Movable railroad bridges, consisting of lift, bascule, or swing bridges have been used by American rail tracks that cross usable waterways for over a century. Although custom made, movable bridges share many common components and designs. Most of them use weight bearing towers for the movable span using electric or electro-hydraulic systems lift and/or rotate these movable spans. Automated locks hold the bridge in place as soon as the movement stops. The bridge operation, train and ship signaling systems work in synchrony for trains and waterway traffic to be granted safe passage with minimal delay. This synchrony is maintained by using custom-made control systems using Programmable Logic Controllers (PLCs) or Field Programmable Gate Arrays (FPGAs). Controllers located on the movable and the static parts of the bridge communicate using radio and/or wired underwater links sometimes involving marine cables. The primary objective of this paper is to develop a framework to analyze the safety and security of the bridge operating systems and their synchronous operations with railway and waterway systems. We do so by modeling the movable physical components and their control system with the interconnected network system and determine the faults and attacks that may affect their operations. Given the prevalence of attacks against PLCs, FPGAs and controllers, we show a generic way to determine the effect of what if scenarios that may arise due to attacks combined with failures using a case study of a swing bridge.

A comprehensive study is needed to address the human behavior at railroad grade crossings. Human behavior at different signs changes and it may lead to crashes. No guidance is provided in the recommendations provided by Manual on Uniform Traffic Control Devices where and when different type of signs and different combination of signs are appropriate. Crashes occur mostly when the drivers try to go through the gate or around the gate when a train is approaching. Drivers come to a complete stop at stop signs and then proceed only if a train is not coming, this may lead to a crash when they cannot accelerate in time to cross the tracks. Yield sign may have better results in this case. Cross-buck signs are same as the yield sign where drivers should slow down, look for the train and then proceed. However, people may tend to proceed without yielding as it is not as common of a sign. Hence we can say driver behavior at specific sign is important for the recommendation or the guideline to install a sign. Adopting a common sign at all grade crossings could provide enhanced consistency and reduce crashes. A literature review was done on human behavior at grade crossings and the crash rate at different types of signs. Driver behavior at the time of the crash for 15 states was studied from the Federal Railroad Administration data by reviewing detailed reasons for every crash. Driver behavior at different types of signs at the time of each crash was studied from the reviewed data and the literature review. Driver behavior at different signs was summarized.

Although accident frequencies at railway grade crossings have shown a decreasing trend over the last two decades (partly due to implemented safety improvements and technological advances), safety at grade crossings is still a major concern since crossing accidents are usually associated with devastating consequences. This paper investigates the effect of various site attributes on railway crossing safety outcomes using recent Canada wide data from a 6-year period (2008–2013). The new data sets allow adjusting previous accident models according to latest circumstances (e.g., vehicles’ improved safety features) affecting safety dynamics at crossings. Employing Bayesian hierarchical models including the non-conventional Poisson-Weibull model, different safety performance functions were separately developed for crossings with the following major warning systems: (1) flashing light and bell (FLB), (2) flashing light, bell, and gate (FLBG), (3) standard reflectorized crossing sign (SRCS), and (4) standard reflectorized crossing sign and stop sign (SRCS & STOP). Among other findings, the results indicated that traffic exposure (product of train and vehicle), number of lanes, whistle prohibition, train speed, and road speed were the most important factors affecting accident frequencies at Canadian railway crossings. It should be also noted that safety performance functions vary, in terms of independent variables and their associated coefficients, between the aforementioned warning devices.

Highly efficient energy transmission between Overhead Catenary System (OCS) and pantograph is paramount for high speed railway lines. However this is not usually considered relevant for low speed railway lines. But interruptions in mechanical and electrical contact interfaces increase maintenance costs and can lead to EMI problems with its surrounding environment. In order to avoid this, OCS systems are carefully designed using complex programs for calculation of pantograph/OCS interaction and compared with registered data. This means that it is necessary to invest valuable resources (time and money) to design a proper OCS. At the end of the day, in order to obtain full benefits of a well designed OCS, both careful calculation and installation of all the elements of the system are a must. If no balance between design, calculation and installation is achieved, the overall procedure can present cost ineffectiveness due to wrong or careless installation. The first step of a proper OCS installation process is taking into account all the geometrical and mechanical characteristics and restrictions of the system (maximum and minimum span lengths, slopes, cants, etc.) as well as the relative position of masts, portal structures and head spans to the track. The forces applied by the conductors to each mast and cantilever are established bearing all these data into account. Cantilevers are calculated using these efforts as an input data together with all the geometrical restrictions that the system imposes, thus obtaining their complete geometry and the stresses and strains that they will have to support. These stresses and strains are compared to different standards as well as to rate and calculate masts and foundations. The geometric parameters of the cantilevers are used to prefabricate these elements in order to speed the installation process and to avoid onsite installation errors. A precise calculation process is needed to assure that the contact wire is in the correct position. That’s why a proper calculation tool is needed. CLARA, is a tool developed to perform geometrical and mechanical calculations of OCS cantilevers and rate both masts and masts foundations. This tool has been designed in AECOM Madrid Transportation Design Center by the authors. It is an IT tool that performs this calculation in a precise and quick manner, taking into account all the necessary input data and determining output data to the required level of detail as presented in this paper. This tool provides useful data to design OCS controlling parameters that are of paramount importance for final OCS behavior. Some of these parameters are usually non-controlled due to onsite installation procedures. The authors believe that the use of this tool avoids recalculation, inefficiencies and systematic errors and hence it provides the basis for a more cost efficient design and building process.

