Having already built one pilot model, I knew that this step was going to take a while. Three major components of the air brake system are represented on the model. These are the triple valve, the brake cylinder, and the air reservoir. Each of these components is assembled from two or three very small resin parts. I have to question the wisdom of designing the kit this way.
I suppose that casting these parts in resin was likely done to keep the cost of the kit down. On close inspection, these parts look blobby and vague when compared to the quality of injection moulded styrene detail parts. If I was only building a relatively small fleet for a home layout, say fifteen cars or less, I might opt to buy styrene parts. In fact, I had to substitute some Details Associates and Cal Scale parts on one ore car because some of the small brake parts had come loose from the resin sheet and were lost at some point in the distant past.
Our club has to eventually roster fifty of these cars, so building these fifteen ore cars with injection moulded styrene parts with more detail than the other thirty five doesn’t make much sense. Nor does it make sense to improve the detail on all fifty cars, despite the much simplified assembly that injection moulded parts would afford. I guess I’m whining a bit because it took so long to build parts that are passable in a large fleet, but don’t provide stellar detail. I’ll get on with it now.
The three components are: cylinder, reservoir, and triple-valve. The brake cylinder is comprised of three parts: the body, a cone on the end where the shaft comes out, and a dish on the opposite end. The reservoir has four parts: two halves of the tank, and two L brackets to secure it to the frame of the car. The triple-valve is cast in two parts: one that comprises about 3/4 of the part, and curiously, a tiny piece that gets glued onto one end. When comparing the part to photos of the prototype, the triple valve looks more accurate without the addition of the little bit on the end. As in most instances when I’ve been confronted with opportunities to make the car more accurate, I built the car the with the parts provided in order to simplify construction and make the fleet fifty cars consistent. Around a dozen of these cars were built at some point in the past, and I won’t be building the remaining unbuilt kits at our club, so that’s a something that I needed to consider when making a decision at a moment like this.
Before the nine parts for these three components could be removed from the resin sheet and cleaned of flash, I drilled #76 holes to anchor the air pipes that would be added later. The triple valve got three holes on the side facing inward, the reservoir got two holes on the side facing inward, and the brake cylinder got one hole in the end that looks like a dish. There are dimples to guide the bit in the reservoir. The holes in the back of the cylinder and the triple valve go where they seem most appropriate. After they were all drilled, I removed them from their sheets, cleaned off the flash, sorted them into piles, and assembled each component in turn.
After the tedious process of assembling the components, I glued one of each to all fifteen cars. That step in the sequence went more quickly.
There is probably an easier way to measure and bend the piping that goes between these components, but I approached it in a way that was easiest for me, given the tools and materials I prefer to use. I don’t have details of the actual routing of any of these pipes, but I think that what I came up with is a suitable representation of a network of air brake lines, based on drawings I have of other types of cars.
There are three pieces of air pipe that I built from .015″ brass wire: two that go between the reservoir and the triple valve, and one between the triple valve and the brake cylinder. The prototype car has more piping than this, but in keeping with the underlying goal of building this fleet cars like a terracotta army, I settled on representing these three important air lines.
I built one master for each pipe by trial and error. When I was satisfied that I had come up with something that was workable, I wrote down the dimensions of the sections between the bends. I unfolded the wire to measure its straight length and then chopped up fifteen similar pieces.
The first pipe that I built is the shorter of two pipes between the triple valve and the reservoir. Through trial and error, I determined that I wanted to build a z-shaped pipe with right angles. The overall length of that pipe is .800 inches.
I used a grab iron bending tool that is marked in thousandths of an inch to bend all of the pipes the same way. I made the first bend .350″ from the end. I made the next bend .450″ along from the first one.
I had to adjust the fit of the pipe to each individual car. There is some variation in the location of the three brake components on each car because there are no guide pins to locate the parts precisely, and there are limits to the precision of my skills to located them in a “freehand” way.
After I’d installed this first pipe to each car, I repeated the process for the pipe that runs more-or-less beside this one. This second pipe measured exactly 1 inch long overall. The first bend was done at .250″ and the second bend was done at .450″ from the previous bend. I made fifteen duplicate parts this way. Again, this pipe fit a bit differently on each car, but starting with the basic part already bent saved a great deal of time.
The third pipe goes from the flat side of the brake cylinder to the triple valve. This pipe is so short that it was a simple matter of cutting it from scraps left over from making the masters of the first two pipes.
In the next step, I’ll install the moving parts that include the clevis and the various rods and levers that transfer the movement of the brake wheel and the brake cylinder to the brake shoes on the trucks.