All is quiet in the nearly completed subway tunnels 66 feet below the surface of the Allegheny River.
That is not the case elsewhere along the 1.2 miles of the Port Authority's North Shore Connector project, where the din and controlled chaos of construction prevail.
The $538.8 million project to extend the Light Rail Transit system to PNC Park and Heinz Field is about half finished, and on schedule, said Winston Simmonds, Port Authority's rail operations/engineering officer.
The twin tunnels beneath the river and the shell of the underground station next to the baseball stadium are 97 percent structurally complete and await finishing work including tracks, signals and lighting.
A huge excavation has been opened adjacent to the Gateway Center subway station, which was closed Oct. 31 to make way for construction of a new station. Workers are building what amounts to a giant concrete box to enclose the underground station and tracks. The work also caused long-term closure of the Stanwix Street-Liberty Avenue intersection.
On the North Shore, overhead track is being erected along Reedsdale Street on the northern edge of Heinz Field. It will carry the system from PNC Park to an elevated station above Allegheny Avenue between the football stadium and the Rivers Casino.
The connector is scheduled to open sometime between December 2011 and the following March, Mr. Simmons said.
"When you're spending $500 million, it's hard for people to fathom," he said after a three-hour, end-to-end tour of the project last week. "But when you come down here and see it, it gives you a sense of appreciation of the size and magnitude of the challenges. In 1.2 miles we've packed in a lot of different construction elements and construction techniques."
The old station has been boarded shut, with rail service ending at Wood Street for the next two years. The decorative lighting and multicolored ceiling panels have been torn out and replaced with construction lighting.
Over the coming month, workers will painstakingly remove the ceramic Romare Bearden mural, tile by tile. It will be restored and displayed in the new station. The single tile that was installed upside down will remain that way, Mr. Simmonds said.
Original plans called for Gateway Center to stay open during construction. By closing it, the authority will save $4 million to $5 million. Giving the contractor unfettered access to the site will help the project stay on schedule, Mr. Simmonds said.
The foundation and walls of the new Gateway Center station are taking shape in a sprawling, 60-foot-deep hole in the block between Penn and Liberty avenues.
Working from the mouths of the new river tunnels toward the existing subway, the contractor has shored the sides of the excavation, poured the concrete foundation and is preparing to start erecting the 4-foot-thick, concrete outer walls of the station.
More than a dozen huge steel struts, painted white, are wedged across the hole to keep the sides from caving in until the concrete walls are finished.
The new station will have a center platform (like those at Mt. Lebanon and Castle Shannon) and a glass atrium that will allow natural light to flow in and give passengers a worm's-eye view of the skyscrapers towering above it.
The station structure is being built for $48.8 million by North Shore Constructors II, a joint venture of California-based Obayashi Corp. and West Mifflin-based Trumbull Corp. The combo also has the $156.5 million contract for the tunnels and PNC Park station shell.
Riders have seen the last of the old Gateway station and its loop. The subway line will make a sharp right turn in the area where the current loop begins. That will take it into the new Gateway station and then on to the North Shore.
"The loop is obsolete," Mr. Simmonds said. The old station will be converted to fan and equipment rooms.
The mouths of the 2,240-foot-long twin Allegheny River tunnels sit in the shadow of the old Horne's building, below where the traditional tree soon will sparkle.
The outbound tunnel descends from Gateway Center at a fairly steep 6 percent to 7 percent grade, similar to the slope of the Mount Washington Transit Tunnel, and snakes to the left. "If we didn't [turn left] we'd end up at home plate of PNC Park," Mr. Simmonds said.
The tunnel continues down for nearly half of its length, bottoming out about 66 feet below the surface of the river. The track flattens briefly, then begins to ascend, curving right and then left to reach the first North Shore station aside PNC Park.
The tunnel is actually a series of4-foot concrete circles, 22 feet in diameter, that were bolted in place as a 500-ton boring machine carved its way through the earth starting in January 2008.
The tunnel connects to the PNC Park station after a sharp left turn. The interior structure of the underground station, which also will have a single center platform, is nearly complete.
After that, the light-rail extension climbs quickly to an 1,800-foot elevated stretch of track that is taking shape along Reedsdale Street next to Heinz Field. Thirteen connected spans made of concrete and steel will carry the trains to a station that will be built above Allegheny Avenue.
Crews last week were pouring concrete for the deck of the sixth of the 13 spans, covering it with wet burlap to help it cure properly. Below them, others were painting the steel superstructure of the elevated line, which will be royal blue.
Trains leaving PNC Park will climb a 7 percent grade to the elevated track, Mr. Simmonds said. The steepest grade in the light-rail system is 10 percent on the Allentown line, he said.
Heinz Field will be the end of the line for the foreseeable future. Trains will reverse direction on a "track tail" that will be built beyond the last station. It also can be used to stage several trains to await departing stadium crowds.
The $39.7 million contract for aerial guideway and the elevated station went to Brayman Construction Corp., of Saxonburg.
Mr. Simmonds said the first two years of construction on the North Shore Connector have been free of major problems.
"Since we're coming out of the ground now, a lot of the risk has been eliminated. A lot of the risk is in the underground construction," he said.
The project still faces a funding gap, but that has shrunk significantly since January, when it was $117.8 million. The authority got $62 million in federal economic stimulus funding and trimmed the estimated project cost by another $14 million, leaving about $42 million unfinanced.
Mr. Simmons said the authority is working to secure additional federal funding, and the project is not in imminent danger.
Jon Schmitz can be reached at email@example.com or 412-263-1868.