The reopening of the Mt. Washington Transit Tunnel has been pushed back.

Pittsburgh Regional Transit announced late last week that the tunnel, which allows buses and light-rail trains to travel underneath Mt. Washington from the South Busway and South Hills Junction station to Station Square, will be reopening later than expected.

PRT closed the tunnel earlier this year so that crews could replace the tracks, restore the roadway inside the tunnel, and repair the overhead electric lines that power light rail vehicles. 

The tunnel was originally supposed to reopen by the end of October, but PRT said workers identified a design problem that required crews to adjust the newly installed sections of track.

"Following a necessary refinement of the original design, the tracks at the inbound end of the tunnel are being adjusted to meet PRT's precise operational and safety standards," PRT said.

PRT says it's actively pursuing reimbursement of excess costs from the design consultant on the project. 

Until the tunnel reopens, the 'T' will continue to use detour routes through Pittsburgh's Allentown neighborhood. 

It's unclear when the tunnel is expected to reopen, but PRT says it expects to have a new timeline by mid-November.