Construction has officially started on the four stations on the Metro-North Waterbury Branch Line.

Stations getting upgrades includes Derby-Shelton, Ansonia, Beacon Falls and Seymour stations.

The rail service on the line will be temporarily replaced with bus service from July 20 this year until May 31 next year.

Gov. Ned Lamont's office says some of the construction can't be done safely while trains are running. Construction is set to finish by spring 2028.