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The most expensive subway ever built

Phase 1 of the Second Avenue Subway cost $4.6 billion to build 2.7 kilometers of tunnel and three stations. At roughly $1.7 billion per kilometer, it is the most expensive subway ever constructed — five to twenty times the cost of comparable projects in Europe. Here's how it happened.

New York City Second Avenue Subway, Phase 1 · MTA
$4.6B Total cost
$1.7B/km Cost per kilometer
2.7km New tunnel built
10 years Construction time
18 years From proposal to opening
Madrid Plan de Ampliación · Metro de Madrid
~$2.8B Total cost
$50M/km Cost per kilometer
56km New tunnel built
3 years Construction time
4 years From proposal to opening

Two timelines

New York spent 10 years and $4.6 billion building 2.7km. Madrid built 56km in 3 years for $2.8 billion.

New York City Second Avenue Subway, Phase 1 · MTA
2.7km · $4.6B · 10 years construction
1919

First proposed

A Second Avenue line is included in early city plans for subway expansion.

1929

Formally planned

Included in the IND Second System — a massive expansion that will never be built.

1972

Construction briefly starts

Ground is broken in three locations. Work halts almost immediately as the city's finances collapse.

1975

Fiscal crisis kills the project

New York City's near-bankruptcy puts the subway on ice for a generation.

1999

Planning restarts

A new environmental review begins — 80 years after the line was first proposed.

2007

Construction begins

Phase 1 (96th to 63rd Street) finally breaks ground. Budget: $3.8 billion.

2014

Original opening target

The project was supposed to be done. It was not. Budget has grown to $4.5 billion.

2016

Emergency acceleration

Governor Cuomo personally intervenes, paying contractors $66M in overtime to force completion.

Jan 2017

Phase 1 opens

Three new stations open at 72nd, 86th, and 96th Streets — 98 years after first proposal. Final cost: $4.6 billion.

Madrid Plan de Ampliación · Metro de Madrid
56km · ~$2.8B · 3 years construction
1994

Expansion commissioned

The Madrid regional government commissions a plan to dramatically expand the metro system.

1995

Construction begins

Work starts simultaneously on 40km of new lines and 37 stations. Budget: ~$1.7 billion.

1998

First phase opens

40km of new track and 37 stations open — just three years after construction began.

1999

Airport extension opens

A 12km extension to Barajas Airport is completed.

2003

MetroSur opens

A 41km circular line connecting five southern suburbs opens. Total expansion: ~56km.

Cost per kilometer

How New York compares to other major transit projects (2020 dollars).

New York (2nd Ave)
$1,700M/km
London (Crossrail) *
$700M/km
Paris (Grand Paris Express)
$270M/km
Istanbul (M5)
$80M/km
Madrid †
$50M/km
Seoul (Line 9)
$43M/km

All figures in 2020 USD. * Crossrail includes mainline rail infrastructure and is not a direct metro comparison. † Madrid figures include ~18.5km of above-ground track, which lowers the per-km average.

Why did it cost so much and take so long?

Four structural problems identified by the Transit Costs Project at NYU Marron Institute.

77% of construction costs

Bloated station design

Stations account for the vast majority of Phase 1's cost. NYC's station boxes are 150–260% larger than the actual passenger space — with enormous back-of-house rooms demanded by different MTA departments. Madrid's stations had virtually no excess space.

40–60% of hard costs

Labor costs & staffing

Labor in NYC consumes twice the share of construction costs as in Europe (19–31%). A tunnel boring machine that requires 30 workers in Istanbul required 46 in NYC. A launch box that took one year to build in Madrid took three years here.

$452M in design fees

Consultant overload

The MTA gutted its in-house engineering capacity over decades, replacing staff with expensive outside consultants. The design contract alone grew from $187M to $452M. Internationally, soft costs run 5–10% of construction; in NYC they hit 21%.

Only 2 bids on tunneling

Procurement failures

Unusual risk allocation — MTA placed geological risk on contractors instead of absorbing it — drove away bidders and inflated prices. The main tunneling contract received only two bids. Contractors hedged uncertainty by pricing in 15–40% contingencies.

What can we do about it?

Essays on what needs to change — and how.