Cut the sheet to length and width for all three roof sections. Be sure to allow for enough overhang on both sides. If each layer contains at least two pieces, make sure the joints on the top and bottom don't fall one directly above the other when we laminate them together later; make them overlap. We'll be bending and gluing the roof over balsa wood ribs.

Ordinarily balsa has little application in railroad modeling but this is a case where we might be open to new materials and ideas. I used balsa because it is hard enough to do the job and soft enough to cut and work easily into the male and female forms in Figure 1. Cut 1/8-inch balsa sheet into at least 9 half-inch strips, each 4 1/2 inches long. You'll need at least five for the caboose itself and four more later on. Use an extra copy of the caboose plan as a guide to cut the outline of the roof's inside surface; then use the piece you just cut as a marking guide on each balsa strip to outline the roof curve. Use a sharp razor blade to slice the number of forming ribs you want from the balsa strips. Hold the razor at a high angle and make the cut in several passes. Keep in mind that we want both the rib and the strip intact. You'll find out why in a moment.

PERMANENT ROOFS

First let's cover how to build a permanent roof. Mark the top of the cabin sides where the ribs will go and set the ribs in place without glue. Put a thin line of glue along the top (curved part) of each rib and lay on the bottom roof sheet, scribed side down. Be sure you have positioned it correctly, then coat the top of that sheet with glue and lay on the upper sheet, scribed side up. Be sure that alignment is correct, too.

Lay the female strips from which you cut the ribs (Part B) curve-down on top of the roof. They will force the roof to hold its curve while the glue sets. Put some weights on the female strips and let everything sit a good while. The idea is to be sure evaporating moisture has no chance to cause the wood to distort even after the glue has set. Follow this procedure with both cabin roof sections. The cupola roof needs no ribs.

Next, the roof end beams. Soak two pieces of 1/8-inch square lumber about 6 inches long (or four, if your roof will be removable) under water for a few hours. When the wood seems pliable, work a curve into the pieces about equal to the roof curve. Then, as in Figure 2, sandwich each piece between the extra male-female forming ribs and clamp them well. Let everything dry for at least several days.

DETACHABLE ROOFS

If you prefer a detachable roof, you'll need to complete a few extra steps. Cut two 1/4-inch square pieces of wood long enough to fit between the cupola and the car end. Clamp them to the inside of the car side top beams. Glue the male forming ribs (Part A) to the 1/4-inch pieces but not to the car side top beams. Add two more 1/4-inch pieces between the ones you just installed. That gives a strong rib-to-beam bond. Lay down the roof sheets as above.

Make two extra roof end beams, as I pointed out above. They will go inside the visible outer end beam, where the ladders attach. The reason? The outer end beams will attach to the cabin by way of the fascia board but not to the roof. The second (inner) end beam will attach to the roof in order to maintain the proper roof curve and butt up against the outer beam.

Add the curved outer end beams when you add the roof ladders. That's so you may mount the ladders absolutely vertical. Clamp them well while the glue dries, and be sure they are in the correct position, especially the roof corners. Although you can't see it, I put 1/8-inch square stock between the cabin corners and the roof end beams to give some extra strength to the fascia boards. I also put some just inside the end beams to give more substance for the pins holding the top of the ladders, and underneath the roof where the roof end grab irons poke through.

COVERING THE ROOF

The Rio Grande's cabooses had canvas roofing. Other wood cabooses used tar paper or sheet metal. I like tar paper, so I strayed from Rio Grande practice. The material I chose to represent that material was 400 grit waterproof, wet or dry, silicon carbide sandpaper. The texture seemed about right for my model and the color provides a very realistic base for weathering.

You could either put on the paper in once piece, as canvas, or in strips, as roofing paper. If you use strips, they should be 1 1/8 inches wide but shorter than the whole roof. Since three widths won't quite cover the roof, I also used one or two narrower strips.

Either way, fold both an end and a side down 1/16-inch at a ninety degree angle, as in Figure 3. That's a critical dimension because if it's too short the roof edge will show below it; if it's too long you'll have a heck of a time trying to trim away the excess!

The sheet is supposed to start at one corner. And on a curved roof such as ours, you'll have to slit the folded end every 1/4-inch or so to help it conform to the contour. Where the paper flashes against the cupola, remember to fold up, not down.

