Re: N4 cabin car

O Fenton Wells

Excellent detail work Bruce.  Well done

On Fri, Nov 27, 2020 at 5:31 PM Bruce Smith <smithbf@...> wrote:

More N4 progress.

Getting to work on the floor/underbody, I started by drilling the holes for and adding the end grab irons. I also drilled 2-56 holes for the truck screws and 1-72 holes for Kadee semiscale coupler boxes. Note that the rear tab on the coupler box must be removed. Although it does fit between the center sills, there is a small step to the body that will not allow the coupler box to sit flat.

My car will have KD brakes. To the best of my knowledge, no underframe diagram is available so this will be "punt" based on what I could identify on the actual car (which was converted to AB brakes and then the brakes stripped off of it) and what the ND and NDA looked like. 

I started by adding the rest of the bolsters using 3/32" styrene channel. About half-way down the length of a piece between the bolster and side frame I made a vertical and horizontal cut to remove one corner. A pair of these were glued to each side of the bolster. Make sure that you make matching pairs, with the flanges pointed away from the other piece.  #74 holes were drilled on an angle through the center sill about 1/4 of the distance between the bolsters and the channels on one side of each bolster were drilled for the air line. The air-line was bent from 2 pieces of 0.019" brass wire and glued in place. A #74 hole was drilled in each end of the car for the air hose. Pieces of 3/64" styrene angle were used for the end braces. The "L" faces the center of the car, and the vertical web may need to be trimmed to fit under the air line. 

When a pair of Bowser 2A-F5 trucks was test fit, two problems became clear. First, I needed to trim away a bit more of the channels that make up the bolsters, since they interfere with the truck side frames, and second, the nice "L" end braces also need to be trimmed for wheel clearance. With the trucks and the couplers mounted, a quick test showed that the car matched a Kadee coupler height gage.

The F&C kit comes with several parts that are poorly or not described in the instructions, a set of levers connected by a rod, and another lever. My kit had a Tichy AB set included, but since I am doing KD brakes, that went into the reserve and I pulled out a Tichy KD set ("Disconnected K"). Looking at the F&C parts, I was able to identity the use for each. Part "A" is the support for the reservoir, part "B" is the support for the cylinder, and part "C" is the support for the lever that connects the brakes to the handbrake at each end of the car. After some arranging, I was able to settle on a location that appears to be close to prototype and glued the supports in place. You will notice that the reservoir and cylinder are on the same side as the brake pipe. I decided to do this based on a prototype ND system photographed by Jack Consoli (TKM 33). I was concerned that the brake line might get in the way, and I did have to trim just a tiny bit, but the side of the support for the cylinder fit into the flanges of the center sill, almost perfectly. 

A #79 hole was drilled in the back of the brake cylinder, offset towards the bottom (as a brake lever has to attach to the center of the cylinder back) and a matching hole was drilled in the end of the reservoir. The clevis was cut off the brake cylinder and a hole drilled where it had been. The holes in the brake levers to attach the rods were drilled with a #79 bit. 

The reservoir and cylinder were glued into position. With the two-lever set in position, the third lever was positioned and glued. The pipe between the reservoir and cylinder was bent and glued into place, and the two-lever set glued into place, with the levers nearly parallel to the floor of the car. 0.012" brass wire was used to make the rods between the levers at the business end of the cylinder, and between the levers and a hole drilled in the center sill at the bolster for the brake rodding. A piece of wire was used to form the single long hanger that was on the center sill encompassing both brake levers that were attached to the cylinder. Finally, the piece of pipe from the Tichy set that is meant to be the pipe from the air-line to the reservoir was used for that purpose, after slightly widening the end that snaps over the pipe, so it would fit over 0.019" brass wire. Wires were formed but not glued for the rods from the 3rd lever to each end for the hand brakes. These were left long to allow room to add the chain. 

The body was fitted back onto the underbody and the wood deck planking was test fitted. The bottom bolts for the end grab irons and a small piece of the trim next to the 1/4 round ends had to be trimmed away for the floor to fit flush. For the floors to fit between the body and the end of the car, almost 1 board had to be sanded away on the inner end (Careful! Don't sand the outer end, with the holes and handbrake ratchet!). Once they fit, they were glued in place and the handbrake ratchet and floor were drilled with a #77 bit and 0.016" wire placed in the hole. Make sure that you drill straight and that the bottom hole is in the thicker part of the end sill.

To add the hand brake chains and finish the brake gear, A-Line 40 link per inch chain was cut to about 3/8" in length. The end link was drilled with a #79 bit and then a #77 bit to open the link. A piece of 0.016" brass wire about 1" long was cut (this is longer than needed for the hand brake staff - remember it has to stick out under the floor a bit too!) and threaded onto the chain. The chain was glued to the wire about 1/4" from the end. The other end of the chain was drilled with the #79 bit and the long end of the 0.016" wire was threaded through the hole for the brake staff in the bottom of the car until the chain was just about to touch the bottom of the end sill. The free end of the chain was threaded onto one of the 0.012" wires that was formed to connect to the brake lever. In one of the photos, you can see this wire and the brake staff wires in their locations to show you how their positions. The wire was marked just long of where the chain reached when it was stretched almost tight. The wire was then bent at 90 degrees at that spot, the chain slipped to that spot, and then the wire bent almost complete back on itself. The free end was trimmed to about 1/16" and then crimped to form an eye with the chain in it. With everything in position, the chain should have a slight sag. If there is too much sag, you can either take up slack by twisting the brake staff, or adjust the bend on the rod where it goes into the lever. Both the brake staff and the brake rod were glued into place. The brackets for the brake shaft were carefully cleaned up, and the hole in the bottom drilled out with a #77 bit. The bracket was carefully slid over the bottom of the brake shaft and glued to the bottom of the car. The brake shaft was trimmed so that a small amount sticks out below the bracket. I think this finishes the underbody!

I'll move onto detailing the ends next!

Bruce Smith
Auburn, AL

Fenton Wells
250 Frye Rd
Pinehurst NC 28374

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