How to replace Micro Train trucks (n scale)

I guess this goes to show you should never assume someone has enough experience you can leave things unsaid!
Yes... The bolster pins (in the middle of the truck) just press into place IN MOST CARS. Bachmann cars use screws, and ConCor(?) and sometimes Kato use a split pin that is best removed from the inside of the car if you don't want to break it. Of course, MT trucks and couplers won't be original equipment on these...
The easiest way I've found to remove the pins is to hold the car upside down and slide a pair of curved tweezers under the bar connecting the sideframes, then pry it up. It should come off with little trouble.
Now - to remove the coupler pin, put the truck upside down on a hard surface, and use those same tweezers to press down on the coupler on either side of the pin. Pull the pin out with a pair of needle nose pliers. Be sure to grasp the _straight_ part of the pin, and pull _straight_ up. Replace the coupler by pressing the bolster pin back into the body, and you're done.