I've got it to work. For anyone who wants it, here's what I've got:
(again, each '>' stands for 1 indention)
Ordered List - Set to repeat forever
>Set Signal Extended Rule - Set EB signal to Proceed
>Set Signal Extended Rule - Set WB signal to Proceed
>Check Trackside - Wait for any vehicle to enter crossing trigger
>>Set Signal Extended Rule - Set EB signal to Stop
>>Set Signal Extended Rule - Set WB signal to Stop
>>Check Trackside - Wait for any vehicle to leave crossing trigger
>>>Wait - 150 seconds plus/minus 0
Driver commands for each train going to the crossing
Navigate to trackmark > Crossing Wait Point (WB or EB depending on direction)
Wait until not red (Keeps the crossing from being activated in the 2.5 minute waiting period)
Wait for 1 minute (The crewman has to walk up to the electrical box at the crossing to turn it on. This simulates that walk)
ATLS trigger command (Actually turns on the crossing)
Wait for 1 minute (walking back to the engine)
-Some driving command here. The crossing clears automatically, so this is just the continuation of the train's schedule-
Now all I need to do is make a proper signal for it. For testing I used a simple red/green 2 aspect signal, and it looks concerning when a train stops dead at a green signal

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