BOSTON (CBS) – State Police are investigating a crash that damaged wires in the ceiling of the Tip O’Neill Tunnel.

A flatbed truck carrying a box truck was headed southbound on Route 93 when the top of the box truck struck the ceiling of the tunnel.

The crash, which happened at 9:40 a.m., caused some minor traffic back-ups.

Some damaged wires needed to be removed from the tunnel ceiling.