To have some kind of understanding of how the Central Railroad of New Jersey evolved into what it had billed itself as The Biggest Little Railroad, the family tree of the companies that went into forming the CNJ would not be a bad place to start. The first two of these companies were the Elizabeth and Somerville and Somerville and Easton railroads, which merged together in 1849 forming the Central Railroad of New Jersey, thus forming the core of a greater CNJ to come and the nucleus of what would be the railroad's CENTRAL DIVISION. This stretched roughly 80 miles from Jersey City, NJ to Phillipsburg. The family tree of the CNJ consists of the following companies:

 

1.South Branch Railroad

2.Newark and New York Railroad

3.Manufacturers Railroad

4.Peth Amboy and Elizabeth Railroad

5.Constables Hook Railroad

6.Lafayette Railroad

7.Sound Shore Railroad

8.New Jersey Terminal Railroad

9.Bayshore Connecting Railroad

10.Raritan North Shore Railroad

11.High Bridge Railroad

12. Middle Valley Railroad

13.Longwood Valley Railroad

14.German Valley Railroad

15.Dover and Rockaway Railroad

16.Hibernia Mine Railroad

17.Ogden Mine Railroad

18.Lake Hopatcong Railroad

 

The last six of these evolved into the Wharton and Northern and Mount Hope Mineral Railroads, which although shown in CNJ employee timetables as such,were an integral part of their parent railroad and operated as such. West of the Delaware River, the Lehigh and Susquehanna Railroad became part of the CNJ and formed the Central Railroad of Pennsylvania, under which name it was operated primarily for tax purposes. It extended from Phillipsburg,NJ to Scranton, PA and constituted CNJ's Pennsylvania Division. It ran closely parallel to the Lehigh Valley Railroad for a considerable distance west of Easton,PA.