Collisions at grade crossings are often attributed to driver failure to detect warnings, to comprehend their meaning, or to react appropriately. One of the solutions to tackling these problems is the development of various visual signs. We designed three types of visual warnings at virtual grade crossings: a gate with lights and crossbuck, a gate with a crossbuck, and a crossbuck alone. Study 1 shows that vehicle speeds of 18 participants in the period 20 seconds before approaching the crossing (critical zone) decreased in comparison to the baseline (pre-critical zone) for visual warning type 1, a gate with lights. Additionally, participants, who were exposed to a train early in the scenario, showed more defensive driving behaviors than the other case. In study 2, we considered drivers’ eye movement pattern in the pre-critical and the critical zone for 17 participants. Design applications of warnings in vehicles and on roads and further research directions are discussed.

The United States Department of Transportation’s (USDOT) John A. Volpe National Transportation Systems Center (Volpe Center), under the direction of the USDOT Federal Railroad Administration (FRA) Office of Research and Development (R&D), recently completed a study on the use of pavement markings to reduce instances of vehicles stopping on the tracks at grade crossings. Specifically, the study evaluated the effectiveness of pavement markings placed within the dynamic envelope, the region between and immediately adjacent to the tracks at a grade crossing, and new corresponding signage at the Commercial Boulevard grade crossing (ID# 628186E) in Ft. Lauderdale, Florida. The goal of this research study was to gain an understanding of the effect of dynamic envelope pavement markings and accompanying signage on driver’s not stopping while traversing the tracks. The addition of the dynamic envelope markings and signage is intended to make this area more pronounced, resulting in fewer motorists entering the dynamic envelope if they are unable to exit the other side. Researchers coded driver stopping behavior at this crossing before and after the surface treatments were installed. Vehicles were coded as having stopped in one of four zones: behind the stop line and gate arm (Zone 1), past the stop line but before the tracks (Zone 2), on the tracks (Zone 3), or immediately after the tracks (Zone 4). Stopping in Zone 3 is considered to be the most dangerous behavior that a driver could perform, while stopping in Zone 1 is the safest. The goal of the added markings and signage is to reduce the number of vehicles which come to a stop within the dynamic envelope, thus reducing the possibility that a vehicle is present on the tracks when a train approaches resulting in a collision. The addition of the dynamic envelope pavement markings and modified signage resulted in a statistically significant change in driver stopping behavior. Specifically, the pavement markings and signage reduced the proportion of vehicles that stopped in Zone 3, resulting in a 45% reduction in vehicles stopped in Zone 3 for eastbound vehicles and 14% for westbound vehicles. They also increased the proportion of vehicles stopping in Zone 1, which is the safest behavior a driver can perform (9% increase for eastbound and 6% increase for westbound). Additionally, fewer vehicles were found to stop in both Zone 2 and Zone 4, which are both moderately dangerous. Based on these results, the Florida Department of Transportation is exploring the use of this safety treatment at additional grade crossings with a high risk for unsafe vehicle stopping behavior.

Railroads are increasingly using Communication-Based Train Control (CBTC) technology to improve service capacity and operating efficiency. CBTC is a mission-critical system under which train monitoring and train control are integrated into a single unified system through data links between vehicles, central processors, and wayside equipment. Radio over fiber technology provides a flexible and efficient solution for the Data Communication System (DCS) which needs to ensure integrity and reliability of message delivery in a transparent manner for the train control functions. A Security Device (SD) is defined as a network entity located between the railroad administration’s (the customer) trusted wired network and the non-trusted portion of the DCS network including the radio-based segment, which runs on a customized piece of hardware with a secure operating system and provides secure gateway functionality. This paper puts forward a network architecture and SD software platform design which meets the requirements of a typical CBTC system. The IPSEC protocol used by the SD for data protection renders authentication service through X.509 certificates. A network setup is put together as the proof-of-concept for the presented design proposal and performance assessment is conducted through experimental studies.

