US&S LED's have around since the early 2000's. Until 2008, they were mistakenly thought to be the LEDs that RSI uses, but that has been proven false.

Slowly, these are starting to pop up on light rail systems, including a single LED in Sacramento as seen in the video below.

This LED light is model HC-120B. It can operate between 6-18 volts D.C. and 5-13 volts A.C. It can operate from temperatures ranging from -40°C to +74°C (-40°F to +165°F). It claims to have a life of 100,000 hours if ran at 10 volts. It also has 6 white L.E.D. lights that are used for side lights.