Appendix A

Amtrak Gateway Project – Hudson Yards Study Final Report

by Tutor Perini Corporation and Parsons Brinckerhoff (2012)
Amtrak Gateway Project – 

Hudson Yards Study 

FINAL REPORT 

November 16, 2012

Prepared for Related Companies and Amtrak
Amtrak Gateway Project – Hudson Yards Study Final Report

 i November 16, 2012

Table of Contents 

1.0 EXECUTIVE SUMMARY ................................................................................................... 1-1

2.0 STUDY APPROACH AND SYNOPSIS ............................................................................. 2-1

2.1 Study Approach ............................................................................................................ 2-1

2.2 Study Synopsis ............................................................................................................. 2-1

3.0 AMTRAK’S GATEWAY PROJECT .................................................................................. 3-1

3.1 Overview of Gateway Project ....................................................................................... 3-1

3.2 Review of Internal Space Requirements for Tunnel ..................................................... 3-1

4.0 SITE LOGISTICS WITHIN THE HUDSON YARDS .......................................................... 4-1

5.0 UTILITIES .......................................................................................................................... 5-1

5.1 General ......................................................................................................................... 5-1

5.2 Storm & Sanitary Sewer ............................................................................................... 5-1

5.3 Electrical – AC & DC Power ......................................................................................... 5-2

5.4 Signal and Communication ........................................................................................... 5-3

5.5 Water (Fire & Potable) and Gas ................................................................................... 5-4

6.0 DESIGN SOLUTIONS & CONSTRUCTION OPTIONS .................................................... 6-1

6.1 Subdivision of Site ........................................................................................................ 6-1

6.2 Conceptual Design Alternates ...................................................................................... 6-1

6.3 Construction Options .................................................................................................... 6-3

6.4 Alternative 1: Fully Integrated Tunnel and Overbuild Foundation Structures ............... 6-5

6.5 Alternative 2: Fully Isolated Tunnel and Overbuild Foundation Structures .................. 6-6

6.6 Design Alternative 3: Partially Isolated Tunnel and Overbuild Foundations ................ 6-8

6.7 Option 3 (Not to Preclude): Future Tunnel Construction Methods ............................... 6-9

6.8 Summary of Construction Solutions for Pricing .......................................................... 6-11

7.0 COST ESTIMATES AND CONSTRUCTION SCHEDULES.............................................7-1

7.1 Cost Estimates .............................................................................................................. 7-1

7.2 Construction Schedules ................................................................................................ 7-1

8.0 CONCLUSIONS & RECOMMENDATIONS ...................................................................... 8-1

APPENDIX 

Engineering Drawings 
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Figures 

Figure 2-1: Section Reference Plan ...................................................................................... 2-2

Figure 2-2: Conceptual Design Solutions for the Gateway Tunnel ....................................... 2-5

SK-RP-01: Reference Plan for Pricing Solutions .................................................................. 2-6

SK-CS-01: Pricing Solution 1 – Fully Integrated Cut-and-Cover Tunnel .............................. 2-7

SK-CS-2A: Pricing Solution 2A – Deck with Full Depth Secant Piles (where practical) 

with No Center Overbuild Caisson ...................................................................... 2-8

SK-CS-02B: Pricing Solution 2B – Deck with Full Depth Secant Piles (where practical) 

with Center Overbuild Caisson ........................................................................... 2-9

SK-CS-02C: Pricing Solution 2C – Deck with Partial Depth Secant Piles with No 

Center Overbuild Caisson ................................................................................. 2-10

SK-RP-02: Reference Plan for Pricing Solution 3 Only ...................................................... 2-11

SK-CS-03: Pricing Solution 3 – Not To Preclude Future Tunnel Construction ................... 2-12

Figure 3-1: Tunnel Internal Space Requirements ................................................................. 3-2

Figure 4-1: Anticipated Work Zone and Access Route ......................................................... 4-2

Figure 6-1: Alternative 1: Fully Integrated Tunnel and Overbuild Foundation 

Structures ............................................................................................................ 6-2

Figure 6-2: Alternative 2: Fully Isolated Tunnel and Overbuild Foundation Structures ........ 6-2

Figure 6-3: Alternative 3: Partially Isolated Tunnel and Overbuild Foundation 

Structures ............................................................................................................ 6-3

Tables 

Table 2-1: Pricing Solutions ................................................................................................. 2-3

Table 2-2: Cost Estimates .................................................................................................... 2-4

Table 6-1: Tunnel Construction Options .............................................................................. 6-4

Table 6-2: Pricing Solutions ............................................................................................... 6-11

Table 7-1: Pricing Solutions .................................................................................................7-2

Table 7-2: Amtrak Tunnel Construction – Pricing Solution 1 ............................................... 7-3

Table 7-3: Amtrak Tunnel Construction – Pricing Solution #2A, 2B, and 2C ....................... 7-4

Table 7-4: Amtrak Tunnel Construction – Pricing Solution #3 ............................................. 7-5
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1.0 EXECUTIVE SUMMARY

The Northeast Corridor Infrastructure Master Plan, prepared by Amtrak and 

representatives of 12 northeastern states and released in spring 2010, projects a 

significant increase in both passenger ridership and Amtrak and NJ Transit train service 

across the Hudson River by the year 2030. The existing 100-year-old, two-track North 

River tunnels are at their current capacity of approximately 25 trains per hour (tph), per 

direction, and are insufficient to meet projected demand. 

Amtrak appointed Parsons Brinckerhoff (PB) to perform a preliminary evaluation related 

to adding two new tracks under the Hudson River as part of Amtrak’s Gateway Project. 

The new tracks would branch from the Northeast Corridor (NEC) tracks in New Jersey 

and run in tunnel into Penn Station New York (PSNY) via the ‘A’ Yard at the western limit 

of the station complex. The new tunnel tracks would connect to existing yard tracks and 

to an extension of the ‘I’ Ladder, providing, in total, access to existing platform Tracks 1–

18. This connection would be crucial to fulfill the operational reliability and capacity 

requirement that would serve as the backbone to Amtrak’s Gateway Project. 

The two new tracks would transverse under the southeast corner of the MTA-LIRR West 

Side Yards (Hudson Yards) which is currently under development by the Related 

Companies (‘Related’). Specifically, the new tracks would be located in tunnel(s) 

constructed under the southeastern section of the Eastern Rail Yard (ERY) Site between 

Eleventh and Tenth Avenues. 

Amtrak is aware that they should take advantage of establishing a right-of-way for the 

future Gateway Tunnel to make connections to ‘A’ Yard and the extension of the ‘I’ 

Ladder. Preliminary meetings between Related and Amtrak began in June of 2012 in 

which Related inquired if the proposed track alignment could be shifted farther north to 

avoid a proposed tower in the terra firma area just east of the Eleventh Avenue viaduct. 

Parsons Brinckerhoff revised the alignment with no significant operational impacts to the 

track geometry. This revised alignment provided less impact to the LIRR Maintenance 

Facility (MOE building). 

Amtrak, MTA-LIRR and Related understand that construction of both the Overbuild 

structures and the Gateway Tunnel should ideally occur during the same construction 

period in order to mitigate impacts to the railroad operations/facilities and the occupied 

new buildings in the future. Accordingly, Amtrak, MTA-LIRR and Related agreed to the 

appointment of Parsons Brinckerhoff and Related’s contractor, Tutor Perini Civil (TPC), 

to jointly undertake the study described in this report to develop and evaluate design and 

construction concepts for constructing the Gateway Tunnel in the Hudson Yards. 

Given that the potentially complex easement arrangements for the future Gateway 

Tunnel, LIRR facilities and Overbuild structures have yet to be resolved, three 

conceptual design solutions were developed for the Gateway Tunnel providing different 

levels of structural separation between the proposed tunnel and the foundations of the 
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 1-2 November 16, 2012

Overbuild structures. Furthermore, cognizant that the level of construction of the 

Gateway Tunnel will be dependent on the availability of funding, the study also 

developed construction options, which included constructing the Gateway Tunnel at the 

same time as the Overbuild Foundations, as well as options to construct the tunnel 

separately in the future. These included options to construct a deck structure above the 

elevation of the tunnel to facilitate future tunnel construction, as well as a ‘Not to 

Preclude’ option which entails reconfiguring the Overbuild foundations to preserve a 

pathway to construct the tunnel independently in the future. 

