This story is interesting. The subway tunnel that connects the R train to Manhattan was badly damaged during Hurricane Sandy. After 2 months of emergency repairs, service was restored.
However, most of the equipment was damaged by the storm. There are signal problems and track switch failures, at a rate 10x more compared to before Hurricane Sandy.
The NYC MTA has two choices for repairs. They can close the tunnel nights and weekends, and do the repairs a little at a time. Or, they can shut down service completely and do repairs 24×7. With partial service closures, it would take 38 months to complete repairs. With a full service shutdown, it would take 14 months to complete repairs.
Going with the 14 month closure, the tube would be available for construction 24/7. There are several reasons why the shorter duration is favorable, including but not limited to the fact that Federal funding has been allocated to NYC Transit to repair damage sustained by the storm and it is required that work paid for with federal funding be completed within 24 months of the project’s start.
The Federal government gave the NYC MTA money for the repairs, PROVIDED work is finished within 24 months. That forces the MTA to shut down service completely, rather than doing repairs during off-peak hours. In effect, the Federal government forced the MTA to inconvenience commuters for 14 months with no service at all.