Firefighters were battling a large brush fire off Route 1 in Milford on Monday evening.
The fire broke out around 6:30 p.m. near the railroad tracks by Schoolhouse Road and firefighters are still dealing with hotspots on Tuesday morning.
Fire companies from Stratford were called in to help Milford firefighters try and contain the flames.
The fire forced Metro North to suspend service around 7 p.m. and Amtrak to delay all service from New York to New Haven.
Witnesses reported seeing thick black smoke from Interstate 95.