Rail (passenger and freight) industry has been under pressure to tackle climate change, local and noise emissions. The current available powertrain technologies to reach the reduced greenhouse (GHG) and zero local emissions demands are electric (fed from the power grid), battery and fuel cell. However, the associated infrastructure costs (electrical equipments and the required overhead catenary infrastructure) have limited the electric option to heavy loaded corridors. Battery electric powered rail vehicles could be another potential option, but their system recharging requirements might significantly limit the system’s availability, thus, impacting the rail vehicle’s on-the-job performance. The recent breakthrough of fuel cell technology in the heavy duty road industry (mainly transit buses), allied with its operational flexibility and environmental performance has opened the way for this groundbreaking technology in the rail industry. Fuel cells generate electricity onboard, using hydrogen or hydrogen rich hydrocarbon fuels. Electricity is, then, stored in batteries or fed directly into a rail vehicle’s high voltage propulsion system. From an operational perspective, fuel cell powered rail vehicles might replace diesel ones in a one-to-one relationship, with the same range and running times, and a more efficient and less noisy powertrain. Moreover, the on-site refilling station is the only additional infrastructure element required, compared to diesel rail vehicle baselines. In short, fuel cell technology might offer a long term local zero emission alternative, fast refuelling (like diesel), flexibility, with self-electrification, integration with a renewable energy source and a quiet operation. Given their outstanding operational and environmental features, several rail market niches might be addressed by the fuel cell technology: i) light rail and trams in urban environments; ii) commuter and regional trains operating on non electrified tracks; iii) shunt or switch locomotives in rail yards (generally located on central portions of large cities or at the crossroads of major rail distribution hubs); iv) underground mining locomotives, and v) line haul locomotives. Since 2002, there has been an intense activity in the global development of fuel cell technology for the rail industry for both passenger and freight markets. This work is supposed to present, based on the compilation of information from a multitude of acknowledged sources, a review of fuel cell rail technology, followed by an overview of fuel cell rail experiences and feasibility studies, highlighting their main outcomes, as well as fuel cell technology potential to offer lower operational costs (fuel and maintenance) and improved performance for the rail industry.

Cab signaling enforces the separation between trains as well as enforcing trains to reduce speed as the train approaches signals displaying STOP. Cab signaling allow for and provides a safe way to eliminate the number of wayside automatic signals while the number of controlled speeds can be increased. Light Rail Transit (LRT) systems today are built completely with cab signaling and only fixed wayside signals are placed at interlockings for routing information. Experimental cab signaling systems began in the United States in the 1920s, kicked off by the Interstate Commerce Commission (ICC) ruling that required some form of Automatic Train Control (ATC) be installed on one passenger division by 1925. This paper will begin with examining the initial ATC designs (intermediate and continuous), the first experimental installations, the testing challenges and the overall enhancements that pioneered cab signaling systems in the US. The focus will include the teaming of the Pennsylvania Railroad with Union Switch and Signal (US&S) to develop, build and successfully test the continuous cab signaling system which later became the de facto standard. The early systems implemented used two (2) speeds, methods on adding a third speed and how the system became integrated with the existing automatic block signaling. How Pennsylvania Railroad (currently Amtrak) is still using the technology that started 100 years ago on the North East Corridor. It will also introduce how Light Rail systems operate on speed commands using cab codes.

American Railroads are planning to complete implementation of their Positive Train Control (PTC) systems by 2020 with the primary safety objectives of avoiding inter-train collisions, train derailments and ensuring railroad worker safety. Under published I-ETMS specifications, the onboard unit (OBU) communicates with two networks; (1) the Signaling network that conveys track warrants to occupy blocks etc. and (2) the Wayside Interface Unit (WIU) network, a sensor network situated on tracks to gather navigational information. These include the status of rail infrastructure (such as switches) and any operational hazards that may affect the intended train path. In order to facilitate timely delivery of messages, PTC systems will have a reliable radio network operating in the reserved 220MHz spectrum, although the PTC system itself is designed to be a real-time fail safe distributed control systems. Both the signaling and the WIUs communicate their information (track warrants, speed restrictions, and Beacon status) using software defined radio networks. Given that PTC systems are controlled by radio networks, they are subjected to cyber-attacks. We show a design and a prototype implementation of a PTC Cyber Situational awareness system that gathers information from WIU devices and Locomotives for the use of rail operators. In order to do so, we designed secure IDS components to reside on the On Board Units (OBU), signaling points (SP) and the WIUs that gather real-time status information and share them with the Back Office system to provide the cyber-security health of the communication fabric. Our system is able to detect and share information about command replay, hash breaking guessing and message corruption attacks.

