I spent a few Saturdays at Hainesburg Jct in the late 50's.
As I recall it was an ALL day adventure. By 8 AM or so they would drop the tail of the Maybrook freight just west of the bridge in Portland and bring over the NYSW interchange and back it all into the old NYSW main to Gravel Place clear down to track end. Go back over, then head east. I believe they got to the west lead by BK just after noon.
They came west and picked up the NYSW set out in that small two/three track yard on the LNE just west of the Junction station. By then it was evening. Those FA's were a dreadful sight, nose to nose at times, mixed A's and B's, as darkness fell. Then they did a re-paint just before closing shop!!
I hope my recollections are of help.
Wish you well.
Joseph in VT