Some great mods for better trains in GTA V, including passenger trains. Unfortunately no longer updated. These mods are required, and instructions must be followed carefully:

https://www.gta5mods.com/maps/2trai...
https://www.gta5mods.com/vehicles/ov...
https://www.gta5mods.com/scripts/rai...
https://www.gta5mods.com/scripts/men...
https://www.gta5mods.com/scripts/map...
https://www.gta5mods.com/misc/gta5...
https://www.gta5mods.com/tools/heap...
https://www.gta5mods.com/tools/packf...
https://www.gta5mods.com/tools/scrip...

as well as OpenIV