Rail switches are critical infrastructure components of a railroad network, that must maintain high-levels of reliable operation. Given the vast number and variety of switches that can exist across a rail network, there is an immediate need for robust automated methods of detecting switch degradations and failures without expensive add-on equipment. In this work, we explore two recent machine learning frameworks for classifying various switch degradation indicators: (1) a featureless recurrent neural network called a Long Short-Term Memory (LSTM) architecture, and (2), the Deep Wavelet Scattering Transform (DWST), which produces features that are locally time invariant and stable to time-warping deformations. We describe both methods as they apply to rail switch monitoring and demonstrate their feasibility on a dataset captured under the service conditions by Alstom Corporation. For multiple categories of degradation types, the baseline models consistently achieve near-perfect accuracies and are competitive with the manual analysis conducted by human switch-maintenance experts.

Several Authorities are procuring Hybrid Streetcars with OESS. The energy storage system needs to be protected from ground faults, external and internal to the vehicle. A Hybrid Streetcar has an OESS consisting of either Lithium Batteries or super capacitors, with an OESS converter connected to, or integrated with, the Traction Inverter. During a ground fault of the high voltage circuit, the freewheeling diode in an OESS charger creates a fault path between the energy storage elements and ground. Typical vehicle designs use a fuse for catastrophic protection, depending on the vehicle ground fault scheme for detection and protection. The vehicle’s primary ground fault detection device is an HSCB, usually connected between the shop switch and traction inverter; the auxiliary inverter is typically protected using a fuse. An HSCB is able to protect typical fault currents seen within the traction chain, but is not designed for OESS fault currents. If a fault occurs the fuse for the catastrophic protection of the OESS will blow before the HSCB will trip, potentially damaging equipment, making the vehicle inoperable. This paper compares alternative methods which can be deployed to detect and protect the OESS from a ground fault.

American Railroads are planning to complete implementing their Positive Train Control (PTC) systems by 2020. Safety objectives of PTC are to avoid inter-train collisions, train derailments and ensuring railroad worker safety. Under published specifications of I-ETMS (the PTC system developed by Class I freight railroads), the on-board PTC controller communicates with two networks; namely, the Signaling network and the Wayside Interface Unit network to gather navigational information such as the positions of other trains, the status of critical infrastructure (such as switches) and any hazardous conditions that may affect the train path. By design, PTC systems are predicated on having a reliable radio network operating in reserved radio spectrum, although the PTC system itself is designed to be a real-time fail safe distributed control systems. Secure Intelligent Radio for Trains (SIRT) is an intelligent radio that is customized to train operations with the aim of improving the reliability and security of the radio communication network. SIRT has two tiers. The upper tier has the Master Cognitive Engine (MCE) which communicates with other SIRT nodes to obtain signaling and wayside device information. To do so, the MCE communicates with cognitive engines at the lower tier of SIRT; namely the Cryptographic Cognitive Engine (CCE) (that provide cryptographic security and threat detection) and the Spectrum Management Cognitive Engine (SCE) (that uses spectrum monitoring, frequency hopping and adaptive modulation to ensure the reliability of the radio communication medium). We presented the architecture and the prototype development of the CCE in [1]. This paper presents the design of the MCE and the SCE. We are currently developing a prototype of the SCE and the MCE and testing the performance of our cognitive radio system under varying radio noise conditions. Our experiments show that SIRT dynamically switches modulation schemes in response to radio noise and switches channels in response to channel jamming.

