Light Rail Train Research Articles

Steering Mechanism and Capability of Forced Steering Device for Low-Floor Light Rail Train

For 70% low-floor trains on the light rail lines in Changchun, a multi-linkage forced steering device (FSD) is developed aiming at relieving the independently rotating wheelset (IRW) excessive flange wear and improving IRW bogie system running safety on curve line. This FSD employs guiding mode of steering four independently rotating wheels separately in a two-axle bogie, that is, four FSDs are employed to work together to realize the steering of a two-axle bogie. One side of an FSD is connected to the axle of an independently rotating wheel while the other side is attached to the front or rear vehicle body. When train passes through curve, the yaw angle between the IRW bogie and the front or rear carbody drives the linkage system to rotate to guide the independently rotating wheel towards its radial position. The coupled vehicle-track dynamics model for a 6-module single-type low-floor light rail train is developed and simulations of the train passing through tangent and curved tracks with and without FSD proposed are carried out. The results indicate that the FSD can improve the IRW restoring capability on tangent track and curve negotiation performance on whether sharp, medium, or large curved track. For example, passing through a curve with a radius of 200[Formula: see text]m, the IRW friction work has the biggest drop by 62.07% and the wheelset attack angle is second with a reduction rate of 55.02%. Adopting of larger steering stiffness, smaller steering clearance, and lever ratio greater than the ideal value can guarantee the higher steering ability of FSD. Besides, lower longitudinal stiffness of the trailer primary suspension is recommended because it can also enhance the steering ability of the FSD.

Comparison of train noise and vibration measurements with U.S. Department of Transportation model predictions

Wayside noise and ground-borne vibration measurements of freight and light rail train operations were carried out in Denver, CO in support of the Burnham Yard Transportation Planning Study being pursued by the Colorado Department of Transportation (CDOT). This study was intended to evaluate various track layout alternatives for the Consolidated Main Line (CML) freight railroad alignment and enhancement of Regional Transportation District (RTD) light rail operations while maintaining options for Front Range Passenger Rail (FRPR) within Burnham Yard and the surrounding areas. The objective of the measurements was to compare measured train noise and vibration levels with predictions using models sanctioned by the U.S. Department of Transportation (USDOT) in order to validate the use of these models to assess the noise and vibration impacts of the project alternatives. The models included the Federal Railroad Administration (FRA) Chicago Rail Efficiency And Transportation Efficiency (CREATE) freight noise model, the FRA Horn Noise Model, and the models included in the Federal Transit Administration (FTA) Transit Noise and Vibration Impact Assessment Manual. Based on a comparison of measured and modeled results, it was concluded that the USDOT models could be used to assess noise and vibration from train operations in the Burnham Yard Study Area.

An alternative assessment for transit-oriented developments (TODs) with land use/land cover (LULC).

Cities experience rapid growth, and various drivers shape this growth. Notably, developing countries experience challenges on land use and transportation conflict. The idea of transit-oriented developments (TODs) is a solution for this concern of urbanization while there is no consensus on defining and identifying them. This study concentrated on the dynamics of land use/land cover (LULC) effects on transit-oriented developments (TODs) by utilizing light rail stations from a metropolitan area in Turkey, as this is the first attempt in this geography. Spatial data covers of high-resolution Sentinel 2A remotely sensed data and Google Earth images acquired in 2021. The study performed the analyses within a 500-m light rail train station buffer. The results reveal that TODs include more urbanized, open space, street connection, commercials, and dense population as expected from the TOD concept. Local officials, practitioners, and developers should be involved with the TOD implementation and policy phases to establish tangible developments in urbanization.

New light rail vehicle and drivetrain concepts for catenary free operation of branch lines

This paper proposes a new light rail train concept suitable for battery-only, hydrogen and diesel operation of branch lines. A simulative methodology is presented, analyzing these drivetrains within the new train concept. The simulation features a detailed train model, including a propulsion and an auxiliary model. System effects such as the use of waste heat for heating the train are considered, analyzing the drivetrain options in detail. 31 railway lines in Germany and France are analyzed taking various environmental conditions into account. The drivetrains are compared assuming climate neutral operation based on hydrogen and diesel made from electricity. The battery train is the most energy-efficient solution, followed by hydrogen which can be an option on longer tracks. The diesel train needs twice as much energy as the hydrogen train, which makes it not economically suitable.

Commutation Behavior and Stray Inductance Analysis of a FC-3L-BDC Phase-Leg PEBB

The bidirectional dc-dc converter is a critical component for extending the use of renewable energy and improving the efficiency of high-power electronic systems. This paper presents the analysis of the stray inductance of a commutation loop and the commutation behavior of IGBT devices in a flying capacitor three-level bidirectional DC-DC converter (FC-3L-BDC) phase-leg power electronic building block (PEBB). An FC-3L-BDC phase-leg PEBB was designed as an example, which can be used to build 400 kW to MW-grade light rail train chargers, battery energy storage interface converters, or metro regenerative braking energy recovery converters with a single PEBB or several PEBBs interleaved parallel. In order to optimize the stray inductance of commutation paths and realize snubberless operation, a five-layer laminated bus bar was carefully designed, and the stray inductance of the bus bar was extracted by three-dimensional finite element analysis simulation. To obtain higher accuracy, the stray inductances of IGBT devices and capacitors were extracted from the test instead of their datasheets. Then, the accuracy of the commutation loop stray inductance analysis method was verified by practical experiments. The impact of the stray inductance of the commutation loop on the commutation behavior of IGBT devices was analyzed, and the switching characteristics of IGBT devices were measured under maximum DC-link voltage and entire current rating range at the temperatures of −40 °C, 25 °C, and 150 °C, respectively, finding that neither the excessive turn-off overvoltage of IGBTs nor the snappy reverse recovery of FWDs was observed.

