SS3B, a new type of heavy load freight locomotive, developed by Zhuzhou Electric Locomotive Works in 2002 for Chinese Ministry of Railways, is 12-axle type based on SS series locomotives. MoR placed an order up to 80 SS3B locomotives for freight car traction with the delivery time before the first half of 2003.

SS3B locomotive is composed of two identical 6-axle locomotives by internal coupling, with each unit forming a complete system.

A traction transformer and two rectifiers are installed on each unit of SS3B. Each rectifier energizes three shunted DC traction motors, which can be isolated individually in case of failure to ensure normal performance of other motors so as to enhance utilization of locomotive.

Regarding its air brake, DK-1 E-P brake for SS series locomotives is adopted while backup resistance braking is employed for its dynamic brake..

Control system of SS3B is structured by two-pole network of train bus and vehicle bus. Multiple operation control and information exchange between two units are fulfilled through WTB (wired train bus) with double redundancy and automatic changeover. MVB (multiple vehicle bus) is used to connect each control unit inside the single locomotive.

Driving / Braking characteristics

Type ZQ800-1 Rated power 800 kW Rated voltage 1550V Max. voltage 1800 V Rated current 550A Max. current 830A Rated rev. 920 r/min Max. rev. 1920 r/min Insulation grade H/F Pole 4 Cooling method Forced cooling through exterior ventilation