The Tappan Zee Bridge demolition is set to impact Hudson Line train service this weekend.

Those riding the rails from around midnight Friday until 7 a.m. Saturday should expect half-hour delays and bus service in place of trains between Yonkers and Tarrytown stations as crews remove sections of steel from the old bridge over the tracks.

The removal follows , which saw the massive Left Coast Lifter used to remove a 235-foot-long section of steel near the Westchester County shore, the first of 20 which will see the 61-year-old bridge stripped down.

Similarly, the Left Coast Lifter will be used overnight Friday.

Metro North Railroad trips to Tarrytown and stations north of it will necessitate getting off at Yonkers and onto an express bus to Tarrytown, where train service will resume. For stations between Yonkers and Tarrytown, local train service will be provided as far as Irvington.

Passengers headed from Glenwood, Greystone, Hastings, Dobbs Ferry and Ardsley to Tarrytown and points north will have to take a local train to Irvington, a bus to Tarrytown, then get back on the train.

Southbound trains will only run to Tarrytown, with passengers having to take an express bus to Yonkers. Those headed to Ardsley, Dobbs Ferry, Hastings, Greystone and Glenwood stations will take a bus to Irvington, where train service will be provided.

This is not the first instance of bridge construction affecting Metro-North service: Back in 2015, girder installation on the new bridge created .

Demolition is scheduled to take roughly a year. The new bridge should be completed some time in 2018, though the state Thruway Authority has not given a concrete date on when it would be finished.