The River Line, the five-year-old Camden-to-Trenton light-rail route, is growing up.

By the end of this year, ground is supposed to be broken for a $40 million station in Pennsauken to link the River Line with the Atlantic City Line. That will open the way for easier travel to 30th Street Station in Philadelphia, as well as to the Jersey Shore.

And the River Line is getting $24 million for an upgraded signal system that will allow for more frequent service and improved safety.

"Ridership on the River Line has grown significantly, and we've really maxed out the infrastructure," NJ Transit spokesman Dan Stessel said. The new signal system may allow NJ Transit to add one more express trip between Florence and Trenton, he said.

The upgrading of the signal system on the line will be a step toward "positive train control" that can automatically apply the brakes if an engineer misses a stop signal. Such systems were required by federal legislation passed a month after a deadly train collision killed 25 people near Los Angeles in September.

Positive train control, which must be in use by 2015, may allow the River Line to overcome one of its biggest obstacles to greater ridership: providing later service.

Now, weekday passenger service has to end by 10 p.m., because the River Line shares tracks with Conrail, which operates freight service between 10 p.m. and 6 a.m. With federal approval and with positive train control to prevent conflicts between freight and passenger trains, the River Line might operate trains concurrently with Conrail, Stessel said.

The River Line's new Pennsauken station is one of the few new transportation construction projects in the Philadelphia region to come out of the recent federal stimulus funding.

"It's exciting," said Bob Cummings, Pennsauken township administrator. "For people who live here and work in the city, this is an opportunity to go directly to 30th Street. And you could jump on the train here to head to Atlantic City."

The two-level station is to be built where the Atlantic City Line passes over the River Line, just south of Derousse Avenue and west of River Road, in the shadow of the Betsy Ross Bridge. Precise details of its location and design have not been determined.

Federal stimulus money has elevated the project quickly from a planner's dream to a town's reality.

The Delaware Valley Regional Planning Commission on Feb. 26 approved the project for stimulus money, making it one of the few new projects funded in the region. Most transportation stimulus money was earmarked for highway and bridge repairs and upgrades, rather than for new construction.

Because the Atlantic City Line is on an embankment above the River Line, the station will need upper and lower platforms with passenger elevators, Stessel said. The plans call for about 250 parking spaces near the station.

Construction is expected to take 21/2 to 3 years, Stessel said, so the station will probably be completed by late 2012.

The development should not affect neighbors, Cummings said.

In a recent meeting between Pennsauken and NJ Transit officials, Cummings said, "we underlined the importance of not doing anything that would be a nuisance to the nearby residents."

"The township is definitely supportive of the project at this stage," Cummings said. "We're looking forward to getting more details."

Stessel said NJ Transit officials would go to Pennsauken to outline details of the plan to residents and officials of the township "in the very near future."

Pennsauken already has two River Line stations, at 36th Street and Route 73.

The light-rail River Line, which opened in 2004, links Camden and Trenton, with 15 stops in Delaware River towns between the two cities.

The Atlantic City Line operates between 30th Street Station and Atlantic City, with stops in Cherry Hill, Lindenwold, Atco, Hammonton, Egg Harbor City, and Absecon.

Ridership on both lines has been growing since 2004, although the Atlantic City Line's decreased slightly last year as casinos lost business because of increased competition and the sour economy.

The River Line now carries more than 9,000 passengers per weekday, up from 4,200 weekday passengers in 2004.

The Atlantic City Line carried 3,500 weekday passengers last year, up from 3,050 a day in 2004, but down from 3,600 in 2007.

Contact staff writer Paul Nussbaum at 215-854-4587 or pnussbaum@phillynews.com.