The New York City Transit (NYCT) Signal Modernization Program has been ongoing since the mid-1990s. The current phase of modernization involves the procurement of Solid State Interlocking (SSI) systems that are designed to replace relay-based interlockings. SSI procurement has necessitated significant adjustments to NYCT’s system deployment processes, most notably in the areas of design, implementation, test, maintenance, and safety certification. NYCT has successfully met the challenge of applying the updated deployment processes to multiple, concurrent system procurements. The most fundamental change to the NYCT procurement approach required a shift from the traditional design-build model of acquisition for relay-based systems to a software-based development lifecycle for SSIs. The relay-based Interlocking systems’ design-build model has traditionally involved the realization of complex relay logic with well-known hardware components such as relays, trip-stops, signals and switch machines. The SSI systems’ software model however requires additional consideration of software and hardware development phases, such as designated in the V-lifecycle. V-model phases include requirement, design, implementation, and test. For SSI systems, NYCT adopted a “double” V-Life cycle approach, one V for the supplier’s SSI hardware and software (executive) platform, and one V for the SSI application (site-specific field) logic. At NYCT, the first V is dedicated to the suppliers’ executive platform. Hardware and software comprising the supplier platform are verified to meet safety and performance requirements. Safety analyses such as Fault Tree Analysis, Failure Modes and Effects Analysis, Timing Analysis, and Hazard Analysis are generated by SSI suppliers. System Safety Concepts, e.g., Numerical Assurance, Checked Redundancy, Intrinsic Fail-Safety are also assessed. NYCT’s second V is dedicated to the application software, i.e., the site-specific relay-based logic, which is implemented as Boolean logic within the SSI. For the Booleans, the process of traditional circuit checking is supplemented by Model Checking, wherein NYCT General Safety Properties are used to verify the site-specific logic. Model Checking provides assurance that safety properties are met throughout the entire interlocking design, for every system state, and does not rely on a manual review process. This paper will focus on the benefits NYCT has realized as a result of adopting Model Checking as a requirement for safety certification, along with an overview of the NYCT SSI safety certification process.

Three-point contact occurs in curving and transfer of a wheelset over switches and turnouts. In this study, an approach is presented that enforces three-point contact between a wheelset and a rail. This is accomplished by placing the wheelset over the track by setting the wheelset position parameters. Then, the location of all common normal are computed. Next, three common normal with shortest length are used to set up the non-penetrating constraint equations in track coordinate system. This led to nine algebraic equations whose Jacobean can be represented by block matrices. A Newton iterate based on these block matrices are used to compute the location of the three contact points. Several numerical examples are presented to verify the accuracy of the approach.

Positive Train Controller (PTC) is a communication based system designed to enforce PTC safety objectives for trains such as train-to-train collisions, train derailments, and ensure railroad worker safety. Existing PTC designs consider risks due to operational environment such as location of other trains, switches, and speed limits. We propose to enhance PTC by using a multi-tiered cognitive radio network that considers multiple risks such as those due to bandwidth congestion, packet length limitations, propagation losses, detectable exploitation of Software Defined Radio vulnerabilities, and protocol vulnerabilities. Radios operating at PTC nodes (such as train, WIU and Base station) is equipped with a cognitive layer, which communicates with other nodes to create a cognitive radio network. The proposed network as a whole strives to provide spectrum management and security for the radio communication system, which can enhance the PTC functionality. Each cognitive radio in our proposed network consists of multiple tiers. The upper tier consists of a master cognitive engine that holistically evaluates the operational risks of the network and acts to mitigate them using the lower tiers. The lower tier (immediate slave tier to the master) consists of sub cognitive engines for cryptographic operations and spectrum management. The traditional PTC protocol is implemented at a lower tier module that interface with the master Cognitive Engine (CE). The master-slave communications within one radio is implemented using middleware. The proposed cognitive radio network can be modeled as a cyber-physical system by incorporating train movement dynamics, radio transmission characteristics and cryptographical computations, thereby constituting a distributed system of communicating hybrid automatons. This design enables us to verify safety and the security of the system using formal methods, which constitutes our ongoing work. We also discuss potential issues such as FRA mandated safety cases that needs to be addressed if the proposed features are to be added to the PTC systems.

