Of the four line cuts being mentioned, all are overlapping ones - that is the parts that would be cut go along the route of another line. One is a local that doesn't run nights or weekends, presumably the parallel express would now run local all the way - a major pain for those living way out in Queens. One is a skip-stop rush hour service - i.e. the two lines each do alternate stops to make for faster travel, one is useful since it reaches large chunks of South Brooklyn from the Financial District, while it's overlapping line turns off into Brooklyn a bit further north, the third one is the only line not to touch Manhattan, and as such has long been the stepchild of the system, but it is very useful for getting around between points within Brooklyn or from Brooklyn to Queens. The part which they want to shut down runs within Queens and isn't that big a deal - it already only runs nights and weekends.