The only grade crossing that would stand is Main Street which sees the actual convergence point where the Oyster Bay Branch diverts to the North. It is located next to NASSAU tower, and as far as the pedestrian crossing, I think it is still in service. However, a temporary pedestrian bridge will be placed there, which would eliminate it. They say they will not close Main Street until AFTER Willis Avenue's project is completed 9-10 months from now. Main Street will see the same fate as 12th Street in New Hyde Park: Closed permanently to traffic as if a crossing never existed there.
Two box tunnel or U-shaped bridges will be constructed on site (one for the Main, and one for the OB), but both will not be box-jacked into place simultaneously. Sometime in Summer 2021, there will be two consecutive weekend outages to push one on one weekend, and the next would see the second pushed in. It will be done in three phases: Excavation to the South of Willis Ave. (MAIN), excavation to the North of Willis Avenue (OYSTER BAY), and the area in between the two crossings. This is the first time I think since 1980, that two grade crossings will be eliminated in the same town at the same time (Massapequa Park was last). Having Urban and Covert doesn't count because they are in two different towns.
This station is Babylon, this is the train to Penn Station. Stopping at: Lindenhurst, Copiague, Amityville, Massapequa Park, Massapequa, Seaford, Wantagh, Bellmore, Merrick, Freeport, Baldwin, Rockville Centre, Lynbrook, Valley Stream, Jamaica, Kew Gardens, Forest Hills, Woodside, Penn Station.