BART on Twitter: "Yellow Line service between Pleasant Hill and Concord will be single-tracking all day today. Please plan extra time for travel if traveling through area. Crews will be replacing worn-out
In Concord, a track meet like no other - The Boston Globe
Concord Beacon 50W Mains Voltage LS1 Three circuit track in Black – The Lamp Company
Taking a Trip Down Memory Lane: We Tracked Concorde! - RadarBox.com Blog