Mains must be lined and locked back for main line movement period.
As a courtesy and by protocol, we do talk to each other a lot.
Example...I switch on our major lead...the round house lead and rip track leads both intersect it...
I "own" that lead, and every track that comes off of it...if you want to come out of the "house", you have to ask for and receive my permission...and as a courtesy, you line behind if you can.
If you don’t, you tell me that you left a switch bad...when I acknowledge that fact, the switch becomes my responsibility...if we run through it, my bad, not the crew that left it that way.
But if you "sneak" out of the house, don’t say a word to me, and my engineer come scooting around the curve and gets the switch, you can bet that the crew who failed to line behind, or inform me of that fact will be "downtown" right along we me and my crew.
Most yards develop their own protocols, but GCOR 6.27, and that railroads own safety rules govern...along with the SOFA groups recommendations.
Yardmasters ride herd on the yard crews, and do have to play traffic cop all the time, but most yard crews have worked the same yard and same job for a while, so everybody "knows" the other crews style of working, we all cover each other fannys...the whole idea is to not get in each others way.
Now, the rules in the GCOR and my railroad direct me as to what switches I have to line back...main line switches, house track and rip track switches, crossovers must be lined for the tangent route when not being used...unless they are "manned" during switching operations...but bowl track switches pretty much stay how the last guy who switched there left them.
Ed