USAT floppy axle issues/fixes

Some people have tremendous problems with the swiveling outer axles, picking points is the most common complaint. Others have absolutely no problems.

First, ensure that the spring/suspension mechanism in the chassis is lubricated. When operating properly, this motor block tracks excellently, acting like a 2 axle motor block with a pilot truck.

But first, you should understand a bit more how this all works.

In the picture below you can see how the "lead axle" can pivot side to side. What might not be immediately obvious is how this can also pivot up and down.

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Notice in the picture below there is a U shaped plate just above the lead axle, this is a bearing plate and a guide.

Recently I think I found the reason for the complaint: The swiveling axle has a pin in the top of it's separate motor block. This pin slides in a curved groove in a chromed metal plate to guide it.

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The picture below shows the plate with the pin from the floppy axle gearbox, and with springs and washers. The springs are the vertical suspension system, and the pin rides in the curved slot.


I noticed mine were very hard to move. The metal plate was not real smooth. So, unlubricated, even with the loco on it's back, it was still really hard to slide side to side. So, your loco goes into a curve and the axle does not move to follow the curve.

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I put some moly grease on the plate and worked it back and forth, it made a huge difference in the ease of swiveling. If this does not give effortless movement side to side, you might have to remove the guide plate and polish it smooth.

Check this out on EVERY 3 axle USAT loco before you swear at these trucks.

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