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.