From the technical and cost evaluations of the various design and construction options 

considered, the study determined five ‘Pricing Solutions’ as providing the optimum cost 

and schedule comparisons for present day and future construction solutions for the 

Gateway Tunnel. All five Pricing Solutions require the section of tunnel under the LIRR 

MOE Building to be constructed during the same construction period as the Overbuild 

structures owing to the shallow depth of the tunnel in this area. The Pricing Solutions are 

presented below: 

Pricing 

Solution Description 

Current 

Construction 

Costs 

(See notes)

Future 

Construction 

Costs 

(See Notes)

Total 

Costs 

Complete 

First 

400 Ft 

Complete 

Last 

400 Ft 

1 Fully Integrated Cut & 

Cover Tunnel $120 $0 $120 4/2014 9/2014 

2A 

Fully Isolated With Deck, 

Full Depth Secant Piles, 

No Center Caisson 

$118 $93 $211 4/2014 7/2014 

2B 

Partially Isolated With 

Deck, Full Depth Secant 

Piles, Center Caisson 

$121 $101 $222 4/2014 7/2014 

2C 

Fully Isolated With Deck, 

Partial Depth Secant Piles, 

No Center Caisson 

$114 $94 $208 4/2014 7/2014 

3 

Fully Isolated, Not to 

Preclude, No Deck, 

Transfer Beams On 

Caissons, No Center 

Caisson 

$97 $133 $229 4/2014 7/2014 

Notes: 

1. All dollar values in millions 

2. Future costs based on 2012 dollars 

3. All pricing solutions include fully integrated cut/cover tunnel at Section C (Under MOE Building) 

Schedule 

1 Submit four (4) week study 11/16/2012 

2 NTP Design 12/3/2012 

3 Notice to vacate MOE 12/3/2012 

4 Vacating of MOE complete 3/1/2013 

5 Complete demolition of MOE & utility relocation 6/1/2013 

6 Start platform foundations 4/2014 

7 Start platform structural steel at Tower A 5/2014 
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2.0 STUDY APPROACH AND SYNOPSIS

2.1 Study Approach 

The following steps were implemented by the study: 

1. Evaluation of the Horizontal and Vertical Alignments of the Gateway Tunnel in the 

Hudson Yards. 

2. Evaluation of the Internal Space Requirements for the Gateway Tunnel. 

3. Evaluation of the Existing Infrastructure and Utilities in the Hudson Yards, Planned 

Overbuild Construction and Site Logistics. 

4. Subdivision of the Gateway Tunnel Alignment within the Hudson Yards based on the 

physical constraints determined in Step 3. 

5. Development of Conceptual Design Solutions (Alternatives) for the Gateway Tunnel 

based on different levels of structural separation with the Foundations of the 

Overbuild Structures. 

6. Development of Construction Options for the Conceptual Design Solutions based on 

constructing the Gateway Tunnel at the same time as the Overbuild Foundations or 

separately in the future. 

7. Technical Evaluation of a Matrix of the various Conceptual Design Solutions and 

Construction Options viable along the Gateway Tunnel Alignment within the Hudson 

Yards. 

8. Development of Plans and Sections for the Matrix items defined in Step 7. 

9. Development of Cost Solutions and Construction Schedules for most viable 

Construction Solutions for combining the Gateway Tunnel construction with the 

Overbuild Foundations or undertaking Tunnel construction separately in the future. 

2.2 Study Synopsis

The technical and cost evaluations of the various design solutions and construction 

options considered by the study are addressed in detail in subsequent sections of this 

report. Provided below is a synopsis of the study and its findings. 

Based on the existing infrastructure within the Hudson Yards and future Overbuild 

constraints, the Gateway Tunnel alignment was subdivided into four sections as 

illustrated in drawing SK-RP-1. The main characteristics of each section are summarized 

below: 
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Section A: The southwest end of the alignment, adjacent to Eleventh Avenue, is 

characterized by the high column loads imposed by the Overbuild 

Tower D (10,000 kip column loads). The tunnel alignment is also at its 

deepest in this section. 

Section AB: This section of the tunnel alignment is occupied by shop tracks 

serving the MOE Building and is characterized by multiple columns 

carrying the Overbuild platform only (2,000 kip loads). 

Section B: This section of tunnel is in close proximity to the existing Amtrak 

Empire Line Tunnel. This area is also characterized by multiple 

columns carrying high loads from Overbuild Structures (6,000 kip 

column loads). 

Section C: The western end of the tunnel is occupied by the LIRR MOE Buildings 

and is characterized by multiple high column loads from the Overbuild 

Structures (6,000 kip column loads). The tunnel is also at its 

shallowest along this section. 

Figure 2-1: Section Reference Plan 

Since the potentially complex easement arrangements for the future Gateway Tunnel, 

LIRR facilities and Overbuild structures have yet to be resolved. Three conceptual 

design solutions were developed for the Gateway Tunnel (Step 5 above). The design 

solutions, which are illustrated in Figure 2-2, provide different levels of structural 

separation between the proposed Gateway Tunnel and the foundations of the Overbuild 

structures. The Gateway track alignments beneath the Hudson Yards are the same for 

the fully integrated (Alternative 1) and fully isolated (Alternative 2) conceptual design 

solutions. However, the southern track would need to be shifted south approximately 

3 feet to accommodate the center Overbuild caissons shown for the partially isolated 

(Alternative 3) design solution (i.e., the middle caissons would be embedded in the 

center wall of the tunnel). 
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Cognizant that the level of construction of the Gateway Tunnel will be dependent on the 

availability of funding, the study developed construction options, which included 

constructing the Gateway Tunnel at the same time as the Overbuild Foundations, as well 

as options to construct the tunnel separately in the future (Step 6 above). The latter 

included options to construct a deck structure above the elevation of the tunnel 

concurrent with construction of the Overbuild foundations in order to facilitate future 

tunnel construction. In addition, a ‘Not to Preclude’ option was developed whereby the 

Overbuild foundations would be configured to preserve a pathway to construct the tunnel 

independently in the future. No other measures to facilitate future tunnel construction 

would be included with this option. 

Based on the technical and cost evaluations of the various design and construction 

permutations described above, the five ‘Pricing Solutions’ listed in Table 2-1 and 

illustrated in the drawings at the end of this section, were identified as providing the 

optimum cost and schedule comparisons for present day and future construction 

solutions for the Gateway Tunnel. However, the construction under the LIRR MOE 

Building (Section C) in all five Pricing Solutions requires the fully integrated tunnel 

(Alternative 1) to be constructed at the same time as the Overbuild construction 

activities. This is due to the shallow tunnel depth, which precludes constructing the 

sizable transfer beam required to carry the Overbuild column loads to either side of the 

Tunnel. 

