The Atlantic City Line is presently South Jersey's only traditional commuter railroad line and unlike the rest of the NJ Transit Railroad system it doesn't operate with peak commuter-focused schedules, and instead operates as a true Regional Rail Line, although frequency could be better. Trains operate consistently, but not with clockface schedules, every 1 to 2 hours throughout the day 7 days a week. This lack of clockface (same minutes past the hour on every trip) are to do with the fact the line is single-tracked with passing sidings not fully at regular intervals.

There are 12 round-trips per day (both on weekdays and weekends, although the schedules are slightly different between weekdays and Saturdays and Sundays). The line also doesn't connect with the rest of the NJT rail system with trains deadheading up the Amtrak-owned, regional rail operated by SEPTA Northeast Corridor, to and from North Jersey for heavy maintenance from time to time.

he line is largely not electrified with generally 3 car diesel trains operating consisting of 3 single-level Comet Coaches and an in push-pull configuration with a GP40PH-2B locomotive. The locomotive always operates on the Philadelphia-bound end of the train. This allows closer access to the station at the Atlantic City Rail terminal, and for trains to pull south and forward out of lower-level platforms at 30th Street Station in Philadelphia during layovers to allow the exhaust from the locomotive to be properly ventilated south of 30th Street Station. The Atlantic City Line service is the only fully non-electrified service into Philadelphia, although the Amtrak Pennsylvanian's engine change between diesel and electric occurs in Philadelphia, with trains on the Pennsylvanian running under wire between Philly and Harrisburg.

The current line entered service in 1989 after all South Jersey train service was discontinued in 1981. These Conrail-operated, NJDOT subsidized, trains operated using RDCs along the current Atlantic City Line between the Lindenwold PATCO Station and Atlantic City, Ocean City and Cape May, and all were discontinued on the same day in October 1981.

The goal to restore train service to Atlantic City came about nearly as soon as service was discontinued. In the 1980s Atlantic City was booming as a tourism destination due to the state's decision to legalize gambling in 1977 in Atlantic City to revitalize the struggling former seaside resort city. As a way to service this growing market New Jersey Transit and Amtrak entered an agreement to rebuild the Atlantic City Line. Starting in 1989 Amtrak’s Atlantic City Express would run one-stop (originally Lindenwold) intercity service along the line between Atlantic City, Philadelphia and continuing to a variety of destinations throughout the Northeast, including as far south as Richmond, Virginia, Harrisburg, and as far north as Springfield, Massachusetts, with New York City as the primary destination. In 1990 there was briefly direct service between Atlantic City and the Philadelphia International Airport.

At the same time, New Jersey Transit Rail Operations restored service between Lindenwold and Atlantic City opening up four intermediate stations, three at new locations as Park & Rides. These four stations all received high-level platforms with TVMs, and simple red shelters. NJ Transit originally planned to offer a proof-of-payment system for fare collection on the line to allow reduced staffing — perhaps even one person train operation with automatic doors at high platform stations — but this was never implemented, with conductors collecting and checking all tickets like on all other NJ Transit Lines (and all other legacy Commuter Railroads except Caltrain) to this day.

Amtrak's Atlantic City Express was a failure, the casino market preferred to ride discounted faster buses (with coupons for free slot play upon arrival in Atlantic City) and the service was poorly marketed. The opening of the Foxwoods Casino in Connecticut in 1992 along with numerous other casinos that followed throughout the Mid-Atlantic region, including casinos directly outside of Philadelphia in the 2000s, resulted in the 1980s and early 1990s boom in Atlantic City being short-lived and Atlantic City Express Amtrak trains seeing very low ridership, with most riders using these trains simply as an additional trains along the Northeast Corridor with the majority or ridership riding between New York and Philadelphia.

Amtrak and NJ Transit then came to an agreement in 1995 where New Jersey Transit would assume all operations and maintenance, (which Amtrak was previously covering) the Atlantic City Rail Line. On April 2, 1995, all NJ Transit Trains were extended to Phliadelphia-30th Street Station. Amtrak continued to offer thruway service via NJ Transit Train to Atlantic City with the rail schedule appearing in Amtrak timetables, and Amtrak selling combined tickets via its ARROW reservation system on NJ Transit trains. As of 2024 these combined tickets can't seem to be purchased via the Amtrak website with a notice that they are only available at an Amtrak station or by calling 1-800-USA-RAIL. They were available until the mid-2010s on the Amtrak website, but I think these are one of the last trips requiring paper tickets and Amtrak's poor website updates prevent this purchase.

Through express rail service from New York to Atlantic City was attempted again by the NJT-operated, the Casino Reinvestment Development Authority-funded ACES Express. This operated from February 2009 to September 2011 with trains needing to reverse direction from the Northeast Corridor into Pennsylvania to cross the Delair Bridge back into New Jersey, with one intermediate stop in Newark. This special train service was operated by New Jersey Transit, but tickets were sold through Amtrak's ARROW reservation system. ACES' Trains used eight specially purchased and retrofitted Bombardier MultiLevel Coaches with 2 by 1 first class seats and more comfortable reclining leather coach seats. There was even separate party compartment that could be booked by a larger group. Trains operated with a regular ALP46s for the section along the Northeast Corridor, and a separate P40DC (purchased form Amtrak) Diesel locomotive at the opposite end of the train for service along the diesel Atlantic City Line. I regret not riding or photographing this unique train when it was in operation. I do remember seeing it on the big board and hearing the announcement for it once in the main Amtrak concourse in New York-Penn Station.