System Integration on Rail Transit Projects

 

Since dirt roads with horse drawn carriages and wagons were replaced with rails, rail transit systems were built from the top of running rails (TOR) and centerline of rails (COR).  TOR is the interface for rails car vertical clearances with overhead structures, passenger car vestibule interfaces with station platforms.  COR is the interface for horizontal clearance between rail cars and structures along the Right Of Way (ROW.)

Rail transit industry evolved to steel rails and cars with steel wheels and axle sets.  From this foundation, operators continued to integrate technology and raise service standards by adding systems to improve the safety of train operations and comfort in passenger cars and fixed infrastructure.  Each improvement created more interfaces and the need for more extensive testing of interdependent systems assure operation to meet standards.    Some of the interfaces are:

• AC and DC electric motor propulsion and passenger HVAC comfort on rail cars
• 3^rd rail DC power and AC overhead catenary power to support passenger cars
• 110hz Ac powered signal systems for safest movement rail cars
• Communications systems for operations and customer information at stations and on-board rail cars.

As world events affected mankind, safety and security systems were incorporated for surveillance of employees, passengers and other customers in stations, terminals, facilities and passenger cars and monitor environmental conditions in terminals.  

The rail transit industry is always developing improvements for upgrading fixed assets and rolling stock systems.  The more recent improvements include providing real-time status on service on video displays and message signage in passenger cars, stations, and platforms.  Other improvements such as positive train control, and video monitoring of engineer status in the cab of passenger cars and locomotives are still being developed.  

Each subsequent improvement creates more interfaces and the need for more extensive testing of interdependent systems assure operation to meet standards.   

In rail transit – TOR and COR remain a constant datum for the interface between passenger cars and system infrastructure.    It is also a baseline criterion for developing scope, technical criteria, and design, construction and testing requirements for capital projects.   The project scope, execution method, cost and duration are a function of the business case category.  

Common business case categories are stated in the New York MTA Capital Program Plans for planning projects and they are:

• State of Good Repair (SGR) projects renew assets that have surpassed their useful life, to achieve SGR. 
• Normal Replacement (NR) projects renew assets that are nearing the end of their useful life, to preserve SGR
• System Improvement (SI) projects enhance the network, providing new capabilities and a better customer experience  \
• Network Expansion (NE) projects extend the reach of the MTA network, expanding the service offering

Unlike air travel, water travel and roadway travel, the rail transit passenger cars and infrastructure are always physically constrained by the characteristics and features of the fixed assets and the rolling assets.  As a result, the design, construction and testing for commissioning and use of projects require all the parts to be tested together after all tests are completed on individual systems.

Wayside systems and rail car interfaces include:

Track:              Rail gage – distance between rails and switches, COR spacing with adjacent tracks, and TOR and COR clearances with structures along the ROW need to align with spacing of axle wheels sets for movement of rail cars and on-rail vehicles.

Power:             Substation and signal power equipment, positive cables and negative return cables needs to supply adequate power for wayside and rail car propulsion and to supervisory monitoring system, and the 3^rd rail TOR and COR such as height needs to align with rail car contact shoe.

Signals:            Signal generators for coding running rails need to support rail car cab signals, wayside signals for aiding operating engineers in determining and controlling speed, and for correlating track conditions with scheduled train routing.                      

Structures:       Wayside structures need to provide proper vertical - TOR and horizontal – COR clearances for dynamic movements of rail cars at the maximum operating speed for the track geometry and topographic (civil) conditions.

Facilities:         Equipment and tools need to provide TOR and COR clearances matching the outline of rail cars and rail-borne vehicles for inspection, maintenance and repair.

But the linchpin interface for connecting the systems to form a fully integrated and functional transportation system is:

Communications:  

• Radio systems and network coverage throughout the system connecting qualified operating employees at train operation centers and local control towers, on rail cars and on-rail vehicles, and wayside facilities, including interfaces with positive train control.
• Cable network connecting telephone and data lines to substations and motor generators; signal huts, equipment and wayside signals; customer information service displays and signage
• Cable network connecting to traffic safety and security systems, including CCTV and other features for video analytics such as recognition technology for persons, idle packages, vehicle tags and crowding of persons
• Cable network and wifi equipment to connecting business operating systems, fare collection and ticketing systems, and mobile technology systems to customer cellular applications.

