CHAFFEE, Mo. (AP) -- A Missouri transportation official says it will likely cost about $3 million to replace the highway overpass that partially collapsed when rail cars smashed into one of its support pillars after a cargo train collision.

Seven people in two cars on the Highway M overpass in Scott County were injured, none seriously, when two 40-foot sections of the overpass crumpled early Saturday.

The collapse occurred after a Union Pacific train hit the side of a Burlington Northern Santa Fe train at a rail intersection. Derailed rail cars then struck columns supporting the overpass, causing the collapse.

Mark Shelton, engineer for the Missouri Department of Transportation, said Sunday that the bridge replacement is estimated to cost about $3 million, and the bridge is expected to reopen in early September.

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