Real-time monitoring of various components of a railcar such as wheel bearing temperature, brake line status, integrity of transported goods and many more has become a key focus area of research for the North American freight railroad industry. The ability for timely detection of abnormalities and impending failures prevents costly accidents, the potential loss of life and damage to the environment. Monitoring also increases overall operational efficiency, reliability and safety of freight railroads. Wireless Sensor Networks (WSN) are an obvious choice for implementing such a monitoring scheme. The accumulated data from various sensors distributed throughout each railcar along the length of the train is transmitted wirelessly using multi-hop transmissions to the locomotive for alerting and monitoring. From there, this information is also transmitted to dispatch centers for further analysis and recording. ZigBee technology based on the IEEE 802.15.4 standard is a popular choice among WSN communication protocols, owing to its low cost and low power requirements. ZigBee performance degrades severely in the long chain-like topology characteristic of the railroad application environment. This effectively disqualifies ZigBee as a candidate technology for such railcar monitoring deployments. To overcome these issues with ZigBee deployments for freight train monitoring we developed our Hybrid Technology Networking (HTN) approach [5–7]. HTN leverages both ZigBee and Wi-Fi communication to achieve reliable communication along an entire freight train. Railcar monitoring nodes are grouped into smaller clusters, within which we utilize ZigBee for its low-power operation and report to each cluster’s gateway node. The gateway nodes of all the clusters on a train communicate using Wi-Fi, to benefit from the high throughput and long communication range. This tiered architecture also results in a drastic reduction in overall hop count for end-to-end communication. In this paper we present HTNMote, a hardware platform that we are developing and employing for real-world evaluation of the HTN protocol. We also present results from our field tests of the HTNMotes at the Transportation Technology Center (TTCI) facility in Pueblo, Colorado, operated by the US Association of American Railroads (AAR). The results show that the use of HTN improves performance of the network by at least an order of magnitude compared to a ZigBee-only network. This paper details the design of our HTNMote platform, present the test setup and results, as well as conduct an in-depth analysis of the obtained results as they relate to railroad operations.

The Insulated Gate Bipolar Transistors (IGBT) are widely used in high power converters. Definite advantages of IGBT rectifiers (also called PWM rectifiers) are: zero reactive power, low harmonics, and inherent power recuperation capability. However stationary traction rectifiers are built with either thyristors or diodes, not with IGBTs. The paper compares IGBT and thyristor rectifiers and analyzes the factors precluding the use of IGBT rectifiers at traction power substations.

Traditional Wireless Sensor Network (WSN) solutions have been deemed insufficient to address the requirements of freight railroad companies to implement real-time monitoring and control of their trains, tracks and wayside equipment. With only ZigBee-based elements, the transmission capabilities of WSN devices are limited in terms of coverage range and throughput. This leads to severe delay and congestion in the network, particularly in railroad scenarios that usually require the nodes to be arranged in linear chain-like topology. In such a multi-hop topology to communicate from one end of a train to the locomotive — and due to ZigBee’s limited communication range — data needs to be transmitted using a very high number of hops and thus generates long delays and congestion problems. To overcome this drawback, we have proposed a heterogeneous multi-hop networking approach called “Hybrid Technology Networking” (HTN). In HTN we combined Wireless Local Area Network (WLAN) technologies like WiFi, which provide improved communication range and higher data rates, with low-power communication technologies like ZigBee. This significantly reduces the number of hops required to deliver data across the network and hence solves the issues of delay and congestion, while also achieving superior enery efficiency and network lifetime. The sensor nodes are logically divided into clusters and each cluster has a WiFi “gateway”. All intra-cluster communication is achieved via IEEE 802.15.4 and ZigBee protocols, while all inter-cluster communication utilizes WiFi protocol standards. To implement our proposed technology in railroad networks, we are designing hardware prototypes and simulation models to evaluate the functionality and performance of our HTN solution, which is designed around a dual network stack design governed by the HTN protocol. This ensures full compliance with IEEE and industry communication protocols for interoperability. Since no simulation tools that seamlessly combine both WSN and WLAN technologies in a single module exist, we wrote our own simulation environment using OPNET. In this paper, we have provided information of implementing the HTN protocol in OPNET and the simulation results for different scenarios relevant to railroad operations. These results will demonstrate the efficacy of our proposed system as well as provide the baseline data for testing the hardware devices in live networks. Under simulated traffic and channel conditions and device configurations, we observed a decrease of 77.27% in end-to-end delay and an increase of 69.70% in received data volume when using HTN compared to ZigBee-only multi-hop networks, simulated over 14 railcars in railroad-relevant scenarios.