The International Council of Systems Engineers (ww.incose.org) describes the integrative approach through the engineering lifecycle as:

The integrative approach has long been used in systems engineering and usually involves either interdisciplinary (e.g.. integrated product teams) or multi-disciplinary (e.g.. joint technical reviews) methods. The integrative approach by itself can be adequate where the situation is not overly complex and there are smaller numbers of stakeholders potentially impacted. The integrative approach can be used when dealing with a highly precedented situation that has been encountered before and a path to the solution can be readily identified and understood (albeit there will still be many challenges along the way, technical and otherwise). The integrative approach includes the traditional multi-disciplinary and inter-disciplinary approaches commonly used in systems engineering practice. The transdisciplinary approach may be needed in unprecedented situations or where there is a significant degree of complexity involved. See Madni (2018).

System Integration Testing (SIT) commences after all the individual systems are tested and commissioned for alone operation.   The integration scope will encompass all wayside and rail cars working together in unison to verify that all systems are operating as designed and in accordance with Owner and regulatory requirements, such as Federal Transit Administration.  

Per Federal Transit Administration (FTA) Oversight Procedure 54:

System Integration Testing SIT validates that all fixed facilities, systems, and equipment perform as intended, both individually and as an overall system when integrated. The process also confirms that all personnel have the management capacity and capability to provide safe and dependable service, and that emergency drills have been completed prior to revenue operations. For a well-managed project, SIT is integrated into the project master schedule with time-phased activities showing the inter-dependencies between various activities and project milestones.

SIT for projects that are State of Good Repair and Normal Replacement (and some System Improvements) may be adequately covered by a series of Factory Acceptance Testing (FAT), and Site Acceptance Testing (SAT), which may include a burn-in period to monitor performance and compatibility.  Most of these type projects use the Owner’s existing and well proven specifications and approved products.  And many railroad systems, such as signals, require extensive pre-testing to support cutovers that are conducted with the system shut down for testing with trains operating without customers to run every possible train route.  As a result, the exposure to risks on these type projects is relatively low impact to the Owner’s existing system and operating plans.  These tests may be sequenced incrementally over several weekend outages to minimize impacts to weekday service plans.

SIT for projects that are System Improvements and Network Expansion, System Integration Testing is larger scope that builds upon FAT and SAT.  These projects can vary from first time applications of new systems or new technology, or are a completely new type infrastructure to the Owner’s existing system or new startup.  Each scenario presents exposure risks on practices and processes for operation, inspection, maintenance and repair.   As a result, SIT will require a larger testing scope.  These type projects have a larger exposure to risks with higher impacts on the commissioning and startup, operating processes, and manpower loading and skills.   This may require longer period of testing to assure all risks are mitigated

SITs will test, measure, analyze and verify compliance to expected results for a comprehensive list conditions that replicate all potential operating scenarios including train routes, train density and passenger car loading.  While dependent on project scope, below is a sample list of SIT test attributes:

Track:              Reliability and durability of switch operations

Power:             Third rail voltage drops and substation/motor generator breaker operation and trip setting

Signals:            Switch point and rod operation, switch position integrity, indications for wayside signal aspects and cab signal speed aspects, and positive train control

Structures:       ROW clearances with dynamic envelopes for rail cars and on-rail vehicles, and operations of vertical transport and building systems

CCTV:    Camera field of view, analytics and indications

Ops Center:     Remote operation of track switches, electrically operated power switches and breakers, camera panning, PA announcements, information message displays, intrusion alarm indications, radio communications with train engineer/conductors, towers, employee facilities, and ROW inspectors and maintenance work crews. 

TIP:    The scope, complexity and duration of SIT is a function of the project classification, scope, division of work between contractors and in-house forces, work conditions and the Owner's experience with similar FTA (government) funded projects.

TIP:    SIT processes, procedures and documentation should be tailored to the Owner's existing organization, quality management system, safety and security program plan and operating plans and procedures.   

TIP:    If the Owner has completed similar projects before, they will be a good source and judge on the SIT completeness and realism of the execution schedule.

TIP:    Owner’s input is essential to assure the SIT is not under-scoped on complex projects or over-scopes on projects that contain well documented and previously used testing processes, procedures and schedules. 

TIP:    SIT schedules need to be consistent with the work conditions in the Contract, which may restrict work hours, require services modifications and shut downs, and need protective services to support the testing.

TIP:    For work performed by in house forces, the SIT, final inspection and determination if the work is safe for service is designated to the on-site qualified and responsible person (s).  The processes, procedures and documentation is well established by the Owner and in compliance with Federal Railroad Administration (government) regulatory requirements for railroad operation.  

For more information, visit:

Procedure 54: https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/OP54%20Readiness%20for%20Revenue%20Operations%20-%20Sept%202015.pdf

Lessons Learned – Sun Rail (New Start)

https://www.transit.dot.gov/regulations-and-guidance/implementation-systems-integration-testing

MTA Capital Program

https://new.mta.info/capital/2020CapitalProgram

International Council for Systems Engineers

www.incose.org