the ladder to control the drill bit, as shown in the next photo. These are challenging to do and require some patience. What you do is you press the bar or ruler very firmly against the ladder rib, and then press the drill bit against the metal bar or ruler. This keeps the drill bit in the correct position while you drill down.
The next three photos show the various holes that need to be drilled. The instructions are good about indicating where the location of the holes are.
The 3/4-view of the car shows the what seemed like hundreds of grab irons that had to be installed. This is the brake end. The other side has the same number of grab irons. It was a lot of tedious work, and I'm glad it is done. I wound up not using the supplied jig for making the grab irons. It was just so much easier to just use a small pair of needlenose pliers.
The next step was to install the brake gear. The parts needed for this section are not marked in the instruction document. The instructions at the top of page 8 make absolutely no sense whatsoever. I had no idea to what the paragraph was referring. If you don't know the prototype names for the parts, you're lost. I was! On top of that, some of the parts in the photos in the document don't match the ones that come with the kit. The next photo shows the brake wire/line that needs to be shaped to fit the car's end, and the part into which it ties at the bottom of the car. I shaped the wire and made it long on both ends, so that I could trim it to fit.
I deduced the parts for the top end of the car. The brake wheel housing is easy to find. The other part to its left didn't match anything in the kit based on the photos included with the instruction document. I just grabbed a part that somewhat resembled it, and hope that I don't need it later on! Next, I glued the two parts shown in the photo above into their location. I glued the center location of the wire first, and then, when dry, I cut the wire to the right length and glued the ends in place.
My kit didn't have the brake platform in it, so I decided to scratch-build one from wood. I used some thin N-scale wood strips (I think it was scale 2x10) and glued them to a piece of clear styrene for strength. When this was dry, I superglued the platform to the car. Also shown in the next photo is the strip of rivets glued horizontally across the car's ends. Both ends need a strip. I followed the photos in the instructions. I could not make out from the text in the discussion whether this strip was to be included if modeling an M53 (as opposed to an M53a).
I cut a length of chain (supplied with the kit) to the approximate length needed, and applied superglue to make the chain straight and manageable. After I glued the chain in place, I also cut and glued in place a piece of wire to represent the piping going down to the brake fulcrum.
The next step was to trim and install the roof walk. I used 5-minute epoxy to glue it down to the roof of the car, so that I had some time to make sure it was centered across the car in both directions. Some metal weights were used to hold the roof walk down while the glue dried. Also barely visible in this photo are the tiny pieces of styrene that are to be glued to the top of the ladders and the single grab iron above it. I had done the ends in this photo but had forgotten to do the same thing for the ladders on the car's sides. Those were done later.
The roof walk approaches require a grab iron. It takes a bit of trial-and-error to get it to be the right side and shape. The "lip" on the left side of the piece fits under the roof walk and provides the glue surface to the roof walk. I used superglue to glue it in place, by placing the glue on the lip and then using a pair of tweezers to squeeze it to the under side of the roof walk.
Up next are the tack boards on the ends of the car. I had to file the rivets off of one of the rivet strips to get the tack board to fit. I might be easier, in retrospect, to just not have the strip go all the way across the car. I don't know why the documentation states to do that for one end and not for the other. They are both identical anyway.
The brake wheel was added (it took me a minute to figure out that the brake wheel was inside of a rounded piece of sprue!).
I drilled a hole for the brake wheel shaft, and superglued it in place. It was a bit of a challenge to get it to stay on straight.