Over the past few months I've purchased some used, mostly Athearn, HO boxcars. I've disassembled, cleaned and tweaked them, installed metal knuckle couplers (KD and/or ProtoMax), and then test run them. While doing so I kept seeing a small container in a box I have that has about 50+ brown plastic couplers in it that I had removed over time from newly-acquired, used, freight cars, and thought, "Maybe there is a way to make these useless-for-me-couplers functional on long trains."
In my experience the major problem with plastic knuckle couplers is that their necks can and do (under stress) bend vertically (up or down) when pulling long trains, and thereby often create train break-in-twos caused by their knuckles separating from each other (i.e. vertically sliding apart.) That's very irritating - to put it nicely.
So I came up with an idea on how to use those plastic couplers, did some testing, and it has worked well - so far. The key (believe it or not) is Athearn's couplers' metal floor plates - the ones that snap on and have been around for four? decades. If you're interested please read on.
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Take the metal floor plate - with its two snap-on "ears" and its "tongue" that sticks out a little less than 1/8" - and do the following:
1. On the floor-plate with its ears up, take a small file and smooth the floor plate (between the ears) all the way over past the tongue (only takes about 4 or 5 swipes.)
2. Then use a small file on the end of the tongue at a roughly 25 degree angle (this is so the coupler neck will slide on it smoothly).
3. Now here's the key: take a smallish pair of pliers and bend the tongue UP about 25 degrees from level.
4. Put a plastic coupler in the large part of the coupler box.
5. Snap the metal coupler plate onto the larger part of the coupler (which is probably already on your railcar.)
6. Test if the plastic coupler is able to slide side-to-side. If not , make a minor adjustment or two. And, try to not leave any significant vertical space above or below the sliding coupler neck.
7. Couple some of the above-mentioned tweaked railcars (I used 5 boxcars) in a string and see if the knuckles meet each other at the same height as a height gauge. (If not I use a shim where needed.)
That’s It! Now for my operational tests on flat track and the results:
Test #1: I put the 5 test boxcars right behind two engines and in front of 58 other railcars. I ran this train around an L-shaped loop, 22" radius, 3 times. And then I backed the train around 3 times. No problems at all, and all ten of the plastic knuckles were still evenly coupled to each other.
Test #2: I put the 5 test boxcars right behind the same two engines and in front of 63 other railcars. I ran this train around an L-shaped loop, 16" radius (that's not a typo), 3 times. This time there was a train break-in-two of the plastic couplers . I removed what looked to me like the weak plastic coupler, installed a new one, and then resumed running. No more problems. And then I backed the train around 3 times (not real slow, but not speeding either.) No problems at all, and all the plastic knuckles coupled to each other evenly.
Hope this was at least interesting and maybe helpful to you. If you say I'm crazy, I won't dispute it!
DougC
P.S. For me I know it's easier, less trouble, and more reliable to just install KD and similar metal couplers vs. messing with these plastic couplers. But it's kind of neat to know that it IS possible to use those rascally plastic ones on long/heavy trains (and maybe save a little money too).
In my experience the major problem with plastic knuckle couplers is that their necks can and do (under stress) bend vertically (up or down) when pulling long trains, and thereby often create train break-in-twos caused by their knuckles separating from each other (i.e. vertically sliding apart.) That's very irritating - to put it nicely.
So I came up with an idea on how to use those plastic couplers, did some testing, and it has worked well - so far. The key (believe it or not) is Athearn's couplers' metal floor plates - the ones that snap on and have been around for four? decades. If you're interested please read on.
-------------------------------------------------------------------------------------------------------------------------------
Take the metal floor plate - with its two snap-on "ears" and its "tongue" that sticks out a little less than 1/8" - and do the following:
1. On the floor-plate with its ears up, take a small file and smooth the floor plate (between the ears) all the way over past the tongue (only takes about 4 or 5 swipes.)
2. Then use a small file on the end of the tongue at a roughly 25 degree angle (this is so the coupler neck will slide on it smoothly).
3. Now here's the key: take a smallish pair of pliers and bend the tongue UP about 25 degrees from level.
4. Put a plastic coupler in the large part of the coupler box.
5. Snap the metal coupler plate onto the larger part of the coupler (which is probably already on your railcar.)
6. Test if the plastic coupler is able to slide side-to-side. If not , make a minor adjustment or two. And, try to not leave any significant vertical space above or below the sliding coupler neck.
7. Couple some of the above-mentioned tweaked railcars (I used 5 boxcars) in a string and see if the knuckles meet each other at the same height as a height gauge. (If not I use a shim where needed.)
That’s It! Now for my operational tests on flat track and the results:
Test #1: I put the 5 test boxcars right behind two engines and in front of 58 other railcars. I ran this train around an L-shaped loop, 22" radius, 3 times. And then I backed the train around 3 times. No problems at all, and all ten of the plastic knuckles were still evenly coupled to each other.
Test #2: I put the 5 test boxcars right behind the same two engines and in front of 63 other railcars. I ran this train around an L-shaped loop, 16" radius (that's not a typo), 3 times. This time there was a train break-in-two of the plastic couplers . I removed what looked to me like the weak plastic coupler, installed a new one, and then resumed running. No more problems. And then I backed the train around 3 times (not real slow, but not speeding either.) No problems at all, and all the plastic knuckles coupled to each other evenly.
Hope this was at least interesting and maybe helpful to you. If you say I'm crazy, I won't dispute it!
DougC
P.S. For me I know it's easier, less trouble, and more reliable to just install KD and similar metal couplers vs. messing with these plastic couplers. But it's kind of neat to know that it IS possible to use those rascally plastic ones on long/heavy trains (and maybe save a little money too).
