This post explains the steps I used to convert a die-cast Lionel ATSF PS-4 flat car to 2-rail using Kadee couplers & Atlas Trucks.
This procedure is not the most direct way to convert this car & some members may have used easier ways to convert these cars. This is the first Lionel car that I converted & I made many mistakes along the way which forced me to use a rather complicated procedure to achieve the end result.
I bought this freight car from the local train store last year. It is from the Lionel 2011 Volume 2 catalog & the catalog number is 6-27895. When I tried to loosen the original Lionel trucks to remove the 3-rail axles, the springs in the side frame of the sprung trucks flew out & I couldn’t find it after an extensive search. So I threw away the damaged & undamaged 3-rail trucks. A few weeks after when I tried to resume the project I realized that unknowingly I also threw away the original screws that secured the trucks to the bottom of the car. I took the car to the local Ace Hardware but I couldn’t figure out the screw size for the threaded hole.
I resumed the conversion after 8 months. I used Kadee 805 couplers & Atlas-O 2-rail Andrews trucks (Item #: 7033). I used the older style trucks with relatively wider side frames since they were cheaper than the latest Atlas-O 2-rail trucks with narrower side frames.
Adding Kadee Couplers
I used shims / spacers to lower the bottom of the wooden deck floor to the same height as the lower sills. I used 2 spacers at each end. I lightly sanded the bottom side of the wooden decks & used Loctite Super Glue sparingly to position / center the shims at a location that was approximately along the longitudinal center-line of the car. I was going to secure the couplers using screws & I deliberately used as little glue as I could get away with. Since the lip on the coupler top plate would rest outside the sill, the final position of the 2 holes on the coupler would not align with the holes on the shims as shown in the 2nd photo. These Spacers were O-Scale Laser Cut Coupler Shims that were 0.025” thick. They fit the outline of the Kadee couplers perfectly & they are available at Micro-Mark in sheets of 60. http://www.micromark.com/o-sca...-pkg-of-60,9822.html
The space between bottom crossmembers / braces on which the deck rests, is not of the same width at each end. So I used a paper-trimmer to cut the shims to the needed width. After positioning the top plate of the Kadee coupler over the shims & marking the location using an extra fine-tip metallic paint pen, I secured the car in the light-duty Dremel drill press. I propped up the free end of the car & using a Level, I was able to ensure that I was drilling a vertical hole. I used a #51 (wire gauge) drill-bit to drill the threaded hole for the 2-56 screw. I wore my old drill-bit trying to drill through the die-cast metal. I had to order TiN coated short length drill bit midway through drilling to complete the holes. I used 108 light multi-purpose oil sparingly to lubricate the drill & tap.
I used a 2-56 inch-thread bottom tap to tap these holes. In this conversion I drilled through the vertical bulkheads at the end since I was not planning on removing them later. I might have paid closer attention to the drill & tap depth if the ends did not have bulkheads.
I did not use any more shims when I attached the Kadee couplers since I was trying to lower the car to the prototypical deck height. I used 2-56 screws that were ½” long at each side to secure the couplers to the car.
Adding Atlas trucks
I enlarged the existing threaded hole (approximate inner diameter: 1.86) to remove the screw threads using a 2.5 mm short length drill, with my Dremel drill press. I used a level to ensure that the holes were drilled vertically. I decided to re-tap the threaded hole at the bottom of the car using a metric M3 X 0.5 thread, Ti-N coated bottom tap. I had to advance the drill & tap very carefully using the 108 oil sparingly, since the metal cross-members that had the holes is directly below the wooden deck & they were through / open holes. The drill might have gone through the deck if I wasn’t careful.
I chose tight tolerance shoulder screws since the Atlas trucks have a recess at the bottom of the truck & I wanted to use the 6 mm diameter head on the screw, as the pivot inside the 6.15 mm diameter hole in the truck to minimize wobble. I measured the Atlas truck & the depth of the original threaded hole to decide the shoulder length & screw length. The screw had a thread-lock patch but after repeated assembly & disassembly to get to the prototypical deck height, the thread-lock patch started wearing off.
I used a single ultra-low friction oversize Teflon washer (0.5” Outer Dia, 0.18” Inner Dia, 0.04” thick) between each truck & the car & similar Teflon washers between the screw head & the truck. I experimented with this washer stack using 2 washer thickness (one with 0.05” thickness & the other with 0.015” thickness) to balance my need to allow the trucks to pivot freely while minimizing wobble & preventing the pivoting trucks from loosening the screw as it is mounted from the bottom. Since these washers had an outer diameter of 0.28”, to make them fit inside a 6.15 mm diameter hole, I had to snip a ~3 mm long sector of the washers to make it fit inside the hole.
As a final measure against the screw loosening & falling out, I used Loctite, medium strength “Threadlocker 220” on the screw threads after I achieved the prototype deck height. I had to get this specific formula online. The Loctite threadlocker available in hardware stores around town was the 240 series that is typically used for screws larger than ¼” diameter. Having used this 240 series formula at work on test engines in the lab, I knew that the liquid is more viscous & does not get well into the thread in smaller screws or in screws with finer thread pitch. The medium strength, according to Loctite still allows the screw to be removed if needed, without excessive effort.
I learnt online that the prototypical deck height for these Pullman Standard cars is 44” from the rail-head to the top of the deck. I was able to achieve the 0.92” height for this car after the conversion. I initially had concerns that the low height would severely limit the ability of the trucks to pivot. But since this was originally a 3-rail model, Lionel has molded grooves at the bottom of the car for the 3-rail wheel flanges to stay clear of the insides of the car on O-36 curves. The coupler box & not the car sides limit the range of motion but the car moves without any issues on an Atlas-O #5 turnout on my diorama. I do not have a layout & so I wasn’t able to test my design on curved track.
