According to several reports, FASTRACK seems to be more efficient than the normal weekend track work, since track workers can get a lot more done and not have to worry about any passenger subway trains (maybe one or two work trains). In addition, FASTRACK has been taking place where there is other subway service available. Example: In Midtown and Lower Manhattan there are a toal of 5 different lines (8th Ave IND, 7th Ave. IRT, 6th Ave IND, Broadway BMT and Lex. Ave. IRT). Therefore, if they shut one of them down for four nights straight, compared to 4 weekends in a row, IMHO, it is not a big deal.