AHM/Rivarossi Obsevation Car coupler upgrade


flyboy2610

Loveably weird
A couple of weeks ago, I purchased a Rivarossi observation car in UP greyhound scheme. I've been collecting cars in this color scheme for a passenger train. I like the look of these cars a lot better than the normal UP Armour yellow and gray scheme. I have a UP 4-8-4, #806, that I installed a Soundtraxx Tsunami sound decoder in. It will look smart at the head of this train!
I bought this car to finish off the tail of the train. I'd been looking for a greyhound scheme observation car, and when I saw this I snapped it up. The windows are dirty and don't want to come clean. Sometime in its lifetime someone touched the windows with smudgy fingers and now I can't get them clean. I'll keep trying, though! On these cars, the roof and windows are glued together at the factory. There are 6 tabs (two of which are broken on this car) which snap into slots in the floor to hold the roof/windows on.
The car came with truck mounted horn hook couplers. Truck mounted couplers on a long car like this don't bother me to much. This will be the last car of the train, and I do not have to back into the passenger station. The other 5 cars in the train are Walthers Heavyweight cars with body mounted couplers. The curves on the mainline are all 24" radius or greater.
This car was also a real lightweight, and I'm talking literally here! It is 11-1/4" long, so according to NMRA recommendations it should weigh 6.6 ounces. It weighed 4. I used 1-1/2 ounces of weight over each truck to bring it up to 7 ounces. A bit over, but there are no grades on my layout, so it should be fine. It also had 33" wheels instead of the 36" wheels you would normally expect to find on a heavyweight passenger car. More on this later. I removed the stock wheels, and will be replacing them with Proto 2000 36" metal wheels. A test fit reveals that they roll very smoothly in the trucks.
Here's a pic of the car in it's state of disassembly:
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I checked Kadee's website, and the conversion requires a #505 bolster for each truck. Last Saturday I placed an order with M.B. Klein's. It shipped Tuesday morning, I had the package Thursday evening. These are the bolsters required:
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This is what comes in the package: two each bolsters, #5 couplers and centering springs, two short self tapping screws, two long self tapping screws, and a few extra knuckle springs. You also get instructions, but we never look at those do we? In this case, you'd better! :D
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In the previous pic, I have one bolster facing up and one facing down so you can see the details. The bolster is slotted to permit back and forth adjustment of the coupler. You can see the slot in the top bolster. On the bottom bolster, you will see a series of raised lines on the sides and ends of the slot. Whether or not you keep those depends on which car you have. The early AHM cars came with 33" wheels. Mine had 33" wheels, so I have an early car. The later cars came with the correct 36" wheels.
The original 33" plastic wheels is on the left, the replacement Proto 2000 36" wheel is on the right.
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The spacer lines on the bolster are there to set the proper coupler height. If the 33" wheels are replaced with 36" wheels, the coupler will then sit too high. The spacers lines lower the coupler back down to the proper height. If the original 33" wheels are retained, the spacer lines must be filed off or the coupler will sit too low.
So: If you have a later car with 36" wheels from the factory, the truck has been manufactured to place the coupler at the proper height. Leaving the spacers on will result in the coupler being to low. The spacers must be removed.
If you have an early car with 33" wheels, the truck has been manufactured to place the coupler at the proper height. Leaving the spacers on will result in the coupler being to low. The spacers must be removed only if the 33" wheels are retained!
The only time the spacers must be retained is if you have an early car with 33" wheels and you replaced them with 36" wheels. Removing the spacers will result in the coupler being too high. I have an early car with 33" wheels, and they will be replaced with 36" wheels, therefore I need to retain the spacers. That should save a lot of filing, right? Guess again!

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The pin that the old horn hook coupler clipped onto must be cut off and filed down smooth with the top of the plate.
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The bar across the front has two sides with small L-shaped ledges that must also be removed. These have to be removed so the bolster can slide into the pocket.
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The instructions say to remove the center bar if using the spacers on the bolster. Otherwise the bolster will be too thick to slide into the pocket. They also say do not remove the bar unless absolutely necessary because doing so will weaken the pocket and eliminate a potential mounting point for the bolster. I chose to leave the bar in place, but file it down thin enough to still be able to slide the bolster into the pocket. It's not laser level flat, but it will do:
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A couple pics of how the bolster slides into the pocket.
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The instructions say to assemble the coupler onto the bolster before fitting the bolster onto the truck. I chose to leave the coupler off until I was done fitting the bolster. I felt there was less chance of damaging the coupler that way. I'll continue this in my next post. I can't post any more pics to this one.
 
