The SD-100 and SD-160 are light rail vehicles manufactured by Siemens. The SD-100 uses motors that run on direct current electricity motors, while the SD-160 model features newer motors that run on alternating currentmotors. Both models are suited for passenger loading at street, and at high-platform, levels. Both models are in use various cities in North America, such as San Diego (SD-100), Salt Lake City (both models), Denver (both models), Calgary (SD-160) and Edmonton (SD-160). The Siemens SD-100 is no longer in production, while the Siemens SD-160 is still in production for the C-Train light rail system.
The SD-160's dimensions are 24.802 metres (81.37 ft) by 2.654 metres (8.71 ft) by 3.811 metres (12.50 ft) and can be joined together to form trains of up to six cars in length. It is powered by four AC motors which provide a maximum of 580 kW and a maximum speed of 80 kilometres per hour (50 mph). It accelerates at 1.07 m/s² and decelerates at 1.31 m/s², with emergency braking deceleration of 2.63 m/s². The brakes also serve as a generator, regenerating power back to a city's electrical lines. The SD-160 has a passenger capacity of 236 passengers (standing) with 64 seats.
Compared to its predecessor, the Siemens–Duewag U2, the SD-160's driver's cabin is significantly larger, but its total length is still less than 25 metres (82 ft), allowing three vehicles to be combined and still be under the 75-metre (246 ft) maximum length of a German streetcar train assembly. Each vehicle also features an onboard closed-circuit TV security camera system for increased passenger safety. Unlike the Siemens SD-100, the Siemens SD-160 does not use the bi-folded doors, instead using sliding doors similar to designs featured on the Siemens S70. In addition, both can be used together in mixed trains consisting of SD-100s and SD-160s. The new, streetcar-length S70 cars ordered for San Diego are designed to be compatible with the SD-100, allowing the SD-100 to operate in a mixed consist, sandwiched between two S70 cars.