The 7 line — to so-called subway to nowhere — is set to cost the city of New York $2.1 billion for one additional stop and perhaps the shell of a second. On Monday, the costs are going to go up by a bit when the board approves a $10 million increase in design costs. While the cost of this early work has already tripled to $124 million from its original estimated price tag a few years ago, the MTA is still on the hook for $0, and the Mayor’s Office has built the overruns into its budget for the project. “It’s not out of the ordinary, it’s covered and this will cost the MTA $0,” Andrew Brent, a Bloomberg administration spokesman, said to amNY’s Urbanite blog. Now if only they could solve that problem of the omitted stop at 41st St. and 10th Ave.