REVERE (CBS) – An excavator fell through a bridge under construction in Revere Saturday morning.

It happened on the Winthrop Avenue Bridge along Route 145 around 6:30 a.m.

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State Police say the operator, a 50-year-old man from West Bridgewater, was not seriously hurt.

The bridge had been shut down in both directions for weekend repair work.

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The MBTA was already busing commuter rail riders around the closed rail line under the bridge.

The bridge was due to re-open Monday at 5 a.m. with reduced capacity, according to the city of Revere.

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A MassDOT spokesman told WBZ-TV, “they expect the situation to be resolved in time for the originally scheduled reopening.”