Stations have been refurbished between downtown and Old Town to accommodate the low-floor cars used on the route, according to the Metropolitan Transit System and San Diego Association of Governments announced Sunday.The extension eliminates the need for a transfer. The Green Line used to run between El Cajon and the Old Town Transit Center, and passengers bound for downtown or Petco Park had to switch to the Blue Line."With the Green Line coming downtown, people all over San Diego can now reach the downtown area more conveniently," said Harry Mathis, the MTS chairman. "This event also marks about the halfway point in a major reinvestment of our trolley infrastructure, which will bring low-floor cars and modern stations to our entire trolley network."The modern railcars allows for quicker exiting and boarding, particularly for disabled passengers, which will mean faster rides, according to the MTS. The agency also believes that eliminating the Old Town transfer will shave 12 minutes off a trip from Mission Valley to Petco Park.The extension is a component of a larger, $720 million project to upgrade the entire trolley system and is expected to be completed in three years. The overall project will add 65 of the new railcars to the trolley fleet, which now numbers 11.Additional railcars will be added to the Orange Line -- from Santee to downtown -- next spring, and the Blue Line -- between Old Town and the border -- in 2014.The project is funded by a mix of the TransNet half-cent sales tax, bond proceeds and federal stimulus money.