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Peter's Model Railroading | Articles | Rolling Stock | B&O M53
Construction: Underbody


The main focus now is to start building and detailing the underframe. After cleaning off all the flash from the centersill, I cut and trimmed the thin pieces of material that are to be glued into the slots in the centersill. The lines in the photo show where some of these go. Most of these filler pieces were too wide and had to be filed down to fit their slots. There are four small, square ones and two longer, rectangular ones for each side of the center sill.

The next photo shows all these pieces glued in place and filed to match the profile of the centersill. I used superglue to install them, but a number for them came off when I started to file them to size. I used 5-minute epoxy to glue those that came loose.

The centersill is then ready to be installed into the underframe. The kit's instructions say to use superglue, but I preferred to use 5-minute epoxy for this step. The reason being that the centersill needs to be perfectly centered lengthwise on the car. The epoxy buys you some time, whereas superglue is instantly permanent. I used a caliper to make sure the centersill stuck out from the underframe an equal distance on both ends. Also, I put the assembly on a sheet of flat metal to make sure the assembly was perfectly straight when the centersill was glued in place. The next photo shows a set of metal weights used to hold the centersill down while the glue is drying. When installing the centersill, try to make it centered across the car width-wise also. The step after this will insert some parts between the centersill and and the bolster cap plate web. I did not do that, and it made the next step more difficult.

The next step is to install four bolster/centersill gussets. There are six of them supplied with the kit, but you only need four. They require a lot of filing, fitting, and trimming to get each to fit correctly. The photo shows one of them trimmed and shaped to size to fit in the slot on the underframe nearest the part.

The first one is glued in place in the next photo. I followed the kit's instructions exactly for the gluing. Unfortunately it sits up too high, which I had to file down later on.

The next step was somewhat unclear in the kit's instructions, but there are some small strips of material with a row of rivets cast on them. These need to be glued across the centersill on the cross-bearer. There are four of them. Again, not entirely confident of my accurate placement of these tiny parts, I used 5-minute epoxy rather than superglue to glue these in place.

I followed the kit's instructions to drill #50 holes in the bolster, bolster cap, and underframe for the truck mounting screw. The next photo shows how I lined up the bolster cap part with the solid ends of the #50 and #51 drill bits after I placed 5-minute epoxy on the top of the bolster/centersill gussets. The ends of the part will be glued later.

Since I used 5-minute epoxy I had to wait for the glue to dry and make sure that during that time the two parts didn't move and stayed perfectly perpendicular to the long edges of the car. I used four metal weights to weigh it all down. It was a bit of a careful balancing act, but it worked.

The instructions state to form the outer lips of the bolster cap parts to fit the underframe's bolster cap plate web using a butane torch. I bought one of these about 10 years ago (from Micro-Mark, I believe), and after I bought it I couldn't remember why I had done so! Well, it came in handy today, because I was able to use the torch to soften the parts just enough to make them conform to the bolster cap plate web.

Two or three very quick bursts from the torch were all that was needed to soften the material. I then quickly placed my finger on the part to make it conform to the bolster web.

After I had "melted" them, I used some superglue to permanently attach the "flaps" to the bolster cap plate web (as shown in the next photo). I used a file to make the edge of the plate flush with the sides of the car (not yet done in the photo).

The next step is to start working on the main air brake line. The line is supposed to go through the bolster cap part web on one end of the car, through the next cross bearer, and then flip over to the other side. On the other side it will do the same, except that it goes through the remaining three cross bearers. To distinguish one side from the other, look at the tabs that will eventually hold the valve attachment supports (identified in the next photo). That side of the centersill will have the air brake line go through three cross bearers. The two circles in the photo show where I have already drilled the holes through the parts on the other side. The wire in the photo is just to help line up the holes to drill. I used that wire (with some permanent marker ink at its tip) to identify where to drill the next hole. Since our drill bits are too short, I drill the hole from one side and then drill it again from the other side of the web. That way the hole will take the wire straight through.

The next step was to install the L-shaped valve attachment supports onto the ridges identified in the photo above.

I then cut and shaped the green florist wire that comes with the kit into the shape shown here. This is the main air brake. I tried to get the whole wire through the whole car, but it was just too difficult. The cut was made so that it is under the valve attachment supports, so that it is hidden from view later on.

