Since Krispy calls upon me once again to clarify an issue, I will try to oblige.
I didn’t work too much in the Hicksville area but when I did, in 1963, Atlantic Pipe track was used mostly for building up our westbound train.
You mention the Mail Dock in the Advance Yard.
I owned a job, in 1960, that went to work at 11:30 PM at the Mail Dock.
Three cars were spotted there,
Two MUBM or RPOs for loading and a PBMU sleeper/rider/horse.
About 1:30am, we were rudely awakened with a loud kick on the side of the PB and we ran the cars into the station to add onto the head end of trains headed east.
Cars were then picked up from Johnson Ave Yard and taken back to the Mail Dock to be loaded.
The previous scene was repeated about four am.
The tricky part came when our single rider was sent through 5 Station to return to the Mail Dock.
Running uphill with a single MU car required cutting out the speed control and hanging halfway back in the station before getting the signal to run over the ten car gap.
This single car was added, I believe, to a Hempstead train about six-thirty.
During the night, a passenger crew was busy gathering up MU mail cars from various terminals around the railroad and arrived in Jamaica about five-thirty.
Cars for Jamaica were switched out and cars carrying westbound mail were added and the crew was sent on their way to Sunnyside Yard where they were sorted at the Post Office there.
Hope this is of interest.
JJ Earl