The San Pedro Bay Ports of Long Beach and Los Angeles continue to provide vital rail connections to the rest of the country. The Rail Enhancement Program sets forth the rail improvements necessary to maintain performance as cargo volumes grow through the year 2035. Implementation of the Rail Enhancement Program has faced hurdles including environmental permitting, funding and competing stakeholder concerns. Cargo growth eased in the years approaching 2010, but the timing of proposed improvements to the rail infrastructure remains critical and challenging. The Rail Enhancement Program is the result of work over the past ten years. Conditions affecting the program have continued to change since the original Rail Master Planning Study of 2000. Updates to the Master Plan have been performed in 2005 and 2010. These documents provide analyses and recommendations for rail improvements to maintain adequate rail service on the Alameda Corridor and through the Port to its rail yards. In developing the Rail Enhancement Program, simulation is used to understand the impacts of increasing cargo volumes on the rail system and to investigate infrastructure and operating improvements required to address deficiencies and to determine improvements to efficiently handle projected traffic. This paper describes the development process with a summary of the analysis methods, resulting proposed rail projects, implementation process and current status of implementation. The steps of the rail system development process include the following: • Evaluation of existing and proposed rail operations; • Conceptual design of over forty potential rail improvement projects; • Analysis of the capacity of existing and proposed facilities; • Scheduling of project development to meet demand; • Estimation of environmental, community and regional impacts and benefits; • Determination of schedule including environmental permit requirements; • Development of project funding plans; and • Preparation of engineering designs and construction documents. The paper will conclude with a summary of the status of key projects from the Rail Enhancement Program. Implementation of the Rail Enhancement Program has included permitting, funding and design efforts on individual projects. The projects currently under development total $1B out of the overall $2B program. The Rail Enhancement Program provides significant benefits to operating efficiencies, environmental impacts and economic impacts. Implementation has been a challenging effort and illustrates the myriad obstacles facing public infrastructure development.

In recent years, image recognition, along with improvements in image processing technology, has become a mainstream method of object inspection. The quality of images directly affects the image-recognition rate. Track monitoring systems play an important role in ensuring safety and preventing derailments of trains, on the basis of the prevailing track conditions. Therefore, the conditions of track systems are very important. In this research, a high-speed frame grabber system is designed. The triggering rate of its line scan camera can be adjusted to match the vehicle speed of the train, so that the pixels per inch of images captured by this camera are fixed. The hardware equipment of the designed system includes a line scan camera, an image acquisition card, artificial lightings, a contrast sensor, and a system on a programmable chip (SOPC) development board. An exposure time control system is designed on the basis of a field-programmable gate array (FPGA) core. The designed system can acquire clear high-speed images while the vehicle speed changes dramatically. The experimental results confirm the feasibility of using line scan cameras for railway vehicles.

The United States Department of Transportation’s (USDOT) Research and Innovative Technology Administration’s John A. Volpe National Transportation Systems Center (Volpe Center), under the direction of the USDOT Federal Railroad Administration (FRA) Office of Research and Development (ORD), conducted a reliability analysis of the four-quadrant gate/vehicle detection equipment installed on the potential high-speed rail (HSR) corridor between Chicago and St Louis. A total of 69 highway-rail grade crossings on a 121-mile (195 km) segment of the 280-mile corridor were equipped with four-quadrant gates and inductive loop vehicle detection technology. This segment, between Mazonia and Springfield Illinois, may eventually carry passenger trains at speeds up to 110 mph (177 km/h), including at many of the highway-rail grade crossings. The analysis was based on maintenance records obtained from the Union Pacific Railroad (UPRR), the owner and operator of the rail line. The results were used to assess the impact of the equipment reliability on the proposed HSR timetable. The Volpe Center study showed that the total average delay to the five scheduled daily high-speed passenger roundtrips was an estimated 10.5 minutes, or approximately one minute per train. Overall, extensive analysis of the trouble ticket data showed that the four-quadrant gate and vehicle detection equipment had a minimal direct impact on the frequency and duration of grade crossing malfunctions.

