The 1.3-mile line was tested Monday morning and should start rolling next month.

Seattle Mayor Greg Nickels, King County Metro Transit officials and the streetcar manufacturer attended the trolley’s first test run. The mayor boarded the streetcar and got behind the controls to take the test car for a short drive down the tracks and then back.

The $51 million project will serve the neighborhood where Paul Allen's Vulcan company is developing a biotech center. The south Lake Union trolley will run from the Fred Hutchinson Cancer Research Center to downtown, near the Westin Hotel.

City officials said the car will connect two revitalized neighborhoods and provide residents and visitors with an environmentally-friendly method of transportation.

While the testing is underway, officials are reminding the public to keep a safe distance from the streetcars that have been painted bright red, orange and purple so they stand out.

Riders will pay $1.50 per trip.