How to weight HO scale rolling stock, install metal wheels and set coupler heights

In this quick little video, I show you how I weight rolling stock (according to the NMRA standards) how I check coupler heights and install metal wheel sets.
Sometimes when you buy used rolling stock, it's hard to tell if you have metal or plastic wheels, so at the end of the video, I show you a quick little test I use that will answer your question 100% of the time, and removes all guess work.