The Charm City Circulator, Baltimore's long-awaited and long-delayed free downtown shuttle bus system, will make its debut today. The Baltimore Transportation Department will launch the Circulator by beginning service on its east-west Orange Route between Hollins Market and Harbor East via the Inner Harbor. It plans to start two other routes - a north-south route between Penn Station and Federal Hill and a route connecting Johns Hopkins Hospital with Harbor East and City Hall - in the spring. Buses on the routes are scheduled to arrive at 10-minute intervals. One of the key initiatives of Mayor Sheila Dixon's transportation-minded administration, the Circulator will hit the streets just five days after the announcement that the mayor would step down from office next month as part of a plea bargain of in her public corruption case. Dixon spokesman Scott Peterson said the mayor is expected to show up for today's start. "She's still the mayor, and the Circulator was an accomplishment of this administration, so I hope she does," he said. "It's a big deal for the city."