Shortening the drawbars on both my Athearn Challengers and Big Boys is one of the first things I do with them.
Photo (1) - Comparison between stock Challenger and Challenger with shortened drawbar:
I remove the drawbar by using a methodology similar (if not identical) to the instructions on the thread
@NDave has included in his post. However, I drill another hole in the drawbar of equal diameter to the hole already in the part and cut the extra length off. No gluing, truing or worries if the glue's gonna hold. Then I put the drawbar with the new hole back on the model.
The only caution is to make sure the new hole is centered as there's not much "meat" on either side of it.
As for where to drill the new hole, I don't remember exactly where I did it since it's been several years since I've done it. I have several Challengers and Big Boys I haven't done it to yet, but my Challengers are shortened about right, whereas I got my Big Boys a bit too close...even though they still work on my layout with its 24" minimum radius.
What I will do on future shortenings is take a measurement of how much too long the stock drawbars are on those Challengers and Big Boys I'm gonna work on, then mark the new location with my digital calipers, punch a dimple in the center of the drawbar as a starter dimple for the correct drill bit size, and drill the new hole, and snip off the excess from the modified drawbar.
As you can see from the photos, the horizontal plate between the back of the cab and the front of the tender should overlap the tender's front platform...but not too much. On an unmodified Big Boy, measure from the back of that plate to the point you think it should be on the tender, then drill your new mounting hole measured from the center of the old mounting hole to the center of the drawbar (side to side) which will get you the length you think is correct.
I should probably look at my references to see what the actual distance between Big Boy and Challenger tenders and the back of their cabs is, but oh well...not tonight!
When reassembling, make sure the speaker wire doesn't get pinched by the front mounting peg inside the tender when you screw it back together.
Photo (2) - Challenger with shortened drawbar:
Photo (3) - Big Boy with shortened drawbar:
I think this modification really adds a subtle, but significantly more prototypical look to these models...something that visitors may not be able to put their finger on, but which make modified Big Boys and Challengers look a lot more "real".
Cheerio!
Bob Gilmore