Spread a light but even coat of glue on the underside of the paper and be sure it reaches all the edges. Lay it on, snuggle it in just right, and hold it with your fingers until the glue sets enough to grab. You'll probably have to keep re-pressing the folded part, and expect it to be a messy, time consuming operation. Glue will get on your fingertips and the roofing no matter how fastidious you try to be. Don't worry. When the glue has set up a bit, rub the paper with a stiff toothbrush or a wire brush. It'll be fine.

Overlap the next piece about 1/8-inch as Figure 3 shows. Do both sides in that manner. The center of the roof goes much more quickly because there are no folds. Just be sure the inside sheet (higher up and closer to the middle of the roof) overlaps the one lower down so water will roll off the roof and not into it!

THE ROOF WALK

I built my roof walk supports as custom pieces to be sure they fit the roof well. Cut each support (the cross members under the long planks) to length, then sand or file the underside to the contour of the roof. Be sure they don't rock. Then cut the boards to length.

I suggest gluing each brace to one board: Lay a board upside down, pencil on the brace locations, and put a spot of glue on each. Be careful to arrange the supports in exactly the same order as you fit them to the roof and glue them to the board. Next add the other outside board. Finally, the middle one. When the glue is dry, paint the entire assembly the same color as the caboose body. After everything dries, glue it in place.

You may buy end brackets or buy them. I used commercial castings. You may choose from Ozark Miniatures' OM-17 Catwalk End Brackets or Shortline Foundry's 5071 Roof Walk End Braces. If you make them, use .032 brass, cut and form the strips, and epoxy them together.

THE RETAINER VALVE

The "B" end of the car, the end with the cupola, had a brake retainer valve. Again, I used a commercial casting and the choices are Ozark's OM-16A BRV and Shortline's 5053. Drill out the end to receive one end of a .046 diameter brass rod and the center sill to receive the opposite end. Be sure to space the hole as far from the cabin wall as the valve so the rod will run straight down. I used epoxy to hold everything in place. Since we still haven't installed the end platform floorboards, I slotted one board for the brass rod in anticipation.

GRAB IRONS AND RAILINGS

Rio Grande cars generally used rod about 3/4-inch in diameter for grab irons and railings. We'll have to make our own curved side grabs, right-angle end grabs, and end platform railings. For the straight grab irons on the end sills and the roof above the ladders you may use Shortline Foundry's 5041 or Ozark's OM-10 offset grabs. Shortline's are formed brass (neither cast nor white metal) if strength is a factor in your thinking.

For the rest, we'll use .028-inch brass rod, a scale 5/8-inch in diameter, and bend it to shape. The best tools for that are needle-nose pliers, one modified, one unmodified. Modify a pliers by grinding about 3/32-inch from the end of one tine, and shaping it as in Figure 4.

To form a grab, hold the very end of the rod in the modified pliers and twist the pliers to wrap the rod around the ground-down end. Make as full a circle as you can. See Figure 5. Reinsert the pliers in the loop and bend back the rod as in Figure 6. If the loop seems too big, squeeze it in slightly.

Use a marking pen to draw a line across one jaw where the width is 1/8-inch. Figure 4 shows how. That's the spot we'll use to bend every vertical. Then insert the bent loop a short way into the pliers and bend the rod 90-degrees, as Figure 7 shows.

Bend the first vertical as in Figure 8. The grab is now half done and we'll do the remaining bends in reverse order. Lay the rodding flat on the drawing to determine the correct length of the next bend. When you bend the rod, be sure it is both vertical and in line with the original bend. Clip off enough excess wire to allow yourself to work comfortably, then bend a loop just like the first one. It will take a little time to get it right. Finally, align the second loop with the first and make whatever adjustments you need to be sure the grab is true and square.

The four irons on top of the cupola are a little more complex because they're L-shaped. See Figure 9. Just make the top section twice as long as a straight grab, then bend it 90-degrees at the center. And don't worry about that third leg. Make it as a separate piece. Altogether the car needs eight. If you make the vertical part slightly longer than it should be you may position it, trim it to length, then position it carefully. Soldering is unnecessary. A drop of CA (super glue) might make you feel better. The four large L-shaped grabs on the car ends are virtually the same as those on the cupola roof. Just remember one leg is longer than the other and each is a mirror image of the other. If you want to put a radius into the L-bend, use a nail, a screw, or a piece of rod as a guide instead of the square edge of the pliers.

