APPENDIX Construction Phasing (Build Alternative)

C

BWI Rail Station Improvements and Fourth Track Project Environmental AssessmentC-1

C APPENDIX CCONSTRUCTION PHASING (BUILDALTERNATIVE)

A major design objective of the project was to implement a cost-effective approach thatallowed for construction to proceed in a timely manner, while minimizing negative impactson railroad operations, minimizing environmental impacts, and maintaining vertical andhorizontal clearances along the NEC.

A major consideration of the design approach for the project was maintenance of Amtrakand MARC services during construction. Amtraks requirement is that at least two tracksremain operational at all times through the project limits and each of the two tracks has anoperational platform at the BWI Rail Station. As such, the effects of construction on railtraffic will influence the sequence and scheduling of construction activities. The BuildAlternative has been configured to accomplish the required maintenance of Amtrak andMARC services. Overall construction time to fully implement the facilities and train controlsystems would be approximately 42 months.

Construction access from outside the NEC onto Amtrak right-of-way will primarily useexisting Amtrak maintenance access locations. See Appendix C for more details regardingconstruction phasing.

C.1 TRACK REALIGNMENT AND NEW FOURTH TRACK

The construction of the new fourth track locates the new track east of the existing tracks forthe entire limits of construction. This minimizes potential disruption of existing Amtrak andMARC services and simplifies Amtrak train control operations during the constructionphase.

C.2 BWI RAIL STATION AREA

The construction of the BWI Rail Station including new platforms, new overhead walkway,and new fourth track and has been configured to maintain service on two tracks and twoplatforms with minimal disruption. While the proposed realignment of the tracks doesrequire relocation of the existing station electrical/generator room (located at the rear of theexisting station), the operations at the existing station would be allowed to continue duringconstruction. Track A, in the immediate vicinity, would not need to be completed and in useuntil the replacement station and all electrical and system services are on line.

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The following sections present the demolition/construction phasing sequence for theproposed track realignment and new fourth track at BWI Rail Station. The existing stationand its egress elements must remain in operation during the construction process tomaintain the required passenger services.

The intent of the construction approach is that the existing station building will remainoperational during the construction of the following new elements:

x New and shifted platformsx Canopiesx Pedestrian bridgex Pedestrian walkway realignmentx Egress elementsx New fourth trackx New station building

Construction Phase 1 Site Preparation

The first construction phase includes installing construction fencing and staging areas;installing sediment and erosion control; providing stone for construction access road entryto work zones; and providing measures to address temporary replacement of the existingdetention facility located north of the existing garage. A barrier/fence would be constructedaround the Higgins Site so that this archaeological site would not be impacted duringconstruction.

During this phase of construction, the existing garage area walkway, station canopy, station,platforms, stair towers, and pedestrian bridge would remain operational. Service would bemaintained on all existing tracks and platforms.

Construction Phase 2 New Pedestrian Bridge and Station Facility

Phase 2A. Phase 2A includes the following activities:

x Starts construction of the retaining walls, earthwork, and detention vault at the newstation facility

x Builds a temporary construction access road along the northern limit of the LOD toallow access to the area just east of the existing northbound platform in the vicinity ofthe proposed pedestrian bridge

x Starts construction of the new pedestrian bridge including all stairs, escalators, andelevators at the southbound platform and all vertical circulation elements at thenorthbound platform (except the stairs and escalator located between the existing stationfacility and the new Pedestrian Bridge)

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x Builds a portion of the retaining wall located north of the BWI Rail Station facilityfoundation

x Constructs the southern section and the northern section of the new northboundplatform

x Constructs the new section of MDOT walkway between the existing MDOT walkwayand the new pedestrian bridge

x Constructs storm drainage, utilities, sub-ballast, ballast, rail at New Track 1 and NewTrack 2 (except at the existing station facility/east stair tower area)

x Constructs a portion of the new center platform located north of the existing northboundplatform (to the extent it is preferable to do in this phase), which will become the easternportion of the new center platform

x Constructs new catenary structuresPhase 2B. Phase 2B includes closing a portion of the northbound platform to install centersupport columns/temporary supports, as appropriate, at the new pedestrianbridge/walkway. However, approximately 700 to 800 feet of the existing northboundplatform would remain in operation. The final design of the pedestrian structure willconsider this phasing so that columns installed at this time (the temporary supportarrangement) will only use the eastern side of the new center platform as Existing Track 1must remain in service during Phase 2.

Phase 2C. Phase 2C completes construction of the new station facility building, the buslanes, busbays, the sidewalk north of the bus lanes, and the pedestrian bridge/walkwayover Existing Tracks 1, 2 and 3. However, the center platform vertical circulation connectionto the pedestrian bridge, including elevators and escalators, would not be complete.

