I'm looking for a picture of the tender drawbar on the recently re-issued Athearn Big Boy. Apparently the drawbar was redesigned from the first run, and I'm told that at least some of them have a factory defect (a missing spring) that causes the tender to ride crooked relative to the rails. I'd like to add that information (along with a drawbar picture) to my website, but I don't have one myself. So... little help? Thanks! -Mark
Actually, if you have a first run Big Boy, a picture of that drawbar would be helpful as well (to demonstrate the differences between the two versions). Not being a UP steam guy, I sold mine off ages ago. Re-Thanks! -Mark
I talked with Chuck at Athearn about a year or so ago about the drawbars. He indicated to me that repairs involving replacement of the tender (remember MRC POS decoders melting the tender bodies?) were complicated by getting the "spring-thingy" in the old drawbars hooked up properly, and that Athearn was designing a new, simpler drawbar. Now, this was okay with me, since I chop the rear off the drawbars to get both Big Boy and Challenger tenders to be a prototypical distance from the back of the cabs, and the tenders run just fine with a hole and screw attaching them to the modified drawbar, instead of that complex "hole" and spring arrangement in the previous runs. However, I wouldn't recommend shortening the drawbars for anything less than an 18" minimum mainline radius. I haven't shortened the drawbar on my latest Big Boys, but I'll do that this afternoon and take some photos of the effort. I also have an unshortened drawbar in a first-run Challenger that need shortening too, and I'll photograph that for you before I chop the back of it off. Cheerio! Bob Gilmore
Apparently the redesign involved changing the locomotive end to a simple loop (ala what you did). The tender end is the original overly complex design - Here's a picture of the drawbar as it sits in the tender. The problem with this one (and apparently others) is that it's missing a spring - I'm having a hard time envisioning where exactly this missing spring is supposed to go and what it is that it does. Can anyone elaborate? Thanks, -Mark
I don't have one of these, but by looking at you're picture, I am guessing that there is a spring in both legs of the V shape? Would this be to let the tender gap widen when the loco goes around a curve? Then the gap would close up on straight track ? Think Bachmann tried something like this when they put out the HO Spectrum J. Never did work right IMO.....I would probably just design a simple straight drawbar myself. Interesting to see the outcome.....Mike
The guy who took those pictures says he thinks the spring hooks to that little notch in the "V" and then loops around the post behind it. Of course he won't be able to verify that theory until he gets the replacement spring that Athearn has promised to send him. -Mark
OK, I've updated the picture showing the spring installed. Pretty quick response from Athearn on this one, so kudos to them. Hopefully there aren't too many that have this problem. -Mark
The reason for the V is that, as the tender and loco 'round a curve, the tender actually shifts back on the inside of the curve, to prevent binding between the loco and tender. On a straight, the pin returns to the center and the tender returnes to its closer position to the cab of the loco. Fantastic design, and relatively mechanically simple. It allows quite a closer link between the loco and tender, the only other simple way would be an elastic or rubber connection allowing the outside-of-curve side of the tender to break away from the loco cab, but could cause slack under heavy drag. IMO, this guided connection-expansion mechanical link is a better design.
My challenger is also missing the centering spring on the tender end of the drawbar so the tender tracks crooked.
