Mr NJ: Freight rail passes thru three of NOLAs public parks, each of which can be reached by streetcar. The Public Belt R.R. which handles goods for the wharves runs along the waterfront the length of the city. This includes the French Quarter waterfront from Esplanade Av to Canal St; the wharves in the area between Jackson Sq and Canal have been replaced by Woldenberg Park. There is freight traffic along this park frequently, which lies between Decatur St and the river. The Riverfront streetcar utilizes a portion of the Belt RR, so riding on that car ought to give you a good look.
Much further uptown, the Belt RR passes through Audubon Park close by the NO Zoo. When you ride on the St Charles line, the park is located directly across from the main entrance to the Tulane University campus. To reach the tracks, you'll have to walk down through the park to reach the section that lies between Magazine St and the river. It's a couple hundred yards but it is a beautiful park.
If you don't want to do the walking you can stay on the car just a bit further to where it reaches the Riverbend. The car turns here 90 degrees, to leave St Charles Av for Carrolton Av. This is where the car tracks pass closest to the river and to the Belt RR tracks as well, after they come out of Audubon Park. La Madeline's bakery and Cooter Brown's Bar and Grill have outside cafe seating so you can watch from the sidewalk.
Rail freight also runs through City Park, along the river side of I-610. City Park is located at the end of the City Park branch of the Canal line. The car stop is at the entrance of the NO Museum of Art. Again, you'll have to walk thru the park to reach the rail line. I'd think a standard tourist brochure ought to show the outlines and locations of these three parks.
I don't know which of the two lines is more busy: the waterfront or the one along 610. I guess the run through City Park is to bypass the wharves for traffic that need not go there; or to reach the yard where they form up the Belt RR trains.
Regards, bulleit