A new Ohio-Kentucky-Indiana Regional Council of Governments (OKI) study looking at the future use of the City's subway tunnels was presented to the OKI Intermodal Coodinating Committee on September 9.
The Cincinnati Subway Conversion Study, conducted by URS Corporation, looks at three possible options: maintaining the tunnels, filling them, or improving them for light rail transit.
Focusing on the largest segment of tunnels that exist - from Walnut Street to the portals located north of the Western Hills Viaduct and including the underground stations at Race Street, Liberty Street, and Brighton - the study asks five basic questions:
- What is the physical condition of the tunnels?
- What repairs are recommended to preserve the tunnels?
- Is it feasible to operate light rail transit within the tunnels, and to use the existing station areas?
- If it is feasible to operate light rail, what modifications will have to be made to the tunnels and what would be the cost?
- What is the current value of the tunnels for consideration of a potential local funding match?
Water and the damage done
A 2006 inspection showed that the overall condition of the tunnels is fair to good, but ten locations show signs of advanced deterioration, mostly caused by water leakage at construction joints.
The deterioration is most severe in the segment from Linn Street to the Brighton station.
The Race Street and Liberty Street stations were found to be in generally good condition, and the Brighton station was in fair condition with deterioration to the roof slab and beams.
Immediate maintenance recommendations are estimated at $3 million and would include:
- Replacement of vent grates south of Liberty Street
- Repair of the vent openings north of the Brighton station
- Repair of floor drains
- Repair sewage leaks
- Replace tunnel joints at ten locations
- Yearly inspections
One future option, filling the tunnels with controlled density fill, would cost an estimated $20 million.
Another $15 million would be required to relocate the existing water main and communication lines within the tunnels before filling could begin.
Light rail option?
The study finds that, with a few modifications, light rail transit in the tunnels is feasible and would cost $115 million.
Of that $115 million, $85 million would be dedicated to hard construction costs, $15 million to soft costs, and $15 million for water main and communications line relocation.
New platforms and headhouses would be required for all three stations, as well as new construction for ticketing and other related transit functions.
Utilizing original construction contracts and maintenance recommendations, the study found that the current net value of the tunnels is between $30 million and $40 million.
In proceeding with the protection of this City asset, the study recommends:
- Maintaining the tunnels in the near-term and develop a funding strategy any long-term decision
- Planning for the relocation of the water main and communication lines
- Continuing documentation for a potential local funding match
- Studying future light rail transit impacts to the CBD street grid and the feasibility of extending the tunnel system along the I-71 corridor and down Walnut Street, past the Riverfront Transit Center, and into Covington
- Studying the possibility of running light rail along Central Parkway