Albuquerque   commuter rail (2006)

Atlanta   rapid transit (1971)

Austin   commuter rail (under construction)

Baltimore   light rail (1992), rapid transit (1983), commuter rail

Boston   light rail (1897), rapid transit (1901), commuter rail (1974)

Buffalo   light rail (1985)

Camden   light rail (2004), rapid transit (1936)

Charlotte   light rail (under construction)

Chicago   rapid transit (1892), commuter rail (1856)

Cleveland   light rail (1920), rapid transit (1955)

Dallas   streetcar (1989), light rail (1996), commuter rail (1996)

Denver   light rail (1994)

Galveston   streetcar (1893)

Harrisburg   commuter rail (under construction)

Hoboken   light rail (2000), rapid transit (1908), commuter rail

Houston   light rail (2004)

Kenosha   streetcar (2002)

Los Angeles   light rail (1990), rapid transit (1993), commuter rail (1992)

Memphis   streetcar (1992)

Miami   rapid transit (1984), commuter rail (1987)

Minneapolis   light rail (2004)

Nashville   commuter rail (2006)

Newark   light rail (1935), commuter rail

New Orleans   streetcar (1835)

New York City   rapid transit (1868), commuter rail

Oceanside   light rail (under construction)

Philadelphia   streetcar (1858), light rail (1906), rapid transit (1907), commuter rail

Phoenix   light rail (under construction)

Pittsburgh   light rail (1987)

Portland   streetcar (2001), light rail (1986)

Sacramento   light rail (1987)

Salt Lake City   light rail (1999)

San Diego   light rail (1981), commuter rail (1995)

San Francisco   streetcar (1860), light rail (1918), rapid transit (1972), commuter rail (1863)

San Jose   light rail (1987), commuter rail (1998)

Seattle   light rail (under construction), commuter rail (2000)

St. Louis   light rail (1993)

Syracuse   commuter rail (1994)

Tacoma   light rail (2003)

Tampa   streetcar (2002)

Washington D.C.   light rail (under construction), rapid transit (1976), commuter rail

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The above list was compiled by conducting a Web search for information about rail transit for each of the 100 largest urban areas in the U.S. as defined by the 2000 U.S. census. It includes urban areas that contained at least one streetcar, light rail, rapid transit or commuter rail line in operation or under construction as of January 31, 2007. The starting year of each type of service is shown in parenthesis.

Approximately 41 urban areas in the U.S. have at least one rail transit line. A few additional urban areas are preparing to begin construction (including Honolulu) and many more are considering it.

The number of such areas is only approximate because in some cases it is difficult to determine what is a separate urban area. For purposes of this survey, a city that contain an independent rail transit system is considered to be a separate urban area.

The year that service began is shown in parenthesis after the type of transit. In the case of some commuter rail systems in the eastern U.S. that began service in the nineteenth century, the exact start of service is not known and thus no year is provided.

The most common type is rail transit system is light rail, at 26 systems, and most of these (20 systems) were constructed from scratch during the past two decades or are currently under construction. Three older light rail systems (Cleveland, Newark and San Francisco) have been extended or had new lines built during the past decade.

Nine urban areas have at least one streetcar line that serves primarily a transit function (i.e., not counting several short heritage or museum lines). Of these, five were constructed during the past two decades, and three older systems had at least one additional line constructed (or reconstructed in the case of Philadelphia) during the past decade. A number of other cities are also considering adding streetcar lines. This represents a sharp reversal of the trend of eliminating streetcar lines that characterized most of the twentieth century.

All of the urban areas with relatively new streetcar systems previously had streetcar systems that were abandoned; the years listed are those of the start of the new systems. The starting year shown for the older streetcar systems is when operation began on rails with horse-drawn vehicles, not when the systems were electrified.

Rapid transit refers to systems with dedicated rights of way (mostly underground, on elevated tracks and/or on ground level) and which have high level platforms. Such systems use heavy rail vehicles, which means that they weigh much more than light rail vehicles. Twelve urban areas have rapid transit, with six of the systems having been built in recent decades (San Francisco, Washington D.C., Baltimore, Los Angeles, Atlanta and Miami). Extensions are being planned or considered for all six of the new systems as well as for most of the older systems.

Commuter rail refers to heavy rail trains that are generally operated on mainline railroad tracks and are usually hauled by locomotives. 20 of the urban areas have commuter rail in operation or under construction, of which eleven are relatively new operations. Commuter rail systems are also being planned or studied for several additional urban areas.

Three of the newest rail transit systems use DMU (diesel multiple unit) vehicles instead of electrically powered vehicles. Interestingly, two of them (Camden and Oceanside) are officially classified as light rail and one (Austin) is officially classified as commuter rail.