Phase 2D. Phase 2D temporarily reroutes the taxi queue to the new bus lanes and completesconstruction of the kiss & ride located north of the parking garage and south of the buslanes. This phase would complete construction of parking lots, sidewalks and landscapingsouth of the bus lanes.

Existing Platforms 1 and 2, station canopy, station, stair towers, and pedestrian bridgewould remain in operation during all of Phase 2 construction. Service would be maintainedon all existing tracks.

Construction Phase 3 Open Pedestrian BridgePhase 3 does not involve construction but opens the new bus lanes, busbays and sidewalks.During this phase, the taxi queue is permanently relocated to the existing alley between thenorth and south sections of the garage. Although the pedestrian bridge would be open, itwould not provide access to the center platform.

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Construction Phase 4 Temporary Removable Metal Walkway Pedestrian BridgePhase 4 installs a lightweight, metal, temporary pedestrian walkway between the newnorthbound platform and the existing northbound platform portion of the new centerplatform. The temporary walkway bridge will span over New Tracks 1 and 2. In addition,this phase constructs the sidewalk/walkway located south of the existing station facilitythat would connect with the temporary pedestrian walkway. The temporary pedestrianwalkway bridge will be able to be lifted, removed and replaced so that construction and railvehicles can access the trackway area.

During this phase, existing Platforms 1 and 2 remain in operation. Service would bemaintained on all existing tracks.

Construction Phase 5 Platform 2 ExtensionPhase 5 includes demolishing and removing the existing stair towers, the existingpedestrian bridge between the existing northbound and southbound platforms, and theexisting station facility. This phase:

x Constructs storm drainage, utilities, sub-ballast, ballast, rail at New Track 1 and NewTrack 2, where the existing station facility/east stair tower was removed

x Constructs the remaining section of the new northbound platform where the existingstation facility was removed

x Constructs the southern stair and escalator to the new pedestrian bridge/walkway alongthe new northbound platform

x Completes construction of the catenary and systems to allow New Track 1 to be placedin service

During this phase, existing Platforms 1 and 2 remain in operation. Service would bemaintained on all existing tracks.

Construction Phase 6 Open New Track 1 and New Northbound PlatformPhase 6 removes the metal, temporary pedestrian walkway and opens the new northboundplatform and New Track 1 to rail service and closes existing Track 1. During this phase ofconstruction, three tracks remain in service including New Track 1 (with platform), ExistingTrack 2 (without platform), and Existing Track 3/New Track 4 (with platform).

Construction Phase 7 Center Platform Connection to Pedestrian BridgePhase 7 includes constructing the center platform connection to the new pedestrian bridgeincluding stairs, elevators and escalators. It completes the eastern portion of the new centerplatform and removes the southern portion of the existing northbound platform. Duringthis phase, Platforms 1 and 3 would remain in operation, and existing Tracks 2 and 3 andNew Track 1 would be in service.

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Construction Phase 8 Open New Track 2Phase 8 does not involve construction but opens New Track 2 to rail service (using theeastern portion of the center platform) and closes Existing Track 2.

Construction Phase 9 Complete Work on West Side of Center PlatformPhase 9 completes the remaining work at the west side of the new center platform. NewTrack 1, New Track 2, and Existing Track 3/New Track 4 are in service (each with aplatform).

Construction Phase 10 Open New Track 2Phase 10 opens New Track 3 to rail service once the center platform work is complete andall four tracks and associated systems are installed and tested. All four tracks on the NECfrom Bridge Interlocking to Grove Interlocking, and all three BWI Rail Station platforms,will be open for rail service.

C.3 RAILROAD AND HIGHWAY STRUCTURES

During construction of the proposed structures for the Herbert Run Bridge and the PatapscoRiver Bridge, and the proposed expansion of the Furnace Road Bridge, individual rail trackswould have to be selectively closed to train traffic during a part of the construction. Aminimum of two active tracks would be maintained although speed restrictions may benecessary. The installation of an independent parallel structure to accommodate the fourthtrack over the Herbert Run Bridge would create minimum disruption from constructionactivities. The new structure, constructed at a similar elevation as the existing structure,would require a design waiver as the construction of the new structure would occur in the100-year floodplain.

While expected to require careful construction planning, the distance between the existingbridge and the new major multi-span structure over the Patapsco River allows minimalimpact on existing train service. The construction of the proposed extension of thepedestrian underpass at MP 110.12 depends on the sequence of construction for the tracks.

Since the existing Reece Road Bridge would not accommodate the proposed additional trackunderneath, it requires the construction of a new bridge over Reece Road. Due to heavytraffic volumes, the roadway cannot be temporarily closed during construction and a detouris not cost effective. In order to maintain traffic in both directions, a new bridge over ReeceRoad is proposed just north of the existing overpass bridge.