Update - if you locate the file 'farms.xml' located in your savegame folder: (default) This PC>Documents>My Games> FarmingSimulator2019> Check the specific Savegame# folder you are using. Stop server. Edit 'farms.xml' and look under each farm in there for the following, delete any grant access code ...

Can confirm this on PC as well. Have replicated. Have also had other players as farm-manager roles remove contractor access, and upon relog, contractor access is restored.

If you are in multiplayer, the option is fully removed from the menu - you can't TAB into the engine and take control. However, if you stand next to the tracks, and wait for the train to come past (I've noticed in both maps the trains run counter-clockwise) that you can press "E" to enter ...

For multiplayer on PC - if you're joining someone else's server, then you have what you need by having the game. You will obviously need to get the same mods (if any) that are running on the server to join, and if a secured server, then a password from the server owner/moderators. For voice chat, th...