A detour is still in effect in the southbound lanes of the Northeast Extension between Mahoning Valley and Lehigh Valley.

An electrical beam has collapsed onto several cars inside a highway tunnel in Pennsylvania, causing a major traffic backup.

Police say no one was injured when the beam fell inside the Lehigh Tunnel around 6 p.m. Wednesday. 

Turnpike electricians are working to repair the beam.

Police say they hope to reopen the southbound lanes by morning rush hour.