Improving the new u33's truck power pickup


Stuck on the Frogs!

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How can a loco with 12 wheels get stuck on insulated frogs? I assumed all 12 wheels were supposed to be able to pickup power from the track and therefore would easily bridge insulated frogs.  I only had this problem on ladder track turnouts on the layout. All track work was powered like it should be and it was clean and so were the locos wheels.   A close look at the problem reveals that: 1. The rubber traction tired wheel-sets do not pickup very well if at all due to the larger diameter of the rubber tires. 2. The middle wheel-set was not touching the track at all by design! 3. When the outer wheel-sets both were on the frogs it lost power due to.1. and 2.	This is the spot that the second generation AF u33  has trouble getting through.
This is the first generation u33 truck. It has a blind middle driver.  It does not have any pickup problem on the layout. There is no wheel suspension equalization on these trucks.	Here is the latest generation u33 truck. It is quite a bit different than the first generation. It has a flanged middle driver. The outer wheel-set has sprung journals.  The good part is the great new low speed gearing.
Here you can see the gap on the middle wheels. No traction or power pickup here!  Even though the outer wheel-set has sprung journals they do no allow the middle wheel to touch the track when the loco's weight is on them.	Here is the detail of the springs of the outer wheel-sets. DO NOT LOSE the springs! There is no part number for them yet so getting them may be difficult of you loose one.
This is the middle journal pocket before modification	Here is how I modified the journal pocket. I drilled holes for the new springs. The springs I used are  Kadee S gauge coupler pocket springs. They are 1/16" x 1/4" and are larger than the original Lionel springs but it is what I could find to use.  Note that I doubled the springs to get the tension I needed. I found springs at Lionel that work better than the Kadee springs. Lionel part number 6408036055.
Here is the truck bottom cover that need to be modified also.	A pocket need to be filed into the middle wheel-set position so the journal can match the travel of the outer wheel-set journals. The pocket is .020" deep
There are spacer sticker shims that need to be removed on the middle wheel-sets journals for maximum travel	When reinstalling the middle wheel-sets turn the journals so the non flanged portion of the journals is next to the bottom truck cover.
I also turned the rubber tires down a few thousandths on the lathe closer to the non tired diameter The middle wheels now are equalized and provide traction and electrical pickup after these modifications.

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