Table 2-1: Pricing Solutions 

Pricing 

Solution Design and Construction Description Drawing 

1 Fully Integrated Cut-&-Cover Tunnel SK-CS-01

2A Deck with Full Depth Secant Piles (Where Applicable) – No Center 

Overbuild Caisson SK-CS-2A 

2B Deck with Full Depth Secant Piles (Where Applicable) – With Center 

Overbuild Caisson SK-CS-2B 

2C Deck with Partial Depth Secant Piles – No Center Overbuild Caisson SK-CS-2C 

3 Not to Preclude Future Tunnel Construction – No Center Overbuild 

Caisson SK-CS-03 

Cost estimates for the present day and future tunnel construction elements for each 

Pricing Solution are summarized in Table 2-2. 
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Table 2-2: Cost Estimates 

Pricing 

Solution Description 

Current 

Construction 

Costs 

(See notes)

Future 

Construction 

Costs 

(See Notes)

Total 

Costs 

Complete 

First 

400 Ft 

Complete 

Last 

400 Ft 

1 Fully Integrated Cut & 

Cover Tunnel $120 $0 $120 4/2014 9/2014 

2A 

Fully Isolated With Deck, 

Full Depth Secant Piles, 

No Center Caisson 

$118 $93 $211 4/2014 7/2014 

2B 

Partially Isolated With 

Deck, Full Depth Secant 

Piles, Center Caisson 

$121 $101 $222 4/2014 7/2014 

2C 

Fully Isolated Deck Lid, 

Partial Depth Secant Piles, 

No Center Caisson 

$114 $94 $208 4/2014 7/2014 

3 

Fully Isolated, Not to 

Preclude, No Deck, 

Transfer Beams On 

Caissons, No Center 

Caisson 

$97 $133 $229 4/2014 7/2014 

Notes: 

1. All dollar values in millions 

2. Future costs based on 2012 dollars 

3. All pricing solutions include fully integrated cut/cover tunnel at Section C (Under MOE Building) 

Schedule 

1 Submit four (4) week study 11/16/2012 

2 NTP Design 12/3/2012 

3 Notice to vacate MOE 12/3/2012 

4 Vacating of MOE complete 3/1/2013 

5 Complete demolition of MOE & utility relocation 6/1/2013 

6 Start platform foundations 4/2014 

7 Start platform structural steel at Tower A 5/2014 

 
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Figure 2-2: Conceptual Design Solutions for the Gateway Tunnel 

Alternative 1: Fully Integrated Tunnel and Overbuild Foundation Structures 

Alternative 2: Fully Isolated Tunnel and Overbuild Foundation Structures 

Alternative 3: Partially Isolated Tunnel and Overbuild Foundation 

Structures 

Overbuild Foundation Load (size & locations vary)

Overbuild Foundation Load (size & locations vary)

Isolation Casing for Caisson

Overbuild Foundation Load (size & locations vary)

Isolation Casing for Caisson
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SK-RP-01: Reference Plan for Pricing Solutions 
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SK-CS-01: Pricing Solution 1 – Fully Integrated Cut-and-Cover Tunnel 
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SK-CS-2A: Pricing Solution 2A – Deck with Full Depth Secant Piles (where practical) with No Center Overbuild Caisson 
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2-9 November 16, 2012

SK-CS-02B: Pricing Solution 2B – Deck with Full Depth Secant Piles (where practical) with Center Overbuild Caisson 
Amtrak Gateway Project – Hudson Yards Study Final Report

2-10 November 16, 2012

SK-CS-02C: Pricing Solution 2C – Deck with Partial Depth Secant Piles with No Center Overbuild Caisson 
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SK-RP-02: Reference Plan for Pricing Solution 3 Only 
Amtrak Gateway Project – Hudson Yards Study Final Report

2-12 November 16, 2012

SK-CS-03: Pricing Solution 3 – Not To Preclude Future Tunnel Construction 
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3.0 AMTRAK’S GATEWAY PROJECT

3.1 Overview of Gateway Project 

The Northeast Corridor Infrastructure Master Plan, prepared by Amtrak and 

representatives of 12 northeastern states and released in spring 2010, projects a 

significant increase in both passenger ridership and Amtrak and NJ Transit train service 

across the Hudson River by the year 2030. The existing 100-year-old, two-track North 

River tunnels are at their current capacity of approximately 25 trains per hour (tph), per 

direction, and are insufficient to meet projected demand. 

Amtrak requested Parsons Brinckerhoff (PB) perform a preliminary evaluation related to 

adding two new tracks under the Hudson River, from tracks along the Northeast Corridor 

(NEC) in New Jersey into New York’s Penn Station via the ‘A’ Yard at the western limit 

of the station complex. The new tunnel tracks would connect to existing yard tracks and 

to an extension of the ‘I’ Ladder, providing, in total, access to existing platform Tracks 1–

18. This connection would be crucial to fulfill the operational reliability and capacity 

requirement that would serve as the backbone to this project. 

The proposed two-track Amtrak tunnel alignment would travel across existing LIRR’s 

East Side Yards (ESY), between Eleventh and Tenth Avenues making the crucial 

connection into Tracks 1A, 2A, and the extended ‘I’ Ladder within ‘A’ Yard on the eastern 

side of Tenth Avenue. 

Preliminary meetings between Related and Amtrak began in June of 2012 in which 

Related inquired if the proposed track alignment could be shifted farther north to avoid a 

proposed tower in the terra firma area just east of the Eleventh Avenue viaduct. PB 

revised the alignment with no significant operational impacts to the track geometry. This 

revised alignment provided less impact to the LIRR Maintenance Facility (MOE building). 

This revised alignment serves as the basis for this current study. 

3.2 Review of Internal Space Requirements for Tunnel 

As part of the conceptual engineering studies performed by Parsons Brinckerhoff (PB) 

for Amtrak (Phase 1 – Section 1, Final Report submitted May 27, 2011), PB provided 

internal tunnel space proofing for cut-and-cover tunnels between Ninth and Twelfth 

Avenues. Since that report was released, PB was tasked to study the possibility of 

revising the track alignment to avoid a proposed overbuild structure on the terra firm 

area south of the East Rail Yards (ESY) adjacent to the Eleventh Avenue Viaduct. 

Using this revised track alignment; PB since re-reviewed the internal clearances as 

described below. Refinement to these dimensions and final verification of these 

dimensions will be completed during the Final Design stage with Amtrak and NJ Transit. 

The purpose of the memo submitted to Amtrak was to capture and verify that all overall 
Amtrak Gateway Project – Hudson Yards Study Final Report

 3-2 November 16, 2012

assumptions for vehicle carbody clearance, catenary clearance, low bench clearance, 

high bench clearance, fire-life safety, and ventilation issues have been captured and 

other major elements have not been excluded. 

The cross section in Figure 3-1 defines the internal space between the tunnel walls and 

roof. The structure is shown dashed. 

Figure 3-1: Tunnel Internal Space Requirements 
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The internal tunnel space was developed for the use of the following vehicles: 

Amtrak NJ Transit LIRR 

AEM-7 ALP-44 DM-30 

Acela Express ALP-45 M1/M3/M7 

HHP-8 ALP-46 

P32AC-DM Comet II, III, IV, V 

AM Fleet Arrow III, IV 

Viewliner Multilevel 

Heritage Baggage Car 

Plasser MFS-40

3.2.1 Static Vehicle Outline 

This envelope is provided by the vehicle manufacturer. This envelope is defined as the 

composite vehicle outline at a motionless position. 

3.2.2 Dynamic Vehicle Outline 

This envelope is provided by the vehicle manufacturer. Defined as the extreme car body 

displacement that can occur for any combination or rotational, lateral, and vertical car 

body movements that can occur when the vehicle is operating on level, tangent track. 

These car body movements are due to truck suspension movement, spring action, 

allowable wheel and wear, and permitted tolerances in vehicle construction. In addition 

to car body movements on level, tangent track, the effects of track curvature and 

superelevation must also be considered to allow additional room for vehicle overhang on 

curves and for vehicle lean when curves are superelevated. In addition to superelevated 

tracks, car body overhang on horizontal curvature also increases lateral displacement of 

the dynamic outline relative to the track centerline. Maximum center and end excesses 

are calculated by AREMA formulae using the proposed alignment curve data. 

3.2.3 Vehicle Clearance Envelope 

Is defined as the space occupied by the vehicle dynamic envelope, plus allowances for 

rail wear and track safety tolerances, plus a running clearance. The clearance envelope 

represents the space into which no physical part of the systems (other than the rail 

vehicle and passenger evacuation envelope) would be placed, constructed, or protrude. 

This assumes a maximum 6-inch perpendicular offset from the dynamic envelope that 

would occur near the top of the vehicle. This dimension would be less, lower on the 

carbody, adjacent to the high bench. 

3.2.4 Catenary Clearances 

Catenary clearances are determined based on the American Railway Engineering and 

Maintenance-of-Way Association (AREMA) criteria. This envelope contains provisions 

for air clearance, catenary uplift, catenary depth, and other tolerances defined within 

AREMA. The pantograph width is 7 feet (3 feet-6 inches from centerline of track to end 

horn). The contact wire height is proposed at a vertical dimension of 16 feet-3 inches 
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 3-4 November 16, 2012

above top of rail. The air gap requirement of 9 inches (greater than 150-foot support 

spacing) is assumed above this zone. This dimension could be reduced based on a 

shorter spacing in a later stage of design. 