OK, part two.
The instructions say to use a #56 (.0465) drill bit to burnish the shank of the #5 coupler by rubbing it back and forth over the shank. I'm guessing this is to knock down any micro-burrs that may be present. Once that is done set the bit aside, but don't put it away because you're not done with it yet.
I placed the cover down on the workbench and installed the centering spring. The spring must always go on top of the coupler. The coupler will be assembled upside down, so go ahead and install the spring into the cover. Lay the coupler onto the spring, trip pin pointing up. Give it a puff of powdered graphite. I'm sure most of y'all know this already, but: NEVER use any type of oil or grease in your couplers! The oil will congeal and the grease will get hard, and someday when you pulling a long train up a steep grade the coupler will let go, and you will have a pile of smashed up cars at the bottom of the grade. Use only a dry powdered lubricant that is safe for plastic.
Next I positioned the bolster tongue over the coupler cover and using the SHORT self tapping screw screwed them together. Get them nice and tight, but don't over tighten the screw or you will strip it out.
The assembled bolster:
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Now the position of the bolster in the pocket must be established. The instructions say to position the bolster so that the trip pin of the coupler is inline vertically with the end of the car. Looks pretty good right there, I'd say.
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Now, without moving the bolster, I made a mark roughly centered in the middle of the slot. This is where I will drill a #56 hole for the long self tapping screw. (I told you not to put that drill bit away!)
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And this is when Homey did something stupid.
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I put the #56 drill bit in my pin vise and started trying to drill the hole. Apparently I didn't make my center punch mark good enough because the drill bit just wanted to slide across the plate. So I took my center punch, lined it up on the hole, gave a good push, and......... I cracked the plate! :eek: :mad:
You may have to look hard, but there is a crack running from the right hand side of the screw hole to the edge of the plate. To quote Queen Victoria: "We are not amused."
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My first thought was to dill it out larger for a 2-56 screw and use a nut on top of the plate to secure the bolster. But the slot in the bolster is not wide enough for a 2-56 screw head. The nuts are .062" thick, so I decided instead to use a piece of .060" styrene glued to the top of the plate. These truck seem to be made of styrene, they do not feel like acetal plastic at all. So I cut a piece of styrene and glued it to the top of the plate.
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I also broke off a brake shoe bracket last night. I glued it back on with Testors model cement. It seems to be holding up just fine. I will need to bend it slightly when I put the wheel on.
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On to part 3!
 
Part 3.
After the plastic model cement had done its work, I finished drilling the hole for the self tapping screw. I know, drilling a hole for a self tapping screw does seem like something of a dichotomy, doesn't it?
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I slid the bolster into the pocket and installed the long self tapping screw.
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I then installed the front and rear wheels into the truck and checked the coupler height. Hmmm....... seems a bit high. But you can see here why the spacers had to be left on. If I had removed them, the bolster would be sitting even higher in the pocket, and the coupler would be ridiculously high!
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I don't seem to have any medium overset standard couplers on hand, and I only had one long overset standard coupler. I installed it into the coupler pocket, and the height is much better!
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I next put one of my Walthers heavyweight cars on the test track and checked the height. Looks pretty good. I never realized, though, how far back the couplers on the Walthers cars are!
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I'll stop by my local train store tomorrow after work and see if Randy has any Kadee #22's in stock. If not, he'll order some for me.
I do have some short overset standard couplers. Between the medium and short couplers, plus the fore and aft adjustment of the bolster, I'll have this car doing the back end of my passenger train proud!
I'll have to mix up some paint to see if I can come close to the color of the trucks. I am not going to leave that styrene white!
All in all, this project went pretty well. It took a lot longer to write it all up than it did to install the bolsters!
 
Excellent, detailed instruction. I have done a number of these conversions myself. Not sure what you can do about the windows, however. I placed material behind the glazing to simulate shades pulled down to various heights. In a few instances, I used a permanent black marker to look like the shadows cast by passengers. Otherwise, you may just have to live with the fogging. Great job!
 
Thank you, trailrider! I appreciate your kind words.
Your idea about the shades is interesting. I may have to look into that. Periodically I polish the headlights on my van to remove oxidation from the plastic lenses. I use toothpaste (I forget what brand), and it works really well for that. I though of doing the same here, but I'm afraid it would scratch up the windows even worse. I may try it on a piece of scrap clear plastic just to see what it does. But otherwise, as you said, I may just have to live with it.
The long black piece of paper you can see in the first post of this thread is something I cut to cover the weights I put in the car. The sides of the window piece hold it in place.
 
Great job flyboy - if only I had the patience (and fingers) to do such things. I am even "scared" of changing out my plastic wheels for metal ones :rolleyes:
 
I love a good Rivarossi / AHM / IHC rebuld. Some of my favorites in the fleet have come from this process. Thanks for sharing this thread.

The early AHM cars came with 33" wheels. Mine had 33" wheels, so I have an early car. The later cars came with the correct 36" wheels. The original 33" plastic wheels is on the left, the replacement Proto 2000 36" wheel is on the right.
Look / measure again. The AHM RP-39 wheels are not 33" wheels. If I recall properly they are closer to 30" diameter (30.4" ?). The huge flange makes them look larger. That might explain part of the coupler height issue.

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...I then installed the front and rear wheels into the truck and checked the coupler height. Hmmm....... seems a bit high.
Also check that the molded on brake shoes aren't preventing the new axles from sitting properly in their sockets.

I don't know, it might just be the picture or camera angle, but your Kadee coupler height gauge might need to be re-calebrated from an NMRA gauge. Notice how the track and top of coupler gauge are parallel (green and red lines respectively), but the knuckle line (yellow) is not parallel with them. Looks like it might have been bent somehow along way (white arrow).
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Well, as Larry the Cable Guy might say "I done got 'er did!"
Randy, my LHS owner, didn't let me down! He had 2 packages of Kadee #22's. Now he's sold out. I added some styrene to the top of the rear truck, to give the self tapping screw some more material to bite into. I painted both styrene squares kind a greenish black. I think they look OK. With the Kadee couplers installed and new 36" wheels, here's how she sits: (although not at an angle)
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The car is very free rolling. Once I get the layout cleaned off, I'll assemble the train and take a pic for you. I know y'all just love pics! :)
 



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