BWI Airport Station is an intermodal passenger station in Linthicum, Maryland near Baltimore–Washington International Airport (BWI). It is served by Amtrak Northeast Corridor intercity trains, MARC Penn Line regional rail trains, and several local bus lines. Located just over a mile from the airport's terminal, the station was the first intercity rail station in the United States built to service an airport. A free shuttle bus runs between the station and the airport terminal at all hours. Although Penn Station is the Baltimore area's main intercity station, BWI Airport is a major station in its own right. It is Amtrak's sixth-busiest station in the Mid-Atlantic region (behind New York Penn, Washington, Philadelphia, Baltimore Penn and Albany-Rensselaer), the third-busiest in the Baltimore-Washington corridor, and the 12th busiest nationwide. History First proposed in 1964 by Charles Adler, a Baltimore-based inventor of traffic and aircraft safety devices, the station was dedicated on October 23, 1980coincidentally, mere hours after Adler's deathand opened for Amtrak intercity and Conrail (now MARC) commuter trains three days later. The station's building houses a ticketing desk, waiting room, and a concessions area. The adjacent parking garage is used by commuters who ride the train to work in Baltimore or Washington, and also contains the bus stop for shuttles to the BWI terminal. The garage was built in the late 1990s to replace a smaller surface lot. It contains 3,200 parking spaces and typically does not fill to capacity. The Carolinian served the station between 1991 and 2004. Platform renovations The high-level platforms were rebuilt and lengthened between 2006 and 2010. The existing structures were replaced with new precast concrete segments, and new signs, lights, shelters, railing, canopies, and benches were installed. Expansion In 2010, $9.4 million was allocated for design and engineering of a new station building and fourth track, which was then expected to cost $80–100 million. MDOT requested $300 million in federal funds for the project in 2011, but the request was denied. The Federal Railroad Administration issued a Finding Of No Significant Impact—a major step in the environmental review process—in February 2016, clearing the way for final design and construction to begin after funding was obtained. The project was then expected to cost $600 million and include of fourth track. On August 27, 2018, the MTA began a $4.7 million project to rebuild and enlarge the station. A temporary station building was used during construction The