Not sure exactly what you are referring to here. The entire railroad industry has been consolidating into a handfull of very large carriers for decades. In the area you're refrring to Norfolk Southern and CSX predominate, but in a few areas, particularly in New Jersey, Conrail continues to operate some trackage under a provision called "shared assets"
In the years when railroading was the dominant form of transportation, the two major roads which pretty much limited themselves to the area you have in mind were the New Haven and the Jersey Central; both fell upon hard times after World War II and ended up in Conrail.
You could also look into a short line operating in this region, such as Raritan River or Morristown and Erie, or one of the small companies that was spun off from Conrail, such as Providence and Worcester. Or one of the small lines which operated on the waterfont in New York Harbor (Bush Terminal and Brooklyn Eastern District Terminal, for example). The possibilities are endless.
And since you're modeling, you also have the option of using your imagination and creating something that might have come about in this region if history had played out a little differently. It's gonna be your pike, and you have the right to follow any script you'ld care to.
What a revoltin' development this is! (William Bendix)