Transit justice: community perceptions and anticipations of a new light rail transit line in Prince George’s County, Maryland, United States

ABSTRACT Transit-oriented developments are increasingly important as they address many modern urban environment problems such as urban sprawl, pollution, and rising rates of non-communicable diseases. However, their implementation is difficult as cities are complex systems. Urban health improvements is a labyrinthian process as enhancements in one area often leads to several unintended side effects, such as transit-induced gentrification or injustice. The Purple Line Impact on Neighborhood, Health and Transit (PLIGHT) study examines the community impact of a forthcoming light rail train line in Prince George’s County, Maryland, a predominantly Black and Hispanic community. Results show that despite mindful planning the Purple light rail train is subject to ‘Transit Orientated Development’ idealism, which can propagate transit injustices. This qualitative study highlights the disconnect between this idealism and practice. It explicitly identifies the most vulnerable of transit users and highlights how neoliberal urbanism contributes to health inequities in Transit Orientated Development practice.

Metro Futures 2020: Enabling Participation at Varying Depths and Scales via Digital Technology

Large scale urban planning consultations can elicit public contributions with limited reflectivity and scope in comparison with participatory projects in HCI. We therefore investigated how digital technology can be configured to enable participation at greater depth and at scale in Metro Futures 2020 – an online public consultation on light rail trains. Drawing on participatory methods used in HCI, we devised experience-centered and creative activities at different depths and scales – from “shallow and wide” social media polls to “deep and narrow” online workshops – and a website with three ways of exploring a digital train mock-up. Participation on the website was both at scale and to notable depth according to our analyses of data entry behavior and website comments. Our findings show that the value of online public consultations can be increased through providing experiential context for design proposals, supporting exploration of design details via immersion, and providing interconnected activities of varying depths and scales.

A Novel Train Roof-Top Wind Energy Conversion System

Cities all around the globe are ramping up efforts to transform their infrastructure in order to achieve a carbon-neutral and sustainable future, resulting in fast electrification of transportation networks. The need for power in this industry is rising, notably in light rail transit. Application of train rooftops wind energy conversion has the potential to power light rail transits with renewable energy. This research paper presents a way to generate electrical energy by utilizing strong wind pressure from light rail trains that channels the induced wind towards the turbine. The current invention's main aim is to establish a method and system for producing energy utilizing winds that can be conveniently available in the operation of trains. Here the wind energy is independent of the variations in the direction and speeds in which seasonal winds move, which do not have the appropriate wind force or force at all times or places for operating the wind turbines. Vertical axis wind turbines are selected due to their advantage for the application under consideration. SOLIDWORKS and MATLAB simulation software were used for the design of the Train Roof-Tops Wind Energy Conversion System (TRT-WECS). The former was used to perform computational fluid dynamics (CFD) on the both normal train as well as the train having a turbine installed on the top, and a comparison has been made in terms of various parameters that affect the performance of the newly designed TRT-WECS. A mathematical model comprising mechanical and electric components has been developed by using MATLAB. Finally, the study found out that this special TRT-WECS design installed in each train provides an annual energy output of 4.9 MWh.

Station facilities and noise assessment: A multilevel analysis on light rail train stations

Noise is one of the most frequent consequences of traffic. Public transportation systems, such as the Dallas Area Rapid Transit (DART) authority provides various modes of transportation. Even though the availability of commuting service for the public is a boon to communities, mass transit systems are potential sources of excessive sound levels in daily urban life. This article examines the nexus between the transit station facilities of light rail train (LRT) stations and noise implications at both station and neighborhood scales by studying selected LRT stations. A multilevel linear analysis was conducted to understand the degree of train station amenities and neighborhood characteristics that affect sound levels. Using a type II sound pressure level (SPL)meter, sound measurements were obtained during the weekdays and weekends over several weeks. Upon examining the station amenities, and built environment and sociodemographic characteristics of the neighborhood, findings of this comprehensive research reveal significant implications for sound levels. Stations with ticket vending machines and informative message boards include a higher degree of significance on SPLs, while shelters, crew rooms, bike lockers, restrooms, and windshields are significantly and negatively associated with the noise levels. Additionally, neighborhoods with dense roads, higher speed limits, more neighborhood facilities, and a higher number of transit routes have an increased likelihood of noise levels. Recommendations include creating transformative policies for implementation, and approaches addressing noise for transit authorities, transportation engineers, and planners are presented. Planning and engineering aspects of comfort, aesthetics, safety, and public health, as train stations are daily use spaces for commuters and surrounding communities, should also be considered.

Effect of the Material Parameter and Shape of Brake Pads on Friction-Induced Disc Brake Squeal of a Railway Vehicle

To study the mechanism of brake squeal of light-rail trains, a field test and a simulation analysis of disc brake squeal were carried out. In the field test measurement, the noise and vibration characteristics of brake components under normal braking and abnormal braking were analyzed. The test results show that the peaks of the frequency spectrum of the squeal noise and brake pad vibration correspond. The occurrence of brake squeal is closely related to the abnormal vibration of the pads. According to the theory of friction self-excited vibration, a finite-element model of the disc brake system of the light-rail trains was established. Effects of the material parameters and shape of the brake pad on the tendency for brake squeal were studied using complex eigenvalue analysis. The simulation results show that increasing the Young's modulus of the brake pads can effectively suppress brake squeal, but a larger or smaller Poisson's ratio of the brake pads was not conducive to suppressing brake squeal. Changing the shape of the brake pad will lead to differences in the number, frequency, and instability of unstable modes. It is observed that the shape of the brake pad has a significant effect on suppressing brake squeal. The grooved pad has a better effect in suppressing brake squeal