Why would you remove the center axles on older Athearn diesel?

[Geno]

I recently purchased an earlier blue box  Athearn PA diesel off ebay.  It has a total of 6 driven axles and  middle axle in each truck was removed and enclosed in the box. This was in the description.  Does anyone know why the center axle on each truck might have been removed?  The locomotive seems to run and pull fine and does 18" and 22" radius curves fine. I just wondered if there was a problem with these locos.

[jward]

other than their long wheelbase making them derailment prone on less than perfect track, i am not aware of problems with this locomotive. and removing the center axle won't do anything to help this as the wheelbase remains the same.....

i'd see if i could get a pair of wheelsets and fix the problem.

[RAM]

If you put the center axle in, you will find that it will not run on the 18"  or 22" radius curves.   

[ACY]

I know that an Athearn PA with the center axle installed will not run on 18" radius track. I have a few they will run fine on 24" radius with it installed however.

[Doneldon]

Geno-

I think it's mainly about making it around tighter
curves but there should also be a little more
pulling power since all of the loco's weight is
now on powered wheels.
                                             -- D

[Woody Elmore]

There used to be an issue with the casting warping. I remember a friend who had a PA and the trucks rocked on the center axle.  ALso the three axle trucks were prone to derailment.

[mabloodhound]

It's just as simple as what everyone here has said.   It won't make it around the 18" and 22" radius curves.
However, if you machined (filed) the flanges off the wheels, it would then be able to work and hence the flanges wouldn't restrict the wheelset side movement on sharp curves.

[Terry Toenges]

Probably be easier to find flangeless wheels of the same size.

[jward]

interesting.......

i have an athearn pa that i use for track testing. once i have used it to fine tune the track i have had no further derailment problems with it. and most of my curves are 18' radius. my pa is the older version with the metal sideframes, perhaps the newer ones with the plastic sideframes are pickier on track?

[Geno]

I actually have a pair of these PA's, both with metal trucks, older production, one with the removed axles and the other stock with all six axles.  I have an 18" radius inner track and a 22" outer track and both locomotives run either track without any problems.  I guess like some of the bigger Bachmann locos, the radius the loco can run  varies in the same model.

[r0bert]

It's not the radius of the curves that cause the PA problems, at least not the radius size of the track, that is...
The PA's problem envolves the vertical curves, (the dips and humps of the railhead on either one or both of the rails) because the PA truck does not allow for much vertical movement of the axles.
The truck can teeter-totter over humps, and if the track is uneven enough, the axle at one end is lifted far enough over the rail for the flange to clear, sometimes it comes back down in line, and some times it doesn't.
Removing the center axle, (the fulcrum of the teeter-totter) acts as a
band-ade, allowing  them to operate over ruff trackwork.
I too, use the PA as a benchmark gauge when laying new track, with it moving slowly, anyplace I can see the end wheels lifting, I will shim and level the rail, both rails, if needed, until the PA operates flawlessly, and when all is well with th PA, anything will perform well. 
This seems to not be an Athearn only, but a PA issue,  Proto, and the Kato N scale PA can have the same problem.

[Stephen D. Richards]

Geeez fellows!  Now I hav to go buy a PA so I can have a "fine tuning track tool".  Oh wait, I can never buy just one!  lol  On the other hand...great ideas and outstanding advice.  Always need a good reason (excuse) to buy more locos!  I will try this technique.  thanks,  Stephen

[jward]

you will never find a sleeker, more beautiful track tester.....

[Stephen D. Richards]

To all, now I've gone and dun it!  I have an Athearn PA1 coming to me and I'll let you know what I think of this brand new track tester!  At least for me it is.   Stephen