Just seen this come up in my recommended on Youtube, it may be, according to the comments, the competition DTG of all people need.
It looks to offer a variety of roles within the simulator, dispatcher as well as multiplayer. Not sure on SDK, but it’s not Unreal Engine. So an editor may be possible.
Side note, TML have been banging on about The Bus having an editor but from experience, UE4 isn’t very third party friendly, lack of community involvement...