In anticipation, all stations that were still at grade level had their platforms converted from low-level to high-level (an increase of 4 feet) from late-1967 to late-1968 in time for when the fleet went into service.

Stations that were still at-grade at the time were Lindenhurst, Copiague, Amityville, Massapequa Park, Bellmore, and Merrick.

The call for high-level platforms was due to the M1 lacking steps that the fleet they were replacing had, and to make travel times quicker by several minutes.

The stretch of track between Amityville and Lindenhurst was grade-separated, with new high-level platforms on elevated viaducts, on August 7, 1973.

In 1977, work began on the $29.5 million project to elevate the line through Massapequa Park to eliminate the three remaining grade crossings.

As part of the project, a temporary wooden platform at the station's eastern end would be demolished and replaced by a 300 foot (91 m)-long concrete slab.

[4] Media related to Babylon Branch (Long Island Rail Road) at Wikimedia Commons