The NY 27 (Sunrise Highway) LIRR overpass was replaced and completed around 1965. Looking at a Dave Keller photo from the Trains are Fun website, if you scroll down to the 28 APR 1963 photo of a MU train nearing Amityville you can see 4 tracks, which most likely represent the alignments to the old and new LIRR overpasses for NY 27.
http://www.trainsarefun.com/lirrphotos/ ... BRANCH.htm
The Amityville depot was demolished in 1964 in anticipation for the grade crossing elimination project and a temporary depot constructed (exisiting low platforms remained). Several years later in 1968, the temporary tracks were laid and a wooden temporary station with high platforms was constructed with one passenger overpass (the first temporary depot building lasted from 1964-1968, the second temporary depot lasted from 1968-1973). The same high platform and pedestrian overpass design used at Amityville was used at Copiague and Lindenhurst. The Lindenhurst depot was relocated in 1968 and moved a few blocks away where it is now on display as a museum. The Copiague depot was razed DEC 1967. 1968 was the year the M-1 was introduced and South Shore stations needed high platforms installed and started installing them in early 1968. I have seen many photos before and during the Amityville elevation, and have not come across one with an M-1 at the temporary station (but have seen photos of Merrick/Bellmore & Massapequa Park with a M-1 stoped at the temporary stations).
Now, at Merrick and Bellmore, wooden high platforms were also constructed in 1968. At Merrick, the original station location was between Merrick and Hewlett Avenues. When the 1968 high platforms were constructed, they were built just west of Merrick Avenue with one passenger overpass. During summer of 1969, temporary tracks were laid south of the Montauk Branch from the just east of the Meadowbrook Pkwy to the Wantagh Pkwy for the grade crossing elimination project. As a result, new temporary stations for Merrick and Bellmore were contructed in 1969 with high platforms. They were painted red and also each had one passenger overpass. Due to delays in funding from Albany, construction of the new elevated tracks for Merrick/Bellmore did not commence until February 1973, completing in June 1975.
At the Massapequa Park location, temporary tracks were laid in late summer 1977, south of the existing Montauk Branch from just east of the Massapequa Station to just west of the NY 27 (Sunrise Highway) overpass. As a result of the steep grade, the Unqua Road grade crossing was closed and converted to a pedestrian/bicycle gated crossing (no vehicles could use Unqua Road from 1977 to 1980) while the temporary tracks were in service. The temporary station design was identical to the Merrick/Bellmore temporary stations with wooden high platfroms painted red, but with two pedestrian overpasses with a capabilty to platform 12 M-1 cars. Train speed limit through the construction zone was 60 MPH. Back in the mid-1960's, the Montauk Branch speed limit from Babylon to Jay was 65 MPH (not sure when it was raised to 80 MPH, probably occurred sometime after M-1's were placed in service).
Amityville/Lindenhurst/Copiague do not look like today's New Hyde Park or Merillon Avenue Stations which have concrete slab high platforms on cylindrical bases with no pedestrian overpasses. I have a photo of New Hyde Park from Oct 1966 and it does show wooden high platforms painted green at that location. I would say closest thing to old Amityville now with it's former 5 grade crossings and turn of the 20th century depot would be Farmingdale.