Contact between the wheel and rail can have a significant effect on the dynamics of vehicle/track interaction models. Many existing rail surface models rely on curve based geometry which may lead to some geometric inaccuracy in the case of variable cross-section rails. This investigation will focus on the development of a new spatial geometry based rail surface description which reduces this geometric inaccuracy. It has been shown in literature that certain CAD geometry types, such as B-Spline curves and surfaces, may be converted to equivalent absolute nodal coordinate formulation (ANCF) finite elements without a loss of geometric accuracy. To this end, a new ANCF surface description of variable cross-section rails is developed. This investigation also demonstrates the feasibility of using, in the future, 3D surface scanning techniques as well as profile curve measurements to develop a rail surface geometry model using the new ANCF surface which can be systematically integrated with complex multibody system (MBS) models. A realistic railroad vehicle example of a turnout, which includes variable cross-section rails, is tested for the case of the new ANCF surface. A study of the numerical results reveals the benefits of using the ANCF surface geometry developed in this investigation.

The Los Angeles Metropolitan Transportation Authority (LACMTA), like many other transit agencies throughout the country, is currently addressing the stray current corrosion problems on its rail system. Numerous capital projects have been released by the authority for the rehabilitation of their corroded infrastructures along their right-of-way. In addition, new maintenance procedures have been implemented to minimize corrosion problems to the rail and utility infrastructures located adjacent to the electrified railroad. The corrosion effect on rail infrastructures is often overlooked by most electrified railroad authorities because an immediate corrective response is not necessary for train movement during rail operations. The corrosion process is a natural process that occurs slowly and continuously throughout the life span of all materials, and may be accelerated due to stray currents from the railroad electrification system. Several key locations along the right-of-way have greater impact from stray current corrosion issues: at street crossing due to poor rail insulated boots, switch machines and accumulation of brake dust near passenger platforms. Other significant locations that suffer from stray current effects are overhead and under grade bridges, tunnel structures, rail spikes, fire suppression pipes, sewage pipes and underground feeder cable connections. Moreover, stray current can also cause other vital systems such as signaling systems and communication systems to malfunction. The other aspect of stray current is intentional discharging of stray current into earth ground through Negative Grounding Device (NGD) to maintain negative rail over voltage level for safe operation and reliability of rail service to the public. Typical negative rail voltage with respect to earth ground in operation is over 100VDC which is over the recommended voltage of 50VDC. Corrosion problems can be controlled by the implementation of a cathodic protection system, proper inspection of the running rail, impedance bond connections and proper maintenance of the cathodic protection system and negative grounding devices. The purpose of this paper is to address corrosion issues associated with DC electrified railways, recommend maintenance practices to control stray current sources, recommended maintenance practices for cathodic protection systems and discuss the balancing act to control negative rail over voltage versus intentional discharge of stray current to earth ground.

In this paper we present our study on load power quality characteristics of new trains with switch-type converters using field measurement data. We apply these data to perform power flow and harmonic power flow computations to examine the impacts of new train loads to existing ac traction power network with filters designed for old train loads. Our simulation results show that existing filters can result in over-compensation of reactive power and ineffective filtering of load current harmonic components. It is recommended that filter designs be modified to suit the load power characteristics of new-generation trains.

This paper presents a novel technique that utilizes wavelet analysis to identify and predict the defects in railroad foundations and rails to prevent derailment or other damages. The proposed defect detection algorithm eliminates the use of wheel and/or track monitoring systems, which are expensive and time inefficient. The algorithm has been validated for the rail crack prediction using only vertical accelerometer signal which accurately detects impending rail breakage while distinguishing the signal generated by special track components such as rail joins and switches. Since the algorithm is flexible, further development can be tailored to detect significantly different rail defects such as track shift and other rail foundation defects. The algorithm is further improved by incorporating SIMPACK dynamic simulation to assist classification of the acceleration signatures. The actual data was then compared to simulation in order to validate the effectiveness of the algorithm.

