I have a fleet of Athearn Santa Fe streamlined passenger cars that all came with truck mounted couplers. I’m sure the from the factory with them so they would negotiate small radius curves. Since my layout uses a 26" minimum radius, I wanted to replace them. As many of you have found out, truck mounted couplers work fine when are cars are being pulled, but derailments can become an issue when pushing the cars, especially through turnouts. This is usually caused by the side pressure on the truck. Make a note, or better yet, take a picture of the car from the bottom to see where the coupler head is in relation to the end of the car.
The screws that attach the trucks are installed from the inside of the car. These cars use an interference fit to assemble the floor to the body. They slide into the car body. Sometimes it takes a little work to get them apart.
Once the trucks are removed, I cut the coupler arm off about 1/8" from the truck center.
Then I cut the couple from the arm almost flush with the coupler box. Save the piece that’s left over.
I cut that leftover piece, so that when it’s attached, it butts against he center sill that the trucks mount to, and is flush with the end of the car.
Making sure to center the piece, I glue it to the bottom of the car with CA. I use slow setting CA to give me time to center it, then brush on a drop of Zip Kicker accelerator.
I add a small drop of the CA to the coupler box and glue it to this piece. This is just to hold it in place while I check the coupler height with my Kadee coupler height gauge.
If anything, the coupler is usually too high. I just shim with styrene pieces until the height is correct.
If the height is correct, I remove the coupler, and usingthe picture I took earlier to align the coupler,cement it in place permanently. You could also use the Kadee draft gears and drill, tap an
I would recommend not using CA accelerator. Just be patient and wait for the CA to set naturally. The accelerator makes the CA joint more brittle.
I always go with the Kadee draft gear, and drill-and-tap for mounting if I can. The draft gear boxes are very cheap. Drill-and-tap lets you replace the coupler easily if necessary. Of course, if you’re using Kadees, the couplers will probably outlast the car, your layout and you.
Mr. B, thanks for the advice on the accelerator. And, you’re right about the Kadees, I have NEVER had to replace one. But, every piece of rolling stock/motive power gets one installed on them. Especially those plastic lookalikes. Yecch!
I just recently installed kadee couplers to the frame of my HO passenger cars. What i did was measured the distance from the frame to the top of the old talgo coupler which came out to slightly less than 1 scale ft. I then took Evergreen .030 styrene sheet and cut it to the same deminsions as the kadee coupler box plus 1/2 scale feet on one end. It took 3 pieces of .030 styrene to fill the space between the frame and the top of the talgo coupler. Once i had my measurment, I cut off the coupler arm from the truck with a razor saw and discarded the talgo coupler arm.
I then stacked the 3 pre-cut pieces .030 styrene together and added the top portion of the Kadee coupler box and then glued them with MEK (Methyl Ethyl Ketone) to the frame ensuring that they were lined up dead center to the middle of the frame and protruding past the frame about 1/2 scale feet from the edge of the frame. Once the MEK dried, I then took a drill and drilled a tiny hole (I believe i used a #41 bit but not sure) thru the styrene and into the frame and then mounted the rest of the coupler assembly using a small wood screw that was long enough to penetrate the kadee coupler assembly, 3 pieces of styrene, and the underside of the frame. I used the Kadee #46 (long center shank) couplers on the “A” end of the passenger car and a #5 Kadee coupler on the “B” end. The longer coupler has a longer swing radius than the # 5 when the cars go around a curve so that they won’t pull the truck off the track when in a curve. Once I tested the assembly, I painted the white styrene and the Kadee coupler box with Floquil’s grimy black.
So far the body mount coupler is working very well. The secret to backing a passenger train is to do it very slowly.
This thread reminds me that one of the updates I need to perform (and have been putting off) is to replace the truck mounted couplers on my Rivarossi Budd streamliners and replace them with body mounted Kadees. I still need swiveling action as they will have to negotiate 24" radius curves.
Yes, I know that might not be prototypical, but I have to work with the space that I have.