There it was again, after all these years: an Amtrak passenger train, its red and blue cars gleaming in the moonlight as it idled at a platform in Mobile, Ala.

An eager crowd had gathered before dawn on Monday, ready to board the train for its inaugural trip on the restored Gulf Coast line, newly christened the Mardi Gras Service, between Mobile and New Orleans. And many more travelers were waiting at stations along the way.

Two decades after Hurricane Katrina decimated entire coastal communities and wiped out passenger rail service along the Gulf Coast, the return of Amtrak this week — with two trains daily in each direction — sent a jolt of excitement down the coast.

“It’s almost like it’s one more step toward the healing,” said Charlotte Welco, 60, who boarded in New Orleans with her mother in the afternoon, bound for Biloxi, Miss., near her home in Ocean Springs. “This is just something else to get us excited.”

The trains also stop in the Mississippi cities of Pascagoula, Gulfport and Bay Saint Louis during a journey that takes about four hours in all. At a peak speed of about 79 miles an hour, it is not particularly fast, compared with some of its international counterparts.

But that didn’t seem to matter as the 6:30 a.m. train out of Mobile prepared to trundle through the shipyards, mossy woods and marshlands that line the coastal route.