Case Studies

Case Studies

Work that earned its place on the next contract.

Five representative engagements across train protection, transport networks, passenger experience, bridge relocations, and traction-power infrastructure.

GLTPS and TPS, Train Protection Systems

Signal · train protection · cutover

Engineering support for Green Line Train Protection System (GLTPS) and wider TPS programs — covering onboard/wayside interfaces, interlocking updates, and test-and-cutover planning.

Challenge

Legacy signalling had to coexist with modern TPS equipment during the phased cutover window. Interfaces between CBTC/TPS logic, interlockings, and vehicle onboard units required careful verification with zero tolerance for misroutes or missed enforcement points.

Approach

Produced wayside drawings, interface documentation, and cutover checklists. Reviewed vendor data for enforcement points, gradient, and timing. Supported factory and site acceptance testing (FAT/SAT) and night-window cutovers with rollback plans for each shift.

Outcome

Supported phased cutovers with signal-test failures trending toward zero and acceptance milestones hit on plan.

Scope

Wayside drawings · interface review · FAT/SAT support · cutover planning · night-window execution · punch-list closeout.

Technology stack

CBTC / TPSInterlocking logicOnboard/wayside interfacesFAT & SATSignalling drawings

Connection Oriented Ethernet, Phase 3C

Transport network · carrier-ethernet · modernization

Design and field support for a Connection Oriented Ethernet (COE) transport build-out — the Phase 3C extension across stations, yards, and control centers.

Challenge

Transit operations depend on deterministic, protected transport paths. COE had to extend into new buildings without disrupting running services that share the backbone — with strict latency, jitter, and path-protection requirements.

Approach

Produced route design, fiber and splice plans, MEF service configurations, and test procedures. Coordinated with existing active-network teams on IP/MPLS hand-offs and bandwidth allocations. Provided OTDR and service-turn-up evidence per circuit.

Outcome

New COE segments turned up with protected-path failover verified and no measurable impact to adjacent running services.

Scope

Transport design · fiber / splice plans · MEF service configs · OTDR certification · turn-up testing · as-built drawings.

Technology stack

Carrier Ethernet / MEFIP / MPLSSingle-mode fiberOTDRPath protection

Design-Build, Passenger Experience

Station modernization · PA/VA · passenger information

Design-build delivery of passenger-experience systems across multiple stations — PA/VA, passenger information displays, wayfinding, CCTV, and access-control integrated under a single delivery program.

Challenge

Coordinating active-revenue stations with multiple trades (MEP, comms, security) while keeping platforms open and ADA compliance intact. Interfaces with existing SCADA, PIS head-ends, and central monitoring required careful cutover handling.

Approach

Delivered single-source design, procurement, and commissioning. Ran BIM coordination across trades to resolve clashes early. Field-tested PA intelligibility, display brightness/legibility, and end-to-end message paths before each station handover.

Outcome

Stations turned over on-schedule with passenger-information uptime targets met and post-handover defect lists minimal.

Scope

Design-build delivery · BIM coordination · PA/VA · PIS displays · CCTV · access-control · testing & handover.

Technology stack

PA/VAPIS displaysIP CCTVAccess-controlRevit / BIMSCADA interfaces

Connecticut River Bridge, MB 106.89

Bridge relocation · fiber & control-systems transfer

Engineering support for the Connecticut River Bridge program at milepost 106.89 — transferring critical signal, communications, and control-system infrastructure onto the replacement structure.

Challenge

Legacy duct bank, fiber runs, and signal house feeds were embedded in the existing bridge. Cutover had to stage around train windows, marine conditions, and a tight maintenance envelope — all while keeping redundancy during the swing.

Approach

Sequenced fiber-route design, conduit bills-of-material, splice plans, and temporary ring paths. Coordinated with structural, track, and signal disciplines to phase lifts and pulls during allowable outages. Delivered red-line as-builts per span.

Outcome

Zero service outages attributable to the relocation; all fiber pairs OTDR-certified and witnessed on site.

Scope

Route design · splice & test · duct-bank coordination · phased cutover plan · as-builts.

Technology stack

Single-mode fiberOTDRSCADA feedsBICSI-aligned OSPDuct-bank coord

Rehabilitation of 5 Circuit Breaker Houses

Traction power · switchgear · protection coordination

Lifecycle rehabilitation of five traction-power circuit breaker houses (CBH) — replacing aged switchgear, re-coordinating protection, and bringing HVAC, lighting, and grounding current to code.

Challenge

Each CBH had to be taken out of service on a rolling window. Protection settings and interlocks required re-coordination with adjacent substations; legacy drawings were incomplete; and existing enclosures imposed dimensional constraints on modern gear.

Approach

Produced field-verified MEP drawings, load calcs, short-circuit and coordination study, revised interlock schemes, and a phased cutover plan per house. Coordinated with power, signal, and comms to protect dependent feeds during each swap.

Outcome

All five houses modernized on schedule with protection re-coordinated and no misoperations during commissioning.

Scope

MEP design · coordination study · gear procurement support · commissioning · as-built drawings.

Technology stack

MV switchgearProtection relayingArc-flash studyHVAC / lightingGrounding & bonding
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