Not only that it needs a route to run on, which would either be the Hammersmith and City/Circle Line, District Line or Metropolitan Line, though think the latter uses S8 stock.
Suggest you search for one of the many threads in this forum suggesting whichever line you want to drive the S7 Stock on, and add your support to that thread, rather than post a meaningless "I want this train" thread without details.
Agreed, you're not going to get the S7 without a line. The tiny bit of the H&C/Circle on the GWE remaster isn't enough to justify all the work that goes into building multiple units. And I'd suggest you're very unlikely to get all of the District Line given its size and complex timetable, as much as I and a few others would love it.
Metropolitan line always felt to me the best way to get S Stock in game. Very regularly requested on here.