3.2.5 High Bench 

Top of high bench is located 4 feet above top of low rail. The vertical face of the bench is 

5 feet-10 inches from centerline of tangent track. The vertical face of the bench is 

separated from the dynamic vehicle envelope by a radius of 2 inches. On curves, the 

gap must be increased by a distance of approximately 1.5 inches per degree of 

curvature, plus 1 inch per inch of superelevation if the bench is on the inside of the 

curve. This “gap” has been an acceptable tolerance for other railroad projects. 

Subsequent refinements to this dimension can be addressed at a later stage of design 

development. A minimum dimension of 2-foot-6 inch by 6-foot-8-inch passageway along 

the high bench is provided between the dynamic envelope and any continuous 

obstruction alongside the track and designated as passenger emergency evacuation 

path and maintenance personnel access. 

3.2.6 Low Bench 

Located at the opposite side of the track as the high bench, the low bench is a 

designated as a passageway for the conductor or other Amtrak personnel to access the 

vehicle at track level to connect brake hoses between vehicles or to accomplish other 

work to allow a disabled train to be pulled from the tunnel if needed. It is assumed, if 

needed, one would walk to the front or rear of the train on the high bench, and around to 

the other side of the train. This minimum envelope dimension of 2 feet-6 inches by 6 feet 

will be maintained. The top of the low bench would be the same elevation as top of rail. 

3.2.7 Ventilation 

Conceptual design has not advanced far enough to develop a complete emergency 

ventilation design. Preliminary conceptual design of the emergency ventilation system 

will be similar to the ARC tunnel. The Gateway tunnels will be ventilated via "push-pull" 

to meet NFPA 130 criteria. Fan plants will be located on the New Jersey side of the 

Hudson River and on 12th Avenue on the New York side of the Hudson River. 

Ventilation ducts will extend in the tunnels from each fan plant to part-way into the 

tunnels forming ventilation zones that cannot be occupied by more than one train at any 

given time. Access to each zone will be controlled by a fixed signal system that would 

preclude more than one train from entering an occupied ventilation zone. Each 

ventilation zone will be ventilated in "Push-Pull" mode and smoke and hot gases from 

the incident train will be contained in the ventilation zone such that trains occupying 

adjacent ventilation zones will not be contaminated from the incident zone. 

While the ARC tunnels were able to have ventilation ducts extend all the way to the 

proposed station, the Gateway tunnels will be unable to accommodate ventilation ducts 

east of Eleventh Avenue within the ESY due to spatial constraints imposed by proposed 

overbuild columns, proximity to the existing Amtrak Empire Line Tunnel, and LIRR MOE 
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facility. Therefore, to provide a ventilation zone from the proposed Twelfth Avenue Fan 

Plant to existing 'A' Yard that will meet NFPA 130 criteria, a fan plant is proposed to be 

built at the portal of the Gateway tunnels at the existing 'A' yard underneath the existing 

Lerner building. Providing a fan plant at the tunnel portal at Tenth Avenue will allow the 

stretch of tunnel across Hudson Yards to be as compact as possible eliminating a 

ventilation duct. 
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 4-1 November 16, 2012

4.0 SITE LOGISTICS WITHIN THE HUDSON YARDS

In order to maintain the platform schedule for the ERY, regardless of the construction 

option selected, the tunnel alignment will be constructed from Tenth Avenue heading 

west towards Eleventh Avenue. As the first portion of the tunnel alignment 

(approximately 400 feet) is completed, platform construction will commence working 

over the completed tunnel alignment. 

During tunnel construction, it is anticipated that the primary access to the alignment will 

be from Twelfth Avenue. See the attached plan showing the anticipated work zone and 

access route. It is not anticipated at this time that the existing ramp from Tenth Avenue 

will be viable access point. We anticipate having to remove this ramp early in the tunnel 

construction sequencing. 

During the construction phase, it is also anticipated that the tunnel access and work 

zone will likely impede access to yard tracks 0, 1, & 2. The actual phasing and duration 

of the yard track impedance will be further developed during the detailed design phase 

of the tunnel alignment. The TPC construction team will work closely with the LIRR to 

minimize the actual duration of any impacts to the yard tracks. The detailed logistics 

plans will be co-authored with the LIRR during the design phase of this project. 

In general, the anticipated construction sequence is as follows: 

1. Fence off construction zone 

2. Utility relocations, MOE building demolition, yard track removal 

3. Secant piling and Caisson construction 

4. Excavation/bracing 

5. Tunnel construction 

6. Backfill 

7. Platform foundation construction and Crane pad development (after the first 400 feet 

are constructed). MOE reconstruction and utility restoration is part of this work 

8. Yard track reconstruction 
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Figure 4-1: Anticipated Work Zone and Access Route 
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5.0 UTILITIES

5.1 General 

The construction of the proposed Amtrak tunnel within the Eastside Yard, will directly 

impact a portion of the existing utility infrastructure of the yard, including but not limited 

to storm sewer, sanitary sewer, electrical AC & DC power, communication, signals, gas 

and water (potable and fire protection). A conceptual utility investigation, following the 

usual practice and methods of a quality “D” subsurface utility investigation (ASCE 38-

02), was performed to identify potential utility impacts of construction. 

The investigation has been performed using available existing utility information and has 

been compiled on drawing numbers SK-UTL-01 thru SK-UTL-05. The subsurface utility 

information was obtained from drawings provided by Tutor-Perini and utility drawings 

from the original LIRR yard design drawings (1982). LIRR has not been specifically 

consulted regarding the potential utility impacts, and it should be assumed that LIRR will 

have concern over the construction operation and will require strict measures to maintain 

and protect their facilities as well as a review/approval period. It is also recommended 

that additional subsurface utility investigation be performed to supplement the developed 

information; including field investigations and test pits to increase the ASCE level of 

quality from the current “D” to “C”, “B” or “A” depending on the criticality of specific 

locations and utilities. 

We have assumed that the entire LIRR maintenance facility will be completely shut down 

so that no utility services will be required during the shutdown period. All existing utilities 

serving the maintenance facility will be restored in kind as they exist at this time. 

5.2 Storm & Sanitary Sewer 

5.2.1 Storm Sewer 

The proposed tunnel will require a portion of the system to be removed, relocated, and 

restored. The East Side Yard storm sewer system consists of a network of catch basins 

that collect surface run off, and elliptical reinforced concrete pipes (E.R.C.P.) that acts as 

the yard’s trunk line to convey storm water off site. The surface run off north of the 

empire line tunnel is collected and is pumped via a 24" force main into the yard's 

elliptical trunk line. The surface run off south of the empire line is also collected thru a 

network of catch basins, but is connected to the trunk line via gravity connections 

throughout the yard. 

Option 1: Temporary Gravity Sewer Replacement

The storm sewer system is required to be maintained throughout construction activities, 

and one option is to build a temporary gravity sewer to relocate the drainage system 

outside of the excavation zone to the extent possible. 
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E.R.C.P. Storm Sewers: The existing (E.R.C.P.) and associated manholes that will 

be impacted from the open cut of the proposed tunnel will be required to be removed 

and temporarily replaced. Crossing of the excavation will be required to connect to 

the existing sewer outside of the construction zone. In locations where excavation 

crossings are required, the temporary sewer replacement shall be an equivalent size 

ductile iron or fiberglass (CCFRMP) circular pipe that shall be hung, supported and 

protected. After tunnel construction has concluded, the trunk line sewer shall be 

replaced in kind in its original location. 

Surface run off collection network: The existing catch basins and intermediate 

storm sewer pipes that will be impacted from the open cut of the proposed tunnel 

construction will require removal and temporary replacement. Within the construction 

zone, temporary replacement of catch basins and sewers may be reduced based on 

staging, site set up and temporary grading. However, to maintain service for the 

existing catch basins located outside of the construction zone, excavation crossings 

will be required. In locations where excavation crossings are required, the temporary 

sewer replacement shall be an equivalent size ductile iron circular pipe that shall be 

hung, supported and protected. After tunnel construction has concluded, the sewers 

and catch basins shall be replaced in kind in its original location. 

