B Line

B Line, B-Line or Line B may refer to the following:

US

 * B (New York City Subway service), a subway route in New York
 * B-Line (Norfolk Southern), a freight-rail line in Virginia
 * Green Line B branch, a light-rail line in Boston, Massachusetts
 * B-Line Rivalry, a sports rivalry between Boston College and Boston University
 * B Line (Los Angeles Metro), a rapid transit line in Los Angeles County, California
 * B (Los Angeles Railway), former streetcar service in Los Angeles, US
 * RapidRide B Line, a bus route in King County, Washington
 * B Line (RTD), a light-rail system in Denver, Colorado
 * Butte Regional Transit, a bus system in Butte County, California
 * Metro B Line (Minnesota), a planned rapid bus line in Minneapolis-Saint Paul
 * Riverview Corridor, previously known as the B Line

Elsewhere

 * Line B (Buenos Aires Underground), an underground line in Buenos Aires, Argentina
 * B-Line (Hamilton), a proposed light-rail line in Hamilton, Ontario
 * Line B (Prague Metro), a subway route in Prague, Czech Republic
 * B-Line (Sydney), a bus-rapid-transit system in Sydney, Australia
 * B-Line (Vancouver), a bus-rapid-transit system in Vancouver, British Columbia
 * Mexico City Metro Line B, a rapid-transit line in Mexico City
 * fr:Ligne B du métro de Rennes, a future subway route in Rennes, France

Other uses

 * "B Line" (song), a track on Lamb's album Fear of Fours
 * The Eighties Matchbox B-Line Disaster, an English rock band
 * Index register, in computing, per outdated British use
 * A finding in lung ultrasound