Elevators for two PATCO train stations have been delayed by construction problems and the discovery of the remnants of an abandoned, century-old subway station during excavation work.

The elevators were supposed to be ready for use by the end of 2012 at PATCO's Ninth-10th and Locust Street subway station in Center City and the elevated Ferry Avenue station in Camden.

But the $5 million project has been slowed by permitting delays, supplier problems, utility conflicts, and, most important, the discovery of the old station under the Ninth and Locust site.

PATCO engineers delayed work while they unearthed the history of the earlier construction. They concluded that the remnants of the old station were not historically significant enough to preserve.

The old station was part of the never-finished Locust Street Subway and was apparently built between 1916 and 1918, PATCO spokesman Tim Ireland said.

In the 1930s, the station was demolished during construction of part of a Center City subway loop that was never completed, Ireland said.

However, the north wall was only partially demolished, and that is what crews encountered last year as they excavated for the PATCO elevators. The current crews finished the demolition begun by their Depression-era counterparts.

At Ninth-10th and Locust, two elevators are being installed. One, from the street level to the concourse, is scheduled to be fully installed by April, and the second, from the concourse to the platform level, is to be finished by June, Ireland said.

The Ferry Avenue elevator is now supposed to be installed by April.

A.P. Construction of Blackwood was awarded a $4.5 million contract for the work in October 2011, along with a $500,000 contract to Burns Group of Philadelphia to monitor construction.

The Federal Transit Administration is providing about $3.5 million of the cost for the elevators in Philadelphia and Camden.

With the addition of the elevators, seven of PATCO's 13 stations will be accessible to handicapped passengers.

The other stations with elevators: 15th-16th and Locust Street, Eighth and Market Street, Broadway, Woodcrest, and Lindenwold.

Contact Paul Nussbaum

at 215-854-4587 or pnussbaum@phillynews.com.