FALMOUTH — Drivers who use Route 26/100 should expect periodic delays on Wednesday and Thursday while construction crews unload steel beams that will be utilized in the construction of a bridge.

Crews will close the bridge for 20 minutes each day at 9 a.m. and 1 p.m., the Maine Department of Transportation announced Tuesday afternoon.

The 834-foot Railroad Crossing Bridge, built in 1932, spans the Presumpscot River and the Pan Am railroad line near the Portland city line.

This is the next step in construction for the bridge being built downstream of the existing bridge. Construction is expected to be completed by the fall of 2011. Once the new bridge is opened, crews will dismantle and remove the old bridge.

The total cost of the bridge replacement project is $10.5 million. CPM Constructors of Freeport is the contractor.