RTA Rapid Transit is a rapid transit

Rapid transit

A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 and light rail

Light rail

Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

 system in Cleveland

Cleveland, Ohio

Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...

 and Cuyahoga County

Cuyahoga County, Ohio

Cuyahoga County is a county located in the state of Ohio, United States. It is the most populous county in Ohio; as of the 2010 census, the population was 1,280,122. Its county seat is Cleveland. Cuyahoga County is part of Greater Cleveland, a metropolitan area, and Northeast Ohio, a...

 owned by the Greater Cleveland Regional Transit Authority

Greater Cleveland Regional Transit Authority

The Greater Cleveland Regional Transit Authority is the public transit agency for Cleveland, Ohio, United States, and the surrounding suburbs of Cuyahoga County. RTA is the largest transit agency in Ohio, providing over 44 million trips to residents and visitors of the Cleveland area in 2010...

 (RTA). The system comprises three lines—the Red Line

Red Line (Cleveland)

The Red Line is a rapid transit line of the RTA Rapid Transit in Cleveland, Ohio, running from Cleveland Hopkins International Airport northeast to Tower City in downtown Cleveland, then east and northeast to Windermere...

 (rapid transit) and Blue and Green Lines (light rail).
All four (Red, Green, Blue and Waterfront) lines join at Tower City Center

Tower City Center

Tower City Center is a large mixed-use facility located on Public Square in downtown Cleveland, Ohio. The facility is composed of a number of interconnected office buildings, including the landmark Terminal Tower, a shopping mall, two hotels, and the main hub of Cleveland's three rapid transit lines...

 in downtown Cleveland

Downtown Cleveland

Downtown Cleveland is the central business district of the City of Cleveland and Northeast Ohio. Reinvestment in the area in the mid-1990s spurred a rebirth that continues to this day, with over $2 billion in residential and commercial developments slated for the area over the next few years...

, the former Cleveland Union Terminal. From Tower City to East 55th

East 55th (RTA Rapid Transit station)

East 55th is a station on the RTA Red, Green and Blue Lines in Cleveland, Ohio, USA. The station entrance is located on the west side of East 55th Street just north of the intersection with Bower Avenue and the eastern terminus of Interstate 490....

 the three (Red, Green and Blue) lines share track and stations.