The Brigantine railline split off the Atlantic City Railroad just before Pomona Road in the Pomona section of Galloway Twp and proceeded due east along what is now Great Creek Road. It crossed through what is now the Forsythe Wildlife Refuge (the public access road in the Forsythe refuge is the former rail bed), went over Grassy Bay and entered Brigantine Island near where the Brigantine Golf Course is currently located, actually bisecting the fairway of hole #17. It then proceeded towards the ocean roughly along what is now Roosevelt Boulevard, with the station near the intersection of Brigantine Avenue & Roosevelt. Length of track from Pomona to Brig Station was approximately 14 miles. It was occasionally referred to as "swamp siding".
Storms damaged the trestle over Grassy Bay around the turn of the century (the exact date escapes me) and it was never rebuilt.
There was also a trolley line operated by Brigantine Transit Co. that travelled the length of Brigantine Island.
Some more details (with a photo or two) can be found in the book Railroading in Atlantic County by Andrew Russell c.1981, which can be found at the Atlantic County Library in several branches.
And here:
http://www.brigantinebeachnj.com/history.html