Derail Problem with a PK 1 Erie Bulit

[cudaken]

 OK, more than likely the track because it happen's pretty much at the same spot but! I have two of them A and B booth powered. One will make the board with no problem the other one between 1 to 2 and derails in the same spot.

 I have checked the wheel gauge and with in specks. But unlike PK 2000's I have there are no brass bushings that help hold then to the truck frame. I all so found the center drive wheels (has 6 of them per truck) have a lot of slop from side to side. I have yet to check the one that runs well for slop.

 I need a second puller so I did a cheap trick. I pulled the center drive wheel from the B enginge and derailing stopped. But down side is the center drive wheel power the out ward power wheels so it is only 4 wheel drive. Still added the little extra I needed to pull the load but, well you know.

 Any ideas?

                 Ken

 

[river_eagle]

you're right in guessing that the track is the problem.
the derails are caused by vertical curves (humps/ dips) in the track.
as your locos go over the hump the long 3 axle trucks are floating high enough on the center axle for the wheelflanges on the end axles to clear the rail, and settle back outside the rail or even on top of it.
you may not notice the wheel is off until you hit a curve or other track feature to kick the truck way over.

run the loco with all wheels in place VERY slowly around the layout watching the wheels and truck motion to find the exact track location lifting the wheels off the rail, and repair that area.

the loco works with the center axle removed because you are removing the pivot point giong over the hump.
if you can't remove the hump completly, you may be able to shim the track on either side to lessen the severity of the hump.

[selector]

I agree, Big Guy.  Get a straight-edge that you can lay on the rail-tops along the axis of travel.  Put a flashlight behind the straight-edge and get your cheek-bone right down on the layout so that one eye can see where the railhead meets the straight-edge and the flashlight can shine through any gaps.  You will undoubtedly find your rising kink, most probably at a join.  It would be no problem on a straight, but you add the curve, and what river_eagle described happens.

One more thing...are the trucks smooth in their rotation around their central pivot?  Is there an obstruction that they bind on when they try to go in one direction and far enough to make contact?

[cudaken]

 I know about the center wheel being a piviot point and cause the front wheel to lift. That is why I pulled it. But the part I don't understand is why one Erie Bulit will run the board great and the other one derails? Same chassic, same trucks and wheels. That is why I was asking about the movement side to side in the B-unit. All so the reason I asked this question. Could the wheel flage depth be driffrent and cause this? When I frist laied the new rails the E-6's all hated it but Eries where OK with it. Reason is the Eries have a shorter truck so lift was not as much. Now the E-6's and BB 12 wheels are PK with it and the lone Erie hates it.

 Besides my lack of track laying skill, is there any other ideas?

 

            Cuda Ken

 

 

[Leon Silverman]

I made this suggestion before but I think it bears repeating:

    When I built my last layout, I used a circular bubble level  to check for smoothe trackwork.  This is a level about the size of a thick wristwatch that has a bubble instead of a watch face on the top.  It is marked with a small circle in the center of the level which will identify when the level is oriented flat in all directions.  Place the level on top of your track work and slide it along the rails at a slow, steady pace.  Any kink, dip, or rise in the track work will immediately reveal itself by causing a shift in the position of the bubble relative to the center circle as the level traverses the irregularity..

Another possibility:  I believe the center axle of the C-liner is unpowered and thus unconnected to the gear train.  Would it be possible to deepen the axle recess to allow it float up and down rather than lift the truck.  The Penn Line GG1 powers only the middle and outboard axle in each truck.  The inboard  axle on each truck  is allowed to float in the truck in order to provide room for the worm gear coupling.  In doing so, the powered wheels maintain constant contact with the rails. 

[TwinZephyr]

There really has not been enough information provided for anyone to accurately diagnose the root cause.  Derailments could be caused by uneven track, track or wheels out of gauge, attempting to run trains on curves or turnouts that are too tight, mixing cars with truck mounted and body mounted couplers in the same train and a whole bunch of other things.  Perhaps a careful reading of a Kalmbach tracklaying book or a Model Railroader article on tuning up rolling stock or reducing derailments would prove helpful.