Option 2: Temporary Pumping of Storm Sewer 

A feasibility study will be initiated to determine the possibility of extending the existing 

force main through a system of temporary force main piping to a point west of Eleventh 

Avenue. This would eliminate the need for a temporary gravity trunk line within the 

excavation zone. This concept would require the modification of the existing storm water 

pumping system. If this is not feasible, an auxiliary temporary pumping system can be 

provided within the work zone to convey storm water from the end of the existing force 

main to a point beyond the work zone. After tunnel construction has concluded, the 

sewers and catch basins shall be replaced in kind in their original locations. 

5.2.2 Sanitary Sewer 

The proposed tunnel construction activities will impact the existing sanitary sewer 

servicing the LIRR maintenance facility. The existing sewer shall be removed and 

replaced in kind after construction of the tunnel roof. 

5.3 Electrical – AC & DC Power

5.3.1 AC Power 

The proposed tunnel construction activities will impact the existing AC Power system 

that currently provides lighting for the South Access Road and exterior of the 

Maintenance Building and provides facility power to the interior of the building. 

Therefore, it is assumed that during construction activities, the impacted portion of the 

AC system serving lighting and the Maintenance Building will be temporarily taken out of 

service and temporary construction lighting be provided. 
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AC Power MH’s and conduits also serve to connect the LIRR Emergency Facilities 

building just west of Eleventh Avenue to portions of the yard that are to remain in 

operation during the tunnel construction. To keep this portion of the impacted AC system 

operable during construction, MH’s and conduits will be maintained as is or in a 

temporary condition. If construction activities are facilitated by removing this essential 

system a temporary emergency generator will be provided for the use of the LIRR. Any 

portion of the AC system removed will be restored in kind upon completion of the 

proposed tunnel roof. 

5.3.2 DC Negatives 

The proposed tunnel construction activities will impact the existing DC Negative system 

for the portion of the LIRR yard serving the maintenance facility. Therefore, it is assumed 

that during construction activities, the impacted portion of the DC Negative system will 

be temporarily taken out of service. If construction activities are facilitated by removing 

the deactivated system it will be restored in kind upon completion of the proposed tunnel 

roof. 

5.3.3 DC Positives 

The proposed tunnel construction activities will impact the existing DC Positive system. 

One segment of the impacted DC Positive serves the portion of the LIRR yard serving 

the maintenance facility. It has been assumed that the LIRR maintenance facility will be 

shutdown and the tracks entering it deactivated. Therefore, during construction activities, 

the impacted portion of the DC Positive system will be temporarily taken out of service. If 

construction activities are facilitated by removing the deactivated system it will be 

restored in kind upon completion of the proposed tunnel roof. 

Another segment of the impacted DC Positive system serves tracks north of the 

proposed construction area that are to remain in operation. Specifically DC MH P8 is 

within the proposed tunnel excavation and must be temporarily relocated or maintained 

in place in a temporary condition (such as a wooden box). In addition if it is determined 

that DC MH P8 conflicts with the proposed tunnel roof a rerouting of the system from 

MHs P9 and P6 to P8 will be required. Temporary and/or final rerouting of the DC MH 

P8 system will have to be staged to provide service to all active tracks with minimal 

disruptions (off peak only). Final restoration of the DC power system must be 

coordinated to accommodate the possible conflict between bottom of DC MH P8 and the 

proposed tunnel roof by providing an alternative MH location or modified MH and tunnel 

roof. 

5.4 Signal and Communication 

5.4.1 Signals 

The proposed tunnel construction activities will impact the existing signal system for the 

portion of the LIRR yard serving the maintenance facility. The impacted portion of the 
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signal system will be temporarily taken out of service. If construction activities are 

facilitated by removing the deactivated system it will be restored in kind upon completion 

of the proposed tunnel roof. It remains to be confirmed that there is no existing signal 

equipment within the LIRR Maintenance Building that is required for operation of the 

portion of the yard that must remain in operation during tunnel construction. 

5.4.2 Communications 

The proposed tunnel construction activities will impact the existing communications 

system for the portion of the LIRR yard serving the maintenance facility. The impacted 

portion of the communications system will be temporarily taken out of service. If 

construction activities are facilitated by removing the deactivated system it will be 

restored in kind upon completion of the proposed tunnel roof. 

5.5 Water (Fire & Potable) and Gas 

5.5.1 Water (Fire & Potable) 

The 10” fire protection and 6” potable water lines are impacted by the proposed open cut 

construction. Upon initial review, it appears that the fire protection and potable water 

mains service areas outside of the construction zone. Therefore, the water mains will be 

temporarily relocated outside of construction zone. Any exposed water mains will be 

protected from freezing by insulation and/or heat trace. 

5.5.2 Gas 

Upon initial review it appears that the 5-inch gas line services only the LIRR 

maintenance facility. It has been assumed that the gas line can be deactivated and 

capped outside of the construction influence area. If the existing gas line is removed 

during construction it will be replaced as required by LIRR. 
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6.0 DESIGN SOLUTIONS & CONSTRUCTION OPTIONS

6.1 Subdivision of Site

For the purpose of the study the proposed tunnel alignment has been divided into four 

distinct sections as delineated in drawing SK-ALT1-01. The sections reflect the 

significantly different physical constraints and characteristics imposed along the tunnel 

alignment by the layout and loads of the planned overbuild structures, as well as from 

the existing Amtrak Empire Line Tunnel and the LIRR railroad infrastructure and MOE 

Buildings. The main characteristics of each section are summarized below: 

Section A: The southwest end of the alignment, adjacent to Eleventh Avenue, is 

characterized by the high column loads imposed by the Overbuild 

Tower D (10,000 kip column loads). The tunnel alignment is also at its 

deepest in this section. 

Section AB: This section of the tunnel alignment is occupied by shop tracks 

serving the MOE Building and is characterized by multiple columns 

carrying the Overbuild platform only (2,000 kip loads). 

Section B: This section of tunnel is in close proximity to the existing Amtrak 

Empire Line Tunnel. This area is also characterized by multiple 

columns carrying high loads from Overbuild Structures (6,000 kip 

column loads). 

Section C: The western end of the tunnel is occupied by the LIRR MOE Buildings 

and is characterized by multiple high column loads from the Overbuild 

Structures (6,000 kip column loads). The tunnel is also at its 

shallowest along this section. 

6.2 Conceptual Design Alternates 

Cognizant that the potentially complex easement arrangements for the future Gateway 

Tunnel, LIRR facilities and Overbuild structures have yet to be resolved, three 

conceptual design solutions have been developed for the permanent structures. The 

design solutions, designated Alternates 1, 2 and 3, provide different levels of structural 

separation between the proposed Gateway Tunnel and the foundations of the Overbuild 

structures as described below: 

The tunnel structure, which is founded on rock, is designed to carry the column loads of 

the overbuild structures. This is the simplest construction solution which utilizes the 

proposed tunnel as a pad or pseudo-strip foundation for the overbuild structures. 

However, integrating the tunnel and overbuild structures complicates interface issues 

between the structures such as railroad easement arrangements, isolation of railroad 

vibrations from the overbuild structures, fire & life safety and terrorist threat mitigation 
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measures, and demarcation of maintenance responsibilities for the structures. These 

interface issues, including vibration isolation, will be addressed during detail design. 

Figure 6-1: Alternative 1: Fully Integrated Tunnel and Overbuild Foundation 

Structures 

The Alternative 2 design solution transfers the overbuild column loads onto caisson 

foundations located on either side of the tunnel. Isolation casing is utilized at tunnel 

elevation to isolate the caisson foundations from the tunnel box and transfer the 

overbuild column loads below the invert of the tunnel. This design solution eliminates the 

majority of interface issues between the tunnel and overbuild structures. 

