The Orange Line was back online as of about 5 p.m. Monday afternoon, after a two-hour service suspension due to a medical emergency at Ruggles station, the Massachusetts Bay Transportation Authority said.

MBTA officials told travelers to use the Green Line for downtown service. Handicap-accessible shuttle buses were provided between Jackson Station and Copley Station on the Green Line, according to alerts.

All other T lines were operating regularly as of 4 p.m. Monday. Commuter rails are all on time, except for the Franklin and Lowell lines, where trains are running 15 to 25 minutes behind schedule.

Buses have so far escaped severe service delays, though evening commuter traffic is causing minor to moderate delays on 27 bus lines.

No major accidents are clogging the lines' exodus out of the city — the Mass Turnpike and Route 93 — though typical slowdowns are keeping speeds low, according to real-time Mass Department of Transportation traffic maps.