It was a frustrating start to the week for thousands of LIRR commuters due to delays caused by bridge work lasting longer than scheduled, as well as signal trouble.

Ongoing work to replace a 66-year-old bridge on Cherry Lane Bridge in Carle Place was blamed for the cancellation of several Penn Station-bound trains Monday morning.

Trains on the Ronkonkoma and Port Jefferson branches were impacted.

The work was scheduled to wrap up Sunday, but work was still being done Monday.

Signal trouble at Jamaica station Monday also caused up to 45-minute delays on westbound trains.