The Long Island Rail Road’s Main Line went down for almost an hour Friday afternoon, causing massive delays that are expected to last into the commute.

Service was suspended on the Huntington, Port Jefferson, Ronkonkoma and Oyster Bay branches of the commuter railroad, which account for the bulk of the LIRR’s daily ridership of more than 300,000 people.

The first commuter trains were canceled at 4:09 p.m., records show.

MTA spokeswoman Meredith Daniels said “switch trouble” in Nassau County caused the interruption and was fixed around 5 p.m.

However, it will take longer for service to be fully restored, she added.

Paul Koptka, 42, of Huntington, grabbed a beer as he spent more than an hour waiting at Penn Station before finally hopping on the 5:46 p.m. Huntington train.

“It’s super disruptive, is what it is,” he said.”It gets old. There are thousands of people here whose Fridays are being screwed with because the railroad can’t get their act together.”