In the 1920s, the Lehigh Valley Railroad still had regularly scheduled passenger service between Easton, PA and New York City - including their signature "Black Diamond Express" whose only intermediate stop was at South Plainfield.
Hillsborough commuters had a choice of two station stops for boarding - Flagtown or South Somerville (previously named Royce Valley) - and you had to be on time because there was only one train each morning that stopped at these stations.
The train left Flagtown at 7:00 AM and South Somerville at 7:06, and arrived in New York at 8:43. The return trip in the evening was 3 minutes faster as the 5:22 PM train got into Flagtown at 7:02 PM.
Check out this schedule from 1923!