Long Ridge Road will be closed at 10 a.m. on Friday and is expected to re-open by 4 p.m. on Wednesday.
Motorists will have to follow detour signs to work around the construction.
There will also be no Metro-North service between Danbury and Norwalk. Alternate bus service will be provided with train service restored by Monday.
There will be an increase in noise levels in the vicinity of the railroad crossing due to the construction.
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