Bay St. Louis (CSX Bridge)

The CSX swing bridge at Bay St. Louis offers one of the Gulf Coast's most accessible railfanning experiences. The bridge crosses the mouth of St. Louis Bay at milepost 752.6 on CSX's NO&M Subdivision, connecting Bay St. Louis on the west with Pass Christian to the east. Viewing is straightforward: the public beach and waterfront along Beach Boulevard put you within a few hundred feet of the tracks, and the historic L&N Train Depot at 1928 Depot Way — now the Hancock County Visitors Center and Amtrak station — sits right beside the line.

The bridge itself is a swing-type drawbridge with 13 feet of vertical clearance in the closed position and 100 feet of horizontal clearance for marine traffic. It opens for vessels roughly six times per day, which can delay trains but also gives railfans the rare sight of a railroad bridge in motion. Since 2022, the bridge has been operated remotely from CSX's control center in Mobile, Alabama, using infrared cameras and closed-circuit TV. Trains cross the single-track bridge at restricted speed, giving photographers ample time to capture the full consist against the open water backdrop.

Since August 18, 2025, Amtrak's Mardi Gras Service has added four daily passenger train movements (two round trips between New Orleans and Mobile), bringing scheduled action to complement the freight traffic. The Bay St. Louis station stop is right at the depot, making this an ideal spot to combine railfanning with an Amtrak day trip.

Bay St. Louis sits at sea level on Mississippi's Gulf Coast, roughly 60 miles east of New Orleans. The waterfront is characterized by white sand beaches, live oaks draped in Spanish moss, and the wide expanse of St. Louis Bay stretching toward Pass Christian. The railroad bridge runs low across the water — just 13 feet above mean high water in the closed position — making trains appear to glide across the surface of the bay.

The surrounding town has the relaxed character of a Gulf Coast artist colony. Old Town Bay St. Louis, clustered along Main Street and Second Street just blocks from the tracks, features galleries, restaurants, and the 1928 mission-style L&N Depot that now serves as the visitor center, Mardi Gras Museum, and Alice Moseley Folk Art Museum. The depot was notably the centerpiece of the 1966 film "This Property Is Condemned" starring Robert Redford and Natalie Wood. Pelicans, shrimp trawlers, and recreational boats share the waterway with the railroad bridge, creating a dynamic coastal scene. Summer brings heat and humidity tempered by Gulf breezes, while winter offers mild temperatures and crisp visibility ideal for long-range photography across the bay.

The NO&M Subdivision is CSX's sole rail corridor between Mobile, Alabama, and New Orleans, Louisiana — a distance of 138.5 miles. All east-west CSX freight traffic along the Gulf Coast funnels through this single-track line. The corridor handles more than 30 million gross tons of freight annually, predominantly manifest and intermodal trains moving between the Mobile terminal complex and New Orleans Gateway.

The biggest development in recent years is the return of passenger rail. Amtrak's Mardi Gras Service launched on August 18, 2025, with two daily round trips between New Orleans and Mobile, stopping at Bay St. Louis, Gulfport, Biloxi, and Pascagoula. The service drew 46,000 riders in its first three months, exceeding projections and achieving a 96% customer satisfaction rate — the highest of any Amtrak route. This is the first regular passenger service on the Gulf Coast since Hurricane Katrina knocked out the Sunset Limited's route in 2005, and the first dedicated corridor service since the Gulf Coast Limited ran in 1996-1997.

The swing bridge itself is a bottleneck that creates bunching of traffic — trains must wait while the bridge opens for marine vessels approximately six times daily. This means you may experience quiet gaps followed by rapid-fire action as delayed trains queue up and cross in succession.

The Bay St. Louis waterfront offers several public vantage points for photography. From the beach along Beach Boulevard west of the bridge, you can shoot eastward with trains crossing the bridge against the sunrise — a 100-200mm telephoto lens compresses the train against the open water effectively. The bridge runs roughly east-west, so morning light illuminates eastbound trains from the side, and afternoon light favors westbound consists.

The area near the L&N Depot and Amtrak station platform at 1928 Depot Way provides a close-up perspective as trains pass through town before or after the bridge crossing. This angle works well for capturing Amtrak Mardi Gras Service trains with the mission-style depot in the frame.

For wider contextual shots, the U.S. 90 highway bridge (St. Louis Bay Bridge) runs parallel to and just south of the railroad bridge, and views from Beach Boulevard on the Pass Christian side can frame the entire railroad bridge span. Be aware that wind off the bay is constant — use a wind filter on microphones for video, and bring a sturdy tripod. The flat, low-elevation terrain means heat shimmer can be an issue on hot summer afternoons; morning shoots generally produce sharper images.

The railroad line through Bay St. Louis dates to 1870, when the New Orleans, Mobile & Chattanooga Railroad (NO M&C) completed its coastal route by driving a golden spike at Chef Menteur Pass on October 29, 1870, linking New Orleans to the Mississippi Gulf Coast. In the mid-1870s, the NOM&C joined forces with the Louisville & Nashville Railroad (L&N), which eventually leased the entire line and operated it as a division. The L&N built the existing depot in 1928 in a distinctive mission style — it is now designated a Mississippi Landmark.

The bridge across St. Louis Bay has been rebuilt multiple times following hurricane damage. Hurricane Camille in 1969 and Hurricane Katrina in 2005 both inflicted severe damage. After Katrina, CSX mobilized crews the very next day. Project Manager Billy Baughman set up at Washington Street with 40 workers and hired 60 local residents. CSX had a work train crossing the repaired bridge within approximately four months — far faster than the adjacent U.S. 90 highway bridge, which took until May 2007 to reopen. The L&N merged into the Seaboard System in 1982, which became CSX Transportation in 1986.

The return of Amtrak passenger service in August 2025 via the Mardi Gras Service marked the end of a nearly 20-year absence of passenger trains on this route following Katrina.

Bay St. Louis stands out among Gulf Coast railfanning spots for several reasons. First, the combination of a working swing bridge over open water with unrestricted public beach access is exceptionally rare — most coastal rail bridges are fenced off or inaccessible. Second, the addition of Amtrak Mardi Gras Service in 2025 means this is now one of the few spots on the Gulf Coast where you can photograph both freight and scheduled passenger trains. Third, the adjacent historic L&N Depot — now serving as the Amtrak station — creates a connection between modern railroading and 150+ years of railroad heritage that few locations can match. Finally, the town's character as an arts-oriented beach community means railfans have excellent food, galleries, and lodging options within walking distance of the tracks, making this a spot where non-railfan travel companions will be perfectly content.