Commuter train line in South Florida, running from Mangonia Park in West Palm to Miami International Airport. It is a joint venture of Dade, Broward, and Palm Beach County, and uses a single seventy-mile track that is occasionally shared with Amtrak's Atlantic Coast trains.

The Tri-Rail's single track is one of its main drawbacks: it severely limits the line's capacity, especially when Amtrak has to pass through. A second Tri-Rail track is currently in the works, and mandates replacing scores of level crossings. Some northern stretches of the second track have already been constructed.

Another problem with the Tri-Rail is that its airport stations in West Palm, Fort Lauderdale, and Miami are actually quite far from the terminals, requiring connecting shuttle bus service. Fort Lauderdale is currently designing a light rail to link the terminals to the train station, but Miami and West Palm have been slower to respond.

Tri-Rail trains have double decker cars and diesel engines: they are comfortable, but fairly slow, and constantly blow their whistles. Still, it's a great way to get around the area if you don't want to drive, and it connects to Miami's Metrorail line that runs to downtown and points south.