I only know so much...but often the tags are an artist's or a consortium of artist's mark/name. They often work in groups and that is why there are sometimes smaller tags - sort of like credits for who contributed. In this example there are a number of people credited in the small text on the left. The tagging often happens while the trains are parked for a while. Grain cars like this one will get tagged while parked in Saskatchewan or in the rail yards of Vancouver.

source

#kamloops #train #graffiti #art

https://mstdn.party/@thegraffitiexpress@mstdn.social/111768694852632595

https://universeodon.com/@thegraffitiexpress@mstdn.social/111608939574332497