The LIRR’s Main Line offers some rich history. From the moment the train leaves Jamaica station, it can be a pretty fast run to Hicksville, and offers a mixture of elevated, and at grade stretches. The Main Line is home to five different branches that use all or part of the 25 plus miles of track from Jamaica to Hicksville. Port Jefferson and Ronkonkoma trains make up the bulk of the LIRR’s main line. Some Montauk trains occasionally use the main line, before branching south to Babylon once it passes Bethpage station on the Ronkonkoma branch. Oyster Bay trains usually start at either Jamaica or Mineola then tail off towards the north shore upon leaving Mineola. Finally, Hempstead trains follow the main route from Jamaica to Floral park, before angling to the right, en route to its branch terminal. Port Jefferson line is a branch of the LIRR main line from Hicksville and serves Long Island’s north shore.

The current main line from Jamaica to Hicksville was complete in 1837.

The LIRR Belmont Spur runs when the racetrack is open. The line starts at Atlantic Terminal (Flatbush Avenue) in Brooklyn or NY Penn non stop to Jamaica and then non-stop via Main Line to the Park. East of Queens Village there is a switch and a turn-off track which leads to the terminal station at Belmont Park. This track also has a counterpart goingeast, forming a wye. Shortly after the single track crosses the Cross Island Parkway, it subdivides into four. The Belmont Park station has low platforms withstair steps aligning with the car doors for the passengers' use. The Belmont Park station sees regular service on race days, with trains from both Penn Station and Flatbush Avenue serving it. The station has three low island platforms It gets is heaviestworkout on Belmont Stakes day , the first Saturday in June.