UPDATE: Granite Ave. Bridge back down after spending an hour stuck in upright position

(4:14 p.m.) - UPDATE: The Granite Avenue drawbridge is back down, according to a Massachusetts Department of Transportation spokesman.

The bridge spent an hour in the upright position due to one of its "locking pins" sliding out of place. The bridge's pins have been reset, the spokesman said.

(3:35 p.m.) — The Granite Avenue drawbridge over the Neponset River is currently closed— presenting a potential traffic headache for Friday afternoon commuters. The bridge- which is right off the expressway at exit 11B- is stuck in the upright position.

State Police blocked traffic from exiting the southeast expressway at Exit 11B. Mass DOT officials say inspectors are en route to the scene and that State Police and Boston Police will assist with traffic.

An eyewitness says that the safety gates have blocking traffic from passing over the bridge since about 3 p.m.