Operating crews are required to have proficient knowledge of the territory they operate over. They must commit to memory every characteristic of that territory including locations of grade crossings, signals, interlockings, sidings, mileposts, speed limits, as well as who controls that territory and how to contact that person. If that territory is controlled by another railroad, the employee operating over that territory must be familiar with the set of rules the controlling railroad operates by. It's not as simple as pushing a lever and the choo choo moves, it's a very intricate operation.
Why hasn't it been decided yet? When multiple entities are involved in anything there's often a negotiation period, and sometimes that takes longer than expected.
Moderator: Massachusetts Bay Transportation Authority, Brightline Trains
Avatar:3679A (since wrecked)/3623B (now in service as 3636B).