@WBC posted:"Bogie" is the proper term.
https://en.wikipedia.org/wiki/Bogie
https://www.tasrail.com.au/glossary-of-train-speak
http://www.railway-technical.com/glossary/
But yes, the bogie is commonly referred to as a 'truck' in AAR terminology.
No, it is not. This is not the UK or Tasmania. They don't decide. This is North America. We don't write "organisation", either. Heck, even my spell check knows that "organisation" (and its brethren) is wrong.