Im afraid of the "Bogie"-man

 I had never heard of a train bogie before.  

It is the wheel component of a train...

From google images and http://www.railway-technical.com/trains/rolling-stock-index-l/train-equipment/electric-traction-control-d.html

There are multiple examples of these in lego train sets:

So the bogies above are good illustrations in black of train bogies.  So, this is just meant to be an educational post "for dummies" like myself.  Also when typing bogies, make sure the keyboard doesn't automatically correct to bodies!!!

I bought some of these on pick a brick but there werent axles so the rep at lego sent me some which was kind...just know that you need axles for the wheels

I don't know how lego got all those into 1 bag...impressive packing

Easier to see the wheels against light background 

The box has the part number the axles came in!