The Metropolitan Transportation Authority's Metro-North Railroad began changing its timetables on Monday to accommodate a major, multi-year Connecticut Department of Transportation (CTDOT) catenary and bridge improvement project on the New Haven Line.

The work involves the replacement of the 100-year-old overhead catenary wires that supply power to trains as well as the reconstruction of five rail bridges in this critical section of the New Haven Line.

The schedule change will affect most peak-hour trains on the New Haven Line. As a result, many peak-hour New Haven Line trains (including some modification to Shore Line East trains) will operate up to six minutes earlier or up to 14 minutes later. Also, station stops made by some trains will change.

There will also be track outages that will require passengers to board trains from temporary platforms and, occasionally, from opposite-side platforms.

Metro-North and CTDOT worked together in an effort to limit the project's impacts on providing reliable train service.

The improvements to the catenary system, bridges and signals will ultimately result in a more reliable service, according to Metro-North and CTDOT.