With three stations along 1.8 miles, a recent New York University-led study identified Phase 1 as the most expensive subway build in the world on a per-kilometer basis. Phase 1, which opened at the start of 2017 and earned an ENR Best of the Best nod for a transit project, cost $4.5 billion. The current cost estimate is up $558 million since MTA’s prior estimate in November 2019, which FTA officials say comes from an increase in unallocated contingency for project risks. Plans for Phase 2 of the Second Avenue subway project call for tunnel segments built in the 1970s to be adapted for use.

The scope of the third contract would include cut and cover construction of the 106th Street station structure and connections for two tunnel sections built as part of an incomplete 1970s project, plus station entrances and connections to two ancillary buildings, Gary says. That contract would also include restoration and conversion of an existing tunnel for the 116th Street station and cavern mining for the 125th Street station. According to Gary, the second Phase 2 contract will include tunnel boring machine construction between 115th and 125th streets, and west along 125th to a point between Malcolm X Boulevard and Adam Clayton Powell Jr. MTA also says it expects to solicit a design-build contract for tunnel boring and cavern work sometime this year. MTA says it plans to solicit that work within the next few months, with a cost estimated between $25 million and $100 million. The first contract would cover early works and utility relocation, records show. Construction of this phase would be broken up into four contracts, he says. Gary, speaking at an eminent domain public hearing March 15, outlined MTA’s plan for this piece of the project.

New york city subway lines