Figure 6-2: Alternative 2: Fully Isolated Tunnel and Overbuild Foundation 

Structures 

Overbuild Foundation Load (size & locations vary)

Overbuild Foundation Load (size & locations vary)

Isolation Casing for Caisson
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The Alternative 3 design solution transfers the overbuild column loads onto caisson 

foundations located either side of the tunnel and along the dividing wall between the 

tracks, thereby reducing the span and size of the overbuild transfer structures. Isolation 

casing is again utilized at tunnel elevation to isolate the caisson foundations from the 

tunnel box and transfer the overbuild loads below the invert of the tunnel. While this 

design solution will isolate the overbuild loads from the tunnel, it nevertheless also 

introduces more complicated structural joint and waterproofing details between the 

structures and many of the interface issues associated with the fully integrated design 

solution will remain pertinent in this case. 

Figure 6-3: Alternative 3: Partially Isolated Tunnel and Overbuild Foundation 

Structures 

6.3 Construction Options 

Each of the above conceptual design solutions was developed along the alignment to 

evaluate their technical feasibility and to determine costs and schedule implications for 

constructing the tunnel’s structural box. Recognizing that construction of the tunnel will 

be dependent on the availability of funding, the construction options listed in Table 6-1 

and described below were considered. 

Overbuild Foundation Load (size & locations vary)

Isolation Casing for Caisson
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Table 6-1: Tunnel Construction Options 

Alternative 

Design 

Concept 

Construction 

Options Tunnel Construction 

Alt. 1 Fully Integrated Option 1 Full Build 

Alt. 2 Fully Isolated 

Option 1 Full Build 

Option 2A Deck Supported on Full Depth Secant Pile 

Walls to facilitate Future Build 

Option 2B Deck Supported on Independent Caissons to 

facilitate Future Build 

Option 3 Easement Corridor Only 

Alt. 3 Partially Isolated 

Option 1 Full Build 

Option 2A Deck Supported on Full Depth Secant Pile 

Walls to facilitate Future Build 

Option 2B Deck Supported on Independent Caissons to 

facilitate Future Build 

Option 3 Easement Corridor Only 

Option 1: Full construction of the tunnel’s structural box concurrent with the 

overbuild construction activities 

Option 2: Configuration of the overbuild foundations and construction of a deck 

structure at or above the roof elevation of the tunnel to support the Hudson Yard’s 

railroad infrastructure/operations in order to preserve an easement and facilitate 

independent construction of the tunnel’s structural box at some future date. This 

option has been further subdivided as follows: 

 Option 2A: Secant pile walls drilled full depth through rock and toed below the 

invert level of the future tunnel are utilized to support the deck structure. The 

secant pile walls also serve as the temporary excavation support during 

construction of the deck and overbuild foundations and will provide temporary 

sidewall support during subsequent mining of the tunnel. 

 Option 2B: The temporary deck structure is supported on pre- installed 

caissons spaced along the tunnel alignment. Secant pile walls, drilled into the top 

of rock, are used to support the temporary excavations for construction of the 

deck and overbuild foundations along the tunnel alignment. Rockbolts will be 

utilized to support rock faces exposed at locations where the excavations extend 

into rock. 

Option 3: This ‘Not to Preclude’ option entails configuring and constructing the 

overbuild foundations to preserve an easement corridor for constructing of the tunnel 

box separately in the future. While this option will preserve a pathway to construct 

the tunnel independently, no other measures are incorporated during construction of 

the overbuild structures to facilitate tunnel construction. 
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6.4 Alternative 1: Fully Integrated Tunnel and Overbuild Foundation Structures 

6.4.1 Design Concept 

The tunnel is designed to directly support the columns of the Overbuild structures. The 

tunnel invert is founded in rock and serves as the foundation for the Overbuild 

structures. This design concept is technically viable along the entire tunnel alignment 

within the Hudson Yards. As the column loads vary along the tunnel alignment the 

dimensions of the tunnel box will also vary as illustrated in drawing SK-ALT1-02. 

6.4.2 Construction Option 1 

Full Construction of Integrated Tunnel and Overbuild Foundations

Fully integrating the tunnel and overbuild foundations requires the tunnel box to be 

constructed concurrently with the overbuild structures. Accordingly, Option 1 is the only 

means of construction if this design solution is selected. 

The initial stage of construction will entail relocations of railroad infrastructure and 

utilities to accommodate open cut excavation of the deep trench in which the tunnel will 

be constructed. It also requires demolition of sections of the existing LIRR MOE 

structures within Section C. At the same time the support of excavation (SOE) walls will 

be installed to facilitate excavation down through the overburden soils to rock. Due to the 

relatively high groundwater elevation and likelihood of contamination, the study 

anticipates secant pile walls toed into rock will be utilized for the SOE. Alternative 

methods could be explored during detailed design. As much as possible tie back 

anchors will be utilized in lieu of struts to support the SOE walls. At Section B, there is 

insufficient space to accommodate the SOE between the Empire Line Tunnel and the 

trench for the Gateway tunnel. Therefore the secant pile wall in this vicinity is anticipated 

to cross over and run on the north side of the Empire Line Tunnel. Alternatively, bracing 

at the roof level of the Empire Line Tunnel could be considered. 

Mass excavation of the overburden soils will follow installation of SOE walls. The 

excavation will be extended through rock to the tunnel invert level utilizing controlled 

blasting techniques. Channel drilling and rock splitting techniques will also be necessary 

in close proximity to the Empire Line. Pattern rock bolting will be used to temporarily 

support the rock faces in the trench. 

Shotcrete will be applied to the rock faces in the trench and lower sections of the secant 

pile walls to provide an adequately smooth surface to attach the waterproofing fleece 

and membrane used to waterproof the new tunnel. A mud mat will also be placed in the 

invert. The permanent cast-in-place reinforced concrete tunnel invert, walls and roof will 

be placed following installation of the waterproof membrane. 

The final stages of construction will entail completing the overbuild column connections 

to the tunnel box, cutting off the top of the secant pile walls, backfilling the tunnel trench 

and reinstating the railroad infrastructure and utilities. 
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6.5 Alternative 2: Fully Isolated Tunnel and Overbuild Foundation Structures 

6.5.1 Design Concept 

In this design concept the columns of the overbuild structures are supported on transfer 

beams to transfer the building loads onto caisson foundations located on either side of 

the tunnel. Isolation casing is utilized at tunnel elevation to isolate the caisson 

foundations from the tunnel box and carry the overbuild column loads below the invert of 

the tunnel. 

The tunnel’s structural box is only designed for the ground and groundwater pressures 

and the railroad infrastructure and operating surcharge loads within the Yard. While the 

structural dimensions of the tunnel roof, invert and walls will be reduced compared to 

those of the fully integrated structure (Alternative 1), buoyancy measures are required to 

counter hydraulic uplift pressures. For the purpose of this study, friction piles have been 

allowed for in the tunnel invert. Other options such as double corrosion protection 

anchors or rock keys can be explored during detailed design. 

Transferring the largest column loads onto the caissons either side of the tunnel will 

require substantial transfer structures. Significantly, due to the relatively shallow cover 

above the proposed tunnel at Section C, under the LIRR MOE structures, there will be 

insufficient room to accommodate the required transfer beam for the overbuild column 

loads if the transfer structure is located immediately above the tunnel roof. 

Since the tunnel and overbuild foundation structures are entirely independent of each 

other, the structures can be constructed concurrently or separately. Therefore, 

construction Options 1, 2 and 3 are available as described below. 

6.5.2 Construction Option 1 

Full Construction of Tunnel and Overbuild Foundations

Construction will begin with railroad infrastructure and utility relocations and demolition 

of sections of the existing LIRR MOE structures to accommodate open cut excavation of 

the deep trench to construct the tunnel. The overbuild caisson foundations and tunnel 

friction piles will also be drilled at this stage in conjunction with the SOE secant pile walls 

described earlier for the fully integrated tunnel and overbuild design solution. 

