The city’s three existing streetcars are being tested on a special track in Southeast Washington. (Robert Thomson/The Washington Post)

After blowing an earlier self-imposed deadline, Mayor Vincent C. Gray is back with a new prediction for the debut of streetcar service along H Street and Benning Road NE.

“We’ll have passenger service probably starting in January, not later than early February when we get an additional car,” Gray said during his monthly appearance on NewsChannel 8.

D.C. transportation department officials finally admitted last month that the earlier goal of starting service by year’s end wasn’t going to happen. Work continues today on various parts of the system — including hanging the overhead wires, building the car barn near the line’s eastern terminus and finishing a turnaround switch at its western terminus. And the city is still waiting on the delivery of two streetcars to add to the three already delivered and in testing.

On Thursday, transportation officials started using a “hi-rail” truck to “simulate streetcar activity” before beginning tests with the actual streetcars next month.

Asked if the transportation department is on the same page as Gray in terms of the grand opening date, spokesman Reggie Sanders said in an e-mail, “Yes. Absolutely.”