The long, curved side grab irons involve a couple of changes. The loops on each end are aligned differently, so again you'll need right- and left-hand versions, two of each. I find bending a radius large enough for those parts is easier if I do it by hand, rather than wrap the rod around a hard object of the right size.

The railings are last. The real caboose railings went from round on the vertical part to flat on the horizontal. Shortline Foundry may have correct versions available by the time you read this. Otherwise, you'll have to build your own and they go together pretty much the same as everything else. Do note that the railing on the ladder side attaches to the ladder. The best way to accomplish that is to solder the parts in place. If you make your own railings you also may want to flatten the tops on an anvil.

I painted all the hardware before installing it but after soldering. As I said last time, the correct color could be boxcar red, black, white, or silver depending on what era you're representing. Mine are silver.

THE LADDERS

Shortline Foundry offers a set of caboose ladders (part 5060) and most of you will be a lot happier if you buy them. I decided to do them myself. (How do you suppose I earned my nickname?) For me, the result was worth the effort.

I used brass strip and rod. It has to be fairly rugged so I decided a little extra mass was a reasonable compromise. The sides are .032 x 1/4-inch stock; the rungs .046-inch rod. Yes, I realize the sides are too wide, but the top needs that width to accommodate the double sets of pins attaching it to the roof. So we start wide, then reduce it where we have to. Figure 10 shows what I mean. Besides, it's a lot easier to work with a larger piece during assembly.

If you use my so-called "sacrificial" technique, you'll be able to keep the rungs absolutely parallel and centered correctly in the sides. We'll stack the flat stock, and glue it together with an extra length we will cut off (sacrifice) later. Even if you buy ladders, remember this technique. It is useful anytime you need flat parts shaped or drilled identically and it applies to metal, plastic, or wood.

If you use flat stock 6 inches long you'll have half an inch at each end to sacrifice plus a little more for final trimming to fit. Here's how: Clean the last 1/4-inch of each end of the strip. Stack the strips one above the other and epoxy the ends together. Clamp until the glue sets. (You could also use solder.)

Carefully mark the location of each rung along the top strip. Lightly center punch each point, being very careful to center the punched mark on the strip. Drill the rung holes with a #56 bit using a drill press if you have one. Then saw off the epoxied ends. Figure 11 illustrates this step.

To assemble a ladder, make two spacing blocks out of 5/8-inch thick wood. Clamp the side strips to each side of the spacing blocks as in Figure 12, being sure to keep the blocks at each end well away from the blocks. Slip the rungs into the holes and, by keeping the clamps just slightly loose, maneuver the side strips around until the sides and rungs are in perfect alignment. Then tighten the clamps and solder. Use a good size iron; it will let you do each rung so quickly the heat won't have time to travel back to the last solder point. I suggest using a wet rag to keep the previously soldered section cool. Mr. Micro's treatise notwithstanding, ordinary low temperature solder should do. Just use as little solder as possible.

Next, file away the excess solder. Then, the excess brass stock. Use a straightedge to put a line on each strip marking what material stays and what goes. Figure 10 should help. You could use a Dremel tool with a grinding attachment, but I found filing by hand is a lot less stressful on the parts and allows much more control. I did the rung section and the bottom first.

When you bend the bottom angle, be sure to do it evenly so the ladder stands straight. After the roof end beam is permanently in place, carefully file the top section to fit the roof end. I used two needle nose pliers to make the top twist, then drilled holes for 1/4-inch escutcheon pins to attach the ladder at the top and bottom. The correct bit is a #70 (.028-inch). And remember to pre-drill pin holes in the end sill.

Now is also the time to drill a hole for the end railing to fit into the ladder side. You'll also need a corresponding hole to attach the hook for the center chain. Figure 13 shows how to attach that hardware. For the hook, use whatever size wire the loops of your chain will fit. Just in case you may have overlooked it, the ladder and end railings should go on after you add the hardware to the car end or you'll have a heck of a time getting in there to drill holes and mound grab irons.

NEXT TIME

In the next issue we'll finish our caboose, adding the remaining hardware, lettering, clear coat, and window glass. In the meantime, the projects in this installment should provide you with more than enough to do.