Mass excavation of the overburden soils within the tunnel trench will be followed by 

excavation of the rock to formation level utilizing the same controlled blasting/rock 

splitting techniques and rock support measures described earlier. A smoothing layer of 

shotcrete will again be applied to the rock faces and lower sections of the secant pile 

walls for the tunnels waterproofing fleece and membrane. A mud mat will also be placed 

in the invert, accommodating the counter buoyancy friction piles that will be integrated 

into the tunnel invert. The permanent cast-in-place reinforced concrete invert, walls and 

roof will be placed following installation of the waterproof membrane. 
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The final stages of construction will entail constructing the overbuild transfer beam and 

caisson connections above the tunnel roof elevation. Styrofoam or similar compressible 

material will be used to infill the annulus between the tunnel roof and transfer structures. 

The structural connections between the transfer beams and column footings will then be 

completed and where applicable the tops of the secant pile walls cut. Tunnel 

construction is completed by backfilling the tunnel trench and reinstating the railroad 

infrastructure and utilities. 

6.5.3 Construction Options 2A and 2B 

Construction of Tunnel Decking and Overbuild Foundations 

In lieu of fully constructing the tunnel box in conjunction with the overbuild structures, 

construction Options 2A and 2B entail constructing a deck structure over the tunnel 

alignment as described in section 6.2. Since the overbuild foundation transfer structures 

will already bridge over the tunnel alignment, the deck structure is only required between 

the transfer structures. 

Option 2A, incorporating full depth secant pile walls, is only considered viable within 

Section AB of the alignment where the spacing between the overbuild foundations 

permits construction of the walls (see drawing SK-ALT2-01). In Sections A and B the 

close spacing between the overbuild columns renders this option impractical. 

Option 2B is viable at Sections, A AB and B (see drawings SK-ALT2-02, SK-ALT2-03 

and SK-ALT-04. 

Future Tunnel Construction Stages

Future tunnel construction will entail mining the rock under the deck (and between the 

secant pile walls where applicable) by controlled blasting in conjunction with channel and 

line drilling and rock splitting techniques to minimize impacts to the deck and overbuild 

caisson foundations. The steel isolation casing used to isolate the overbuild caissons 

from the final tunnel will afford some protection to the overbuild caissons during mining. 

Nevertheless, noise and vibrations associated with blasting and other construction 

activities may cause nuisance to occupants in the overbuild buildings. 

The friction piles required to counter hydraulic uplift pressures in the final tunnel 

structure will be drilled following completion of tunnel excavation. The headroom within 

the tunnel will be approximately 25 feet at this stage of the construction. Shotcrete will 

be applied to the exposed secant pile sideswalls and/or rock faces as applicable in order 

to provide an adequately smooth surface to attach the waterproofing fleece and 

membrane used to waterproof the new tunnel. At the locations of the overbuild 

foundation transfer structures styrofoam or similar compressible material will be used to 

infill the annulus to the tunnel roof prior to installing the waterproofing fleece and 

membrane. In the invert the mud mat will be placed allowing the counter buoyancy 

friction piles to be integrated into the tunnel invert. The permanent cast-in-place 
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reinforced concrete tunnel invert, walls and roof will then be placed following installation 

of the waterproof membrane. 

6.5.4 Construction Option 3 

Overbuild Foundations Construction

Since these structures will be completely independent of the future tunnel construction 

they can be located at relatively shallow depth. Open cut excavation will only be required 

to construct the overbuild transfer structures. Steel sheeting can be installed instead of 

secant pile walls to support the smaller individual excavations required to construct each 

overbuild transfer structure (see drawings SK-ALT2-05, SK-ALT2-06 and SK-ALT2-07. 

Future Tunnel Construction Options

Future tunnel construction methods are discussed separately in Section 6.7. 

6.6 Design Alternative 3: Partially Isolated Tunnel and Overbuild Foundations 

6.6.1 Design Concept 

This design solution is similar to the fully isolated design concept in that it transfers the 

overbuild column loads onto caisson foundations which carry the loads below the tunnel 

invert level. However, in this case caissons are also installed along the tunnel center wall 

which divides the tracks in order to reduce the span and size of the overbuild transfer 

structures. Isolation casing is again utilized at tunnel elevation to isolate the caisson 

foundations from the tunnel box and transfer the overbuild loads below the invert of the 

tunnel. Nevertheless, incorporating the center column through the middle of the tunnel 

means the structures will not be entirely isolated from one another. Structural joint 

details and waterproofing to accommodate the center columns will be significantly more 

complex. Furthermore, the dimension of the center wall will increase because of the 

inclusion of the center column. Since the overbuild loads are not transferred to the 

tunnel, the tunnel’s structural box will be designed only for the ground and groundwater 

pressures and the railroad infrastructure and operating surcharge loads, thereby 

maintaining thinner tunnel invert, walls and roof relative to those of the fully integrated 

structure (Alternative 1). For the purpose of the study, friction piles have again been 

allowed for in the tunnel invert in order to counter hydraulic uplift pressures. 

While the center column will enable the transfer structure to be reduced in size relative 

the fully isolated configuration, there is still insufficient cover under the LIRR MOE 

structures at Section C to accommodate the beam. 

With the loads of the overbuild structures being isolated from the tunnel, the structures 

can be constructed concurrently or separately. Therefore, construction Options 1, 2 and 

3 are again available although complicated by the structural and waterproofing details to 

accommodate the center columns. 
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6.6.2 Construction Option 1 

Tunnel construction will be similar to that described in section 6.5.2 for Alternative 2. 

6.6.3 Construction Options 2A and 2B 

Decking and Overbuild Foundations Construction

Construction will be similar to that described in Section 6.5.3 for Alternative 2. Option 2A 

is only viable in Section AB. Option 2B is viable in Sections A, AB and B. See drawings 

SK-ALT3-01, SK-ALT3-02, SK-ALT3-03 and SK-ALT3-04. 

Future Tunnel Construction Stages

Tunnel construction will be similar to that described in section 6.5.3 for Alternative 2. 

6.6.4 Construction Option 3 

Overbuild Foundations Construction

Overbuild foundation construction will be similar to that described in section 6.5.4 for 

Alternative 2 with the exception of drilling the additional center caissons. See drawings 

SK-ALT3-05, SK-ALT3-06 and SK-ALT3-07. 

Future Tunnel Construction

Future tunnel construction methods are discussed separately in section 6.7. 

6.7 Option 3 (Not to Preclude): Future Tunnel Construction Methods 

Future tunnel construction for the ‘Not to Preclude’ case could utilize cut-and-cover 

excavation methods or underground mining techniques. Cut-&-cover excavation 

methods would be most disruptive to future railroad operations within the Hudson Yards. 

Underground mining methods would likely also cause some disruption to the railroad but 

not to the physical extent of cut-and-cover methods. However, mining methods will be 

slower and carry potentially higher risk. Possible tunnel construction methods are 

described below. 

6.7.1 Cut-and-Cover Tunnel Construction 

Stage 1 of future tunnel construction by cut-and-cover methods would entail railroad 

infrastructure and utility relocations. Combinations of secant pile wall construction, steel 

sheeting and soldier pile and lagging could then be utilized to negotiate the existing 

overbuild foundations and provide excavation support down to rock. 

Stage 2 would entail mass excavation of the overburden soils along the tunnel alignment 

between the overbuild foundations to the top of rock. Excavation would continue 

vertically in rock to the tunnel invert level utilizing controlled blasting techniques. 

Channel drilling and rock splitting techniques would also be necessary in closest 

proximity to the Empire Line Tunnel and the already constructed overbuild caisson 

foundations. Pattern rock bolting would be used to temporarily support the rock faces in 
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the trench. Sequential mining techniques would be used undercut the soil and rock 

under the overbuild transfer beams between the isolated caissons. The undersides of 

the transfer beams can be exposed since the beams are supported by the caissons. If 

the transfer beams are shallow relative to the tunnel elevation, pre-support methods 

such as spiles or grouted canopy tubes could be used to retain the ground between the 

tunnel roof the underside of the overbuild transfer structures. 

Stage 3 of tunnel construction requires drilling the friction piles in the floor of the tunnel 

excavation. The piles will be incorporated in the invert of the final tunnel structure to 

counter hydraulic uplift pressures. The headroom within the tunnel will be approximately 

25 feet at this stage of the construction. Other options, such as blasting keys into the 

rock sidewalls at invert level could also be investigated. 

