The “mystery bridge” over Montauk Highway carried the electrified siding westbound from the eastbound #2 track, with the switch just west of the Banks Avenue overpass.
This track and yard were put in service in 1938 and extended to the original freight house, with additional sidings branching off to access the four (4) team tracks (all electrified). The "new" freight house track was added in 1950 to service the new freight house. This siding into the yard was elevated with the grade elimination of 1950, hence the “mystery bridge.”
The original freight house of 1938 later became the express house when the new freight house was built in 1950. I would think that prior to 1950, the old depot handled the express as was done in most instances at that time.
All tracks in the yard, with the exception of the 1950 freight house track which headed due south, stopped on the east side of and perpendicular to Ocean Avenue.
These sidings were all electrified, with the exception of the new, 1950-era freight house siding. All electrification was removed by 1951. (End of DD1 freight service.)
This yard and trackage was in use as late as my 1958 map. How much later it lasted, I have no idea, however, I’m sure that once the express service stopped on the LIRR, the yard (and siding) was no longer of any use.
Perhaps it was removed in the early-mid 1960s? Patchogue's freight and express houses were removed with the 1963 depot area reorganization. So, maybe around the same time.
J.J. Earl, if you’re reading, do you remember this yard and when it was last used?
Dave Keller