Track clearance green phases are used at railroad preempted intersections to provide time to clear the railroad tracks of highway vehicles before a train arrives. This paper describes preemption performance measures developed in Indiana that use high resolution, real-time traffic signal event data, and a gate-down confirmation circuit at an active railroad crossing. These performance measures are used to quantitatively assess the synchronization of the track clearance phase with the railroad gate position. Performance measure plots from over 4,000 preemption events over six months are presented. The lessons learned from the assessment of these performance plots are described along with changes made to the test site during the study period. The paper concludes with recommendations for incorporating a highway-railroad synchronization performance measure using the start of railroad active warning time as a surrogate gate-down confirmation circuit.

One of the most important issues for bearing grade steels is the cleanliness of the steel. Impurities present in a cast steel can manifest as hard/brittle inclusions, which are detrimental to a bearing in service. An advanced ultrasonic measurement technique is developed to determine the inclusion size and density in bearing components. Using ultrasonic C-Scan, a map of the inclusions can be developed that pinpoints the worst areas in an entire cone or cup section nondestructively. A threshold is developed for determining good or bad locations so that specific gate settings can parse those discontinuities considered to be detrimental to rolling contact performance. In addition, multiple transducer sizes and frequencies are investigated to determine an optimized scanning configuration. This protocol can then be adapted to perform quality control specific scans capable of investigating numerous parts and determining a failure rate using the rejection criteria.

This paper presents the computational fluid dynamics (CFD) modeling to study the effect of intake port bend angle on the flow field inside the cylinder of a direct injection (DI) diesel engine under motoring conditions. The flow characteristics of the engine are investigated under transient conditions. A single cylinder DI diesel engine with two direct intake ports whose outlet is tangential to the wall of the cylinder and two exhaust ports has been taken up for the study. Effect of intake port bend angle (20°, 30°, and 40°) on the flow field inside the cylinder has been investigated at an engine speed of 1000 rpm. The pre-processor GAMBIT is used for model preparation and commercial computational fluid dynamics code STAR-CD has been used for solution of governing equations and post processing the results. CFD results during both intake and compression strokes have been compared with experimental results of Payri et-al [7, 8]. The predicted swirl ratio, radial velocity and turbulent intensity variations at different crank angles and at different locations are discussed. Distribution of velocity and turbulence intensity inside the cylinder is also discussed. It is observed that the intake ports with 20° bend angle produce maximum swirl and also results in a slight decrease in volumetric efficiency compared to intake ports with 30° and 40° bend angles and there is no appreciable variation in turbulent intensity. Hence, for the better performance of a DI diesel engine, it is concluded that the intake ports with 20° bend angle is most appropriate and CFD is an effective design tool to develop more efficient DI diesel engines.

This paper describes a numerical study on fuel-air mixing and combustion in a direct injection stratified charge spark ignition engine. The in-cylinder flow, fuel-air mixing and combustion characteristics are investigated in a single cylinder, four-valve, four stoke, direct injection SI engine with pent-roof head and reverse tumble ports. The engine combustion chamber had the side mounted injector and spark plug at the center of pent-roof. Wall guided fuel-air mixing scheme has been adopted. The pre processor code Es-ice, used for dynamic grid generation preparation including description of piston and valve motion. Commercial computational fluid dynamics code Star-CD is used for solving governing equations and post processing of results. Combustion in the present study is simulated using Extended Coherent Flame Model-3z (ECFM-3Z). This model is based on a flame surface density transport equation that can describe inhomogeneous turbulent premixed combustion. In the present study, engine simulations has been carried out from 370 CAD before TDC and upto 90 CAD aTDC. The process includes the closing of the exhaust valves, the whole intake stroke, injection, combustion, and part of expansion. Three different injection timings are simulated viz. 55, 60 and 65 CAD bTDC. For validation of the code predicted results are compared with experimental results available in the literature. It is observed that, injection timing has an important role in mixture preparation and distribution around the spark plug. Hence, for the better combustion characteristics start of injection timing should be optimized.

In this paper we present the Taipei Rapid Transit System program to replace the original DC motor drive of the Medium Capacity Transit System (MCTS) trains with modern IGBT circuitry. The MCTS fleet employed traction power circuit designed in 1980’s, which soon suffered from high failure rate long before midlife overhaul. With modern power electronics technology we replace the cumbersome drive circuitry for current-controlled transistors by simple and straightforward gate drive circuit for voltage-controlled IGBTs. Also the large number of discrete components found in the original board is now replaced by modules and ICs, improving service reliability and life expectancy.