The B1 (commonly known as Guangzhou Metro Line 3 Trains) is a class of rolling stock built for Line 3 of Guangzhou Metro. They are built by Siemens Mobility and CSR Zhuzhou Locomotive. B1 is the first mass-produced B-class rolling stock for the Guangzhou Metro. They entered service on 26 December 2005.
B1 sets are double-paired for service since 20 April 2010, to expand the service capacity of Line 3.
The B1s feature Siemens traction motors, Knorr EP-2002 electronic braking systems, plug-style doors and electronic strip maps.
The B1 contract was awarded to Siemens Mobility on 19 May 2003, who won the A1 contract before. The first train completed on 18 November 2005.
On 8 January 2010, the first train (set 03x001-002) received an overhaul at Xiajiao Depot.