PennDOT and Norfolk Southern Railway finalized an official agreement Friday to bring an additional round trip for passenger train service between Pittsburgh and New York City.

PennDOT officials said the state will invest more than $200 million for infrastructure and safety improvements that will help to accommodate the additional trains.

Amtrak now operates one daily round trip between Pittsburgh and New York City, via Harrisburg and Philadelphia. The agreement supports increasing that to two daily round trips. It would mark the first additional passenger train service for Western Pennsylvania in decades.

Separate federal funding is also providing new Airo trains on the route, which include new cabin interiors with panoramic windows, larger tray tables and upgraded chairs.

PennDOT Secretary Mike Carroll said the agreement will lay the groundwork for passenger rail expansion in the western part of the state, as well as preserving a heavy-traffic freight corridor.

“Ensuring more Pennsylvanians have access to safe and reliable transportation to Western Pennsylvania will reduce commute times, help connect hundreds of thousands of residents and boost local economies,” Carroll said.

Amtrak’s Pennsylvanian line runs through stations in Pittsburgh, Greensburg, Latrobe, Johnstown and Altoona before continuing to Harrisburg, Philadelphia and eventually New York City.

An eastbound Pennsylvanian train departs Pittsburgh once daily, at 7:30 a.m., and a westbound Pennsylvanian train arrives in Pittsburgh at 8 p.m. daily.

A feasibility report about adding a round trip said one possible schedule would have eastbound trains departing Pittsburgh at 7 a.m. and 12:30 p.m. daily and westbound trains arriving in Pittsburgh at 3 and 10 p.m. daily.

Norfolk Southern will complete the construction work, which should include upgraded rail lines, sidings and necessary communications signals infrastructure, according to PennDOT.

In addition to the $200 million in state funding, PennDOT said it has applied for grant money through the Federal Railroad Administration to help pay for the improvements.

The corridor is a main artery for double-stack intermodal traffic and is one of the busiest and fastest links on Norfolk Southern’s network, according to a release.

“This is a win-win agreement that would not be possible without the dedication and collaboration of our state officials, who share our vision for enhanced rail service across the Keystone State,” said Norfolk Southern Senior Chief Strategy Officer Mike McClellan.

In addition to another round trip for passenger service, the upgrades should improve the reliability of trains, but likely won’t improve speeds. The Pennsylvanian takes more than five hours to go between Pittsburgh and Harrisburg, and more than nine hours between Pittsburgh and New York City.

PennDOT Deputy Secretary Jennie Louwerse said last year that Western Pennsylvania’s mountainous terrain makes improving speeds extremely difficult and overly costly.

Ryan Deto is a Tribune-Review staff writer. You can contact Ryan by email at rdeto@triblive.com or via Twitter .