The other side of the brake line is just a simple straight section of the green florist wire. I then put a small drop of superglue where each of the wires run through the underframe parts.

This next photo shows quite a bit of work done. The next step from above was to install the long L-shaped pieces. I accidentally used the wrong parts and moved along. When I started gluing the valve and other parts I realized I used the wrong parts. I was able to remove them. I then glued the L-shaped parts you see here and re-installed the valve parts you see in the photo. I needed to put a shim piece of styrene (I believe it was a 0.040" thick piece) on the L-shaped parts that are the valve attachment supports to have the valve sit at the right clearance. As per the instructions, I drilled a hole in the valve for the future wire before gluing the valve in place.

I completed the installation of the brake levers, and the glued the grab irons over them. They were a bit tricky to keep in the right position while the glue was being applied.

I could not for the life of me figure out how to attach the wire that goes between the brake levers. The part sprue that is shown in the upper left corner of the photo look like turn buckles, but the kit's instructions show parts that are similar to what you see on one end of the valve (I don't know what that part's name is). Since those parts don't seem to be included with the kit, and I didn't have them, I decided to just let it go and glued the wires directly to the brake levers. I'm not sure that the detail would be visible from a normal viewing angle anyway.

Next up is the reservoir. This close-up photo shows the two holes I drilled before I installed the part.

I cut and trimmed to fit two 0.020" pieces of styrene upon which the reservoir will rest. I then superglued those to the underframe, and glued the reservoir in place after that had dried.

The "triple valve" part in the kit (which is what I presumed to be the part shown in the next photo) is next. It doesn't look a thing like the part shown in the instructions' photos. But by deducing all the other parts left in the kit, this is the one I picked. :-) I drilled three holes on the inside-facing side as per the instructions (see two photos down for the approximate locations of the holes). This, too, requires a small piece of 0.020" styrene upon which the part is glued.

I then glued the wire between the valve and the truck bolsters. The one attached to the valve requires a small section of chain. To glue that chain I held it in a pair of tweezer by one link and applied superglue. This connects all the chain links together and keeps them in a straight line, which makes them easier to install to the wire and the valve.

There are now three wires that need to be connected between the various parts. I installed the wire between the valve and the triple valve parts first. It was mostly a bit of trial and error to get them to the right length and be of the right shape. There are two wires between the triple valve and the reservoir. These were a bit of challenge to get in there. Update: I did not install the triple valve correctly; The five holes visible on the top should have been facing in toward the center of the car. I highly recommend consulting the "Modeling AB Brakes" article by Ted Culotta (Railroad Model Craftsman, August 2003, pg 80).

The details are finished for the underframe. I want to go ahead and paint that first before moving on to the next step. I think it will be easier to paint it now rather than wait until it is installed. The photo shows the underframe airbrushed with Floquil's "Grimy Black". It has just the off-black color I was looking for. This was the first airbrushing I had ever done, and I am happy with the result (it is more black in real life than it is in the photo; the photo is slightly over-exposed).

The interior of the car needs to look like wood, so there's nothing that looks like wood than wood. I don't know if in the final model the interior will be visible, but just in case, I covered it with wood. I used N-scale 2"x8" strip wood for the flooring. I started gluing them down one by one using superglue, but that was very time-consuming and tedious. The method I settled on was using 5-minute epoxy. I spread it very, very thin with a flexible piece of styrene. I did a small section at a time and placed the boards on top of the glued surface. I then placed some metal weights on them and let it dry for a while. When all the boards were down, I flipped the car over and sanded the boards on a sheet of 320-grid sandpaper on a very flat surface. This got rid of any glue globs and made all the boards the same height. After removing the dust, I stained the boards with Minwax' Cherry stain to yield the result you see in the photo.

With the underframe mostly completed, I could now install the trucks. I first used a tap to tap the hole for 2-56 screws.

I could then install the truck. The truck is just a stand-in until Jim King produces the correct truck for this car (if ever!).

And here's the car on the track.

I gathered up all the parts that would eventually make up the one car and put them on a digital scale. For the length of the car, it came up about one half of an ounce too light. I then broke off and installed two 1/4oz weights to the ends of the inside of the bottom of the car. That should minimize their visibility should I model the car with the doors open. It now measures the correct weight.