SAN DIEGO (KUSI) – Transportation leaders and transit advocates from around the region gathered Tuesday to witness the first trolley on the Mid-Coast Extension of the UC San Diego Blue Line. The milestone signifies that train testing is beginning and that the San Diego Association of Governments is officially transferring responsibility to the San Diego Metropolitan Transit System for operations. “This is an important day,” said Nathan Fletcher, MTS board chair and San Diego County supervisor. “We get the keys to Mid-Coast and it’s all- systems-go for testing our trolleys on the tracks. “The public will see more and more of San Diego’s famous red trolleys testing on these tracks over the next several months,” he continued. “MTS will be working hard to train staff to get ready for the November launch.”