Amtrak is planning to roll out new service on its much-maligned and often-delayed Acela route this July, providing nonstop service between New York and Philadelphia for the first time. The new route would also provide nonstop service to Washington from Philadelphia.

Cutting three New Jersey stops from the trip and shaving down commute times between New York and Philadelphia to about an hour could help solidify the “sixth borough” status of the City of Brotherly Love, real estate brokers and developers said.

About 1.5 million passengers a year use Amtrak to commute between New York and Philadelphia on a regular basis, and the number is growing, particularly among people in their 20s and 30s seeking more affordable housing, real estate brokers said. Amtrak expects the new line to boost its business clientele, a spokesman said.

“After 9/11, we had an influx of people coming down here from New York,” a partner in the Philadelphia-based development firm Miles & Generalis Inc., Thomas Miles, said. “Today, there is tremendous development going on around the train station.”

Two high-end condominiums with about 200 residential units each are under construction within walking distance of Amtrak’s 30th Street Station in Philadelphia.

The next frontier for development in that city, according to developers, is across the Schuylkill River from the station, still within walking distance to the train. Residential units there are selling for about $400 a square foot, compared with an average of more than $1,000 a square foot in Manhattan. Residential real estate in Philadelphia has yet to exceed that threshhold, even in fashionable neighborhoods such as historic Society Hill and Rittenhouse Square.

“We have a price point that we won’t get past at this point, and in New York there doesn’t seem to be any limits,” another partner at the firm Miles & Generalis Inc., Mr. Generalis said.

Easing the commute between New York and Philadelphia could push Philadelphia’s prices higher.

Architect Richard Meier in 2005 designed plans for a 44-story residential glass tower near Philadelphia’s train station, with apartments priced up to $5 million. “Those units were for a New York clientele and were in close proximity to the train station,” Mr. Generalis said. Construction of the building has been put on hold because the units did not attract enough attention from buyers. It could be revived, however, as Philadelphia continues to draw New Yorkers to its streets, local developers said.

“When you take the commute from an hour and a half to about an hour, it will make people in New York who were on the fence consider living in ‘the sixth borough,'” a senior vice president at Coldwell Banker Preferred, David Krieger, said.

Some transportation professionals said Amtrak’s high fares are a stumbling block to the creation of a seamless commercial and residential partnership between New York and Philadelphia.

“Because the fares are so high, Amtrak is still not creating the connections we ought to have between the two cities,” the president of the Regional Plan Association, Robert Yaro, said in an interview yesterday.

Acela service between the two cities costs about $129 one way. A price tag has not yet been attached to the nonstop service, according to an Amtrak spokesman.

“Every other industrialized country has a high-speed rail system, creating synergy between cities and increasing the size of the marketplace to benefit both cities. We’re so far behind, it’s ridiculous,” Mr. Yaro said.

In 2006, 24 million passengers rode Amtrak, and more than 9.2 million came through New York’s Pennsylvania Station, a record for the railroad. “We feel that we’re competitive with the airline industry,” an Amtrak spokesman, Clifford Cole, said.