The Atlantic City Railroad was a Philadelphia and Reading Railway subsidiary that was formed on April 1, 1889 to consolidate the company's southern New Jersey lines:
- Camden, Gloucester & Mt. Ephraim Railway
- Philadelphia and Atlantic City Railway
- Williamstown Railroad
- Williamstown and Delaware River Railroad
The Atlantic City Railroad later acquired, controlled or leased the following lines:
- Camden County Railroad
- Cape May, Delaware Bay and Sewell's Point Railroad
- Ocean City Railroad
- Seacoast Railroad
- Stone Harbor Railroad
- Wildwood and Delaware Bay Short Line Railroad
- Pleasantville & Ocean City Railroad
- Brigantine Railroads
On November 2, 1932, the Pennsylvania Railroad and Reading Company joined their southern New Jersey railroad lines into one company, The Pennsylvania-Reading Seashore Lines which the Pennsylvania Railroad had a 2/3 ownership, and the Reading Company had a 1/3 ownership.
On July 15, 1933, the Atlantic City Railroad leased the West Jersey & Seashore Railroad and changed its name to Pennsylvania-Reading Seashore Lines.