Wheel profile evolution has a large influence on track and wheelset related maintenance costs. It influences important parameters such as equivalent conicity or contact point positioning, which will affect the dynamic behavior of the vehicle, in both tangent track and curve negotiation. High axle loads in freight wagons may increase both the wheel wear and the damage caused by vehicles with both new and already worn profiles. A common profile in Europe is the S1002 profile, developed for rail inclination 1/40. In Sweden rail inclination is 1/30, so contact conditions might not be optimal. The presented work uses Archard’s wear law to analyze the profile wear evolution in a two axle freight vehicle with Unitruck running gear on the Swedish network. This wear calculation methodology has been successfully used to predict uniform wear in passenger vehicles. First, the vehicle model has been optimized in order to improve the speed of the wear simulations. Experimental measurements of wheel profiles have been performed in order to validate the simulations. The conclusion is that the wear methodology successfully used to predict uniform wheel wear in passenger vehicles cannot be directly applied for the calculation of wheel profile evolution in high tonnage freight vehicles. The influence of block brakes or switches and crossings cannot be dismissed when calculating uniform wheel wear in these cases.

The negative return portion of a modern direct current (dc) traction power system, which includes the tracks (the running rails), is normally isolated from earth to the maximum extent practical. The purpose of this isolation is to prevent stray dc currents from flowing through the earth and potentially causing corrosion of nearby metallic infrastructure. The isolation of the tracks from the earth is not perfect. Each track tie and insulated rail fastener assembly can be electrically represented as a resistor of high ohmic value connected between the rails and the earth. With many of these resistors in parallel over miles of track, a distributed “leakage resistance” is established between the rails and earth. For modern dc traction power systems in particular, however, this resistance is high enough for the rails to be considered essentially ungrounded with respect to local electrical ground (earth). The lack of an intentional connection between the tracks and earth allows voltage differences to occur along the rails, and between the rails and nearby structures. These voltage differences are caused by the flow of current through the running rails back to the substations. Since the shells of rail vehicles are typically at the same voltage as the wheels and rails, this voltage difference could be impressed on a passenger entering or exiting a train from a grounded platform. Or they could be impressed on a person walking along the tracks. In the USA, these voltage differences have generally been limited through system design; North American standards for substation grounding are referenced for design purposes, in particular IEEE Standard 80, Guide for Safety in Substation Grounding . In Europe, a standard has been developed specifically to address control of voltages between rails and structures, BS EN 50122-1 (IEC 62128-1), Railway Applications – Fixed Installations – Part 1: Protective Provisions Relating to Electrical Safety and Earthing . Voltage-limiting equipment that can be installed in passenger stations and other accessible locations has been developed in response to the requirements of EN 50122-1. These devices quickly connect the running rails to the station structure to eliminate unsafe voltage differences. If an earth fault occurs (broken catenary conductor falling on the ground, for example), there may not be a low-resistance circuit back to the substation due to the electrical isolation between running rails and earth ground. Without a low-resistance path back to the substation, there may be a resulting low-level short circuit current flow insufficient to operate the substation protective systems. As a result, the area in the vicinity of the fault may potentially be elevated to unsafe voltage levels. Equipment intended to detect this condition and connect the substation negative dc bus to the substation grounding grid is gradually being incorporated into modern North American dc traction power substation design. These devices are known by several names such as “substation grounding contactors”, “automatic grounding switches”, and “negative grounding devices”. Devices built to comply with EN 50122-1 are termed “Voltage Limiting Devices”. EN 50122-1 includes voltage-time curves that dictate the maximum permissible magnitudes and durations for ac and dc voltages; equipment built to EN 50122-1 must clamp the highest voltages in no more than 20 milliseconds. This paper will review current American and European standards and codes for maximum permissible rail voltage on direct current traction power systems. The maximum permissible voltage levels will be explained and compared. The principles of negative grounding device operation and corresponding voltage settings will also be discussed.

