The Wabash Tunnel that's still very lightly used after two years is becoming a bigger headache for the Port Authority.

The board's Engineering and Construction Committee has recommended extending a contract with a private company to operate and maintain the 103-year-old hole under Mount Washington for another year.

While the $575,000 price is below the $780,000 a year that Bruce & Merrilees Electric Co. has been receiving, it is to come out of the authority's troubled operating budget that faces a $31.5 million deficit beginning Jan. 1. The contract previously was paid out of its capital budget, where state and federal agencies have paid virtually the entire bill since construction was finished but they have no further funding obligations.

The single lane in the narrow one-time railroad tunnel between Route 51 and Station Square is reversible, operating inbound during the morning rush hours and outbound during the afternoon rush hours for high occupancy vehicles. All motorists can use it during non-rush hours.

Bruce & Merrilees provides a supervisor and workers to monitor traffic, change gates and signs that control the one-way flow of traffic, respond to accidents, clear snow and do general maintenance.

The contract extension empowers the Port Authority to reduce the private firm's duties after it explores alternatives for reducing costs, including the possibility of converting the Wabash Tunnel to outbound use only, 24 hours a day.

"Another alternative is to shut it down completely," board member Jim Dodaro said.

An April survey by the Pittsburgh Post-Gazette counted 123 HOVs using the tunnel during the 6 to 10 a.m. rush hours. Traffic counts determined it costs $12 a trip for every vehicle traveling the rebuilt tunnel, making it the authority's most heavily subsidized facility.

No regularly scheduled buses use the Wabash Tunnel, although they did for three recent weeks as a detour during rail rehabilitation work that partly closed the nearby Mount Washington Transit Tunnel.

Consultants who planned conversion of the Wabash Tunnel had predicted it would attract 4,500 vehicles a day by 2015.

If the full Port Authority board concurs with the committee recommendation at tomorrow's monthly meeting, the contract extension with Bruce & Merrilees will go into effect Jan. 13.

The board is expected to agree to a one-year contract extension with Parking Solutions Inc. to run the 150-space parking lot on a small plateau between the north end of the tunnel and West Carson Street. The authority would be paid $8,750 a month, or $250 more than the current contract.

Meanwhile, the number of hours that the Wabash is restricted to HOVs was reduced while the number of hours available to solo motorists was increased, effective yesterday.

Here's the new schedule:

Inbound -- 6 to 9 a.m. weekdays, HOV only; 9 a.m. to 2 p.m., unrestricted traffic.

Outbound -- 3 to 6 p.m. weekdays, HOV only; 6 p.m. to 5 a.m., unrestricted traffic. Also, 6 p.m. Friday through 5 a.m. Monday, unrestricted traffic through the weekend.

Trucks are not permitted in the tunnel at any time.