Stage 4 involves shotcreting the exposed rock sidewalls and covering the rock bolt 

hardware that extend from the rock face in preparation for the waterproofing fleece and 

membrane. In the invert the mud mat will be placed accommodating the overbuild center 

column caissons (where present) and allowing the counter buoyancy friction piles to be 

integrated into the tunnel invert. The permanent cast-in-place reinforced concrete invert, 

walls and roof will be placed following installation of the waterproof membrane. 

Stage 5 will entail backfilling the tunnel trenches and reinstating the railroad 

infrastructure and utilities. 

6.7.2 Mined Tunnel Construction – Utilizing Jet Grouting or Ground Freezing 

In order to facilitate underground tunnel construction the groundwater and overburden 

soils will first need to be treated. Possible ground treatment methods include jet grouting 

and ground freezing. The following ground treatment options have been considered: 

Jet Grouting 

Ground Freezing 

Stage 1 of construction would entail implementation of the selected ground treatment 

method. Jet grouting from the surface would be most disruptive to the LIRR 

infrastructure and operations. However, implementing ground freezing from the surface 

would also entail significant disruption in order to drill the freeze pipes and install/operate 

the freezing infrastructure. Horizontal freezing operations from within the tunnel would 

minimize surface disruption to the rail yard but would be a very slow process because 

the freeze could only be advanced in nominal 100-foot segments ahead of the tunnel 

face due to the limitations of horizontal drilling. The freezing process will take several 

months following installation of the freeze pipes. Freezing can potentially induce 

significant heave and expansion forces during the freeze process and subsequent 

settlement once the freeze is turned off. 
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Stage 2 of the construction would entail mining through the treated ground in one or both 

directions depending on site access. Mining would progress utilizing pre-support spiles 

installed in front of the mining face to prevent raveling or collapse of any overburden 

soils in the roof area of the tunnel. The pre-support is installed in front of each advance 

of the tunnel face. Controlled blasting methods would be utilized in combination with 

channel/line drilling and rock splitting techniques where necessary. Initial rock support in 

the tunnel would comprise pattern rock bolting and shotcrete, together with steel ribs or 

lattice girders where required. 

Stage 3 will entail drilling the friction piles in the floor of the tunnel excavation. The piles 

will be incorporated in the invert of the final tunnel structure to counter hydraulic uplift 

pressures. The headroom within the tunnel will be approximately 25 feet at this stage of 

the construction. Other options, such as blasting keys into the rock sidewalls at invert 

level could also be investigated. 

Stage 4 involves spraying smoothing shotcrete if not already incorporated in the initial 

support system in stage 2. In the invert the mud mat will be placed accommodating the 

overbuild center column caissons (where present) and allowing the counter buoyancy 

friction piles to be integrated into the tunnel invert. The permanent cast-in-place 

reinforced concrete invert, walls and roof will be placed following installation of the 

waterproof membrane. 

6.8 Summary of Construction Solutions for Pricing 

Table 6.2 defines five viable construction options, or Pricing Solutions, that have been 

developed from the technical evaluations described in this section. In all cases the 

Pricing Solutions require construction of the fully integrated tunnel (Alternative 1) under 

the LIRR MOE Building (Section C) due to the limited space above the tunnel. Pricing 

Solution 2B reflects incorporating a middle caisson for the partially isolated design 

concept (Alternative 3). 

Table 6-2: Pricing Solutions 

Pricing 

Solution 

Design Alternative/Construction Option at Site Locations 

A AB B C 

1 Alt.1/Opt.1 Alt.1/Opt.1 Alt.1/Opt.1 Alt.1/Opt.1 

2A Alt.2/Opt. 2B Alt.2/Opt.2A Alt.2/Opt.2B Alt.1/Opt.1 

2B Alt.3/Opt.2B Alt.3/Opt.2A Alt.3/Opt.2B Alt.1/Opt.1 

2C Alt.2/Opt.2B Alt.2/Opt.2B Alt.2/Opt.2B Alt.1/Opt.1 

3 Alt.2/Opt.3 Alt.2/Opt.3 Alt.2/Opt.3 Alt.1/Opt.1 

Cost estimates and construction schedule implications for these construction Pricing 

Solutions are presented separately in this report. 
Amtrak Gateway Project – Hudson Yards Study Final Report

 7-1 November 16, 2012

7.0 COST ESTIMATES AND CONSTRUCTION SCHEDULES

7.1 Cost Estimates 

Cost estimates for the present day and future tunnel construction elements for each of 

the Pricing Solutions identified in the previous section are presented in Table 7-1. 

7.2 Construction Schedules

Construction schedules for Pricing Solutions 1, 2A/2B/2C and 3 are shown in Tables 7-2, 

7-3, and 7-4, respectively. 
Amtrak Gateway Project – Hudson Yards Study Final Report

7-2 November 16, 2012

Table 7-1: Pricing Solutions 
Amtrak Gateway Project – Hudson Yards Study Final Report

7-3 November 16, 2012

Table 7-2: Amtrak Tunnel Construction – Pricing Solution 1 
Amtrak Gateway Project – Hudson Yards Study Final Report

7-4 November 16, 2012

Table 7-3: Amtrak Tunnel Construction – Pricing Solution #2A, 2B, and 2C 
Amtrak Gateway Project – Hudson Yards Study Final Report

7-5 November 16, 2012

Table 7-4: Amtrak Tunnel Construction – Pricing Solution #3 
Amtrak Gateway Project – Hudson Yards Study Final Report

 8-1 November 16, 2012

8.0 CONCLUSIONS & RECOMMENDATIONS

The fully integrated cut-and-cover tunnel segment (Pricing Solution 1) appears to be the 

most efficient and practical solution available. Although it was anticipated at the onset of 

this study that the solutions with a full deck isolating the overbuild structures from the 

tunnel (Pricing Solutions 2A, 2B, 2C) were going to be monetarily less to construct 

during the construction of the overbuild structures, the cost analysis did not support it. At 

the onset of the study, it was expected that Pricing Solution 1 would have the greatest 

initial cost and that Pricing Solutions 2 (2A, 2B, 2C) and 3 would each be lower cost 

options. However, the analysis shows minor difference in initial construction cost 

between options. This can be explained as follows: 

The execution of all five pricing solutions would require essentially the same site 

preparation costs, including removal and replacement of the LIRR MOE shop 

building, shop tracks, and utilities. All of the solutions would require the construction 

of a fully integrated cut-and-cover tunnel for approximately one-third of the tunnel 

length. 

For the deck options (Pricing Solutions 2A, 2B, 2C), it was determined that the 

protective deck and transfer beams would not be supported solely on the secant pile 

support of excavation system. Instead, it would be necessary to install caissons to 

carry the high loads. 

Pricing Solutions 2A and 2B would require a large quantity of secant pile walls in 

rock to advance the piles below the elevation of future tunnel invert. 

The partially isolated Pricing Solution 2C (with an embedded center caisson) would 

allow the reduction in depth and cost of transfer girders but would not offset the 

additional cost of the center caissons. 

It will be necessary to resolve technical and non-technical construction-related issues 

during the design phase of the project. These include the interface between building 

owners and LIRR, the remediation of railroad vibrations from the overbuild structures, 

and the demarcation of maintenance responsibilities of the tunnel structures. 
Amtrak Gateway Project – Hudson Yards Study Final Report

 November 16, 2012

Appendix – 

Engineering Drawings 
DRAFT NOVEMBER 9, 2012

EAST SIDE YARD

AMTRAK TUNNEL ALTERNATIVE STUDY
DRAFT NOVEMBER 9, 2012

EAST SIDE YARD

AMTRAK TUNNEL ALTERNATIVE STUDY
DRAFT NOVEMBER 9, 2012

EAST SIDE YARD

AMTRAK TUNNEL ALTERNATIVE STUDY
DRAFT NOVEMBER 9, 2012

EAST SIDE YARD

AMTRAK TUNNEL ALTERNATIVE STUDY
DRAFT NOVEMBER 9, 2012

EAST SIDE YARD

AMTRAK TUNNEL ALTERNATIVE STUDY