North American railways have experienced significant traffic growth over the past 20 years to the point where many lines are at or near capacity. While the current worldwide recession has eased capacity constraints momentarily, the long-term trends are for continued traffic growth. Faced with the prospects of perhaps doubling freight traffic demand in the next 20 years and adding significant passenger traffic, the railroads are developing cost effective ways to increase capacity. Besides constructing additional tracks, improving the performance (i.e., safety, reliability, and service lives) of key track components is expected. Both heavy axle loads (HAL) and high speed rail (HSR) passenger traffic require high quality, durable track. The paper will describe recent work done to improve the dynamic performance and durability of these track components: • Special trackwork. • Rail joints. • Crossties. • Track transitions. For example, turnouts are being developed that can accommodate freight shippers served from mainline track that also carry high speed traffic. These continuous mainline rail switches and frogs allow slow speed diverging operations that will not affect mainline track performance. The paper will also discuss further heavy haul infrastructure research and development needs.

In this paper we present the result of a case study on the switching overvoltage transients of ac electrified railroad trains equipped with switch-type rectifiers in Taiwan Railway Administration (TRA). It was found that new generation of switch-type converters could result in significant over-voltage of magnitude comparable to lightning surge if no proper snubber circuit be used. The switching surge could damage power equipment of nearby trains in the same service zone, as observed in the TRA system. It is recommended that maximum tolerance of switching over-voltage be clearly specified in the procurement phase of new trains with switch-type converters then accurately verified in the commissioning phase to ensure proper preventive measure be installed.

On September 11, 2001, the terrorist attacks that destroyed the World Trade Center (WTC) in Lower Manhattan, New York City, also damaged the Port Authority Trans-Hudson Corp.’s (PATH’s) busiest terminal serving the heart of the thriving downtown financial, commercial, and residential district. The aftermath of the attacks also forced the closure of PATH’s key station at Exchange Place that serves Jersey City, New Jersey’s expanding “Gold Coast” business and residential area. PATH’s more than 260,000 average weekday commuters between New Jersey and New York were affected in some way by these tragic events, and PATH ridership fell sharply during the following months. Among the PATH facilities that were damaged or destroyed at WTC, and in the two Hudson River tubes, and at Exchange Place Station were all of the electrical, power, signal, and communications systems. Recovery and restoration work began immediately, but was hampered by the extensive rescue, recovery, removal, and demolition work at the World Trade site. Broken water lines and fire fighting efforts flooded both river tubes, which were later sealed at Exchange Place to prevent additional potential damage to PATH’s New Jersey facilities. This paper describes PATH’s recovery program to replace the electrical, power, signal, and communications facilities from Exchange Place to the WTC Terminal. A temporary WTC terminal has been built to restore direct service to Lower Manhattan’s financial, business, and residential center as of November 23, 2003. As part of this program, new trackwork was installed to enhance operational flexibility and provide temporary interim service to Exchange Place Station, which reopened June 29, 2003. Capacity expansion provisions were included to allow for future 10-car train operations when a new rail car fleet is procured. Facilities replaced include a new traction power and auxiliary services substation, new cables, ductbanks, new signals and central control system, wayside phones, emergency power removal switches, tunnel lighting, radio antenna, and fiber optics. An accelerated design and construction schedule was followed, using a broad combination of in-house, consulting, and contractor forces.

This paper provides a description of a Collision Avoidance System (CAS) that is being developed by Union Switch & Signal (US&S) for Alaska Railroad Corporation. The CAS performs two main functions: automated traffic planning, and vital collision avoidance. The CAS is being implemented with proven signaling system elements such as the US&S MicroLok ® II and MicroCab ® platforms, a standard computeraided dispatching subsystem, and commercially available communication network elements. This implementation will provide a higher level of safety and performance relative to the manual train control system currently in operation on the Railroad. The safety aspects of the CAS will be proven to be in compliance with the proposed FRA Rule 236 Subpart H requirements.

This paper covers the Advanced Train Control Systems (ATCS) protocol. ATCS is an open standard for Radio Frequency data systems in railroad networks. Currently ATCS is used for functions such as throwing track switches and changing track signals. Vulnerabilities in the ATCS protocol are discussed in this paper, along with a hobbyist program called “ATCS Monitor” that decodes the signals. Finally the paper looks at the current mitigating factors for these vulnerabilities and proposes additional ones.