I want to know the answer to the following question:
When did Houston start using light rail lines?
All the background I'm provided with is that "METRO began light rail service on January 1, 2004, with the inaugural track ("Red Line") running about 8 miles (13 km) from the University of Houston–Downtown (UHD), which traverses through the Texas Medical Center and terminates at NRG Park.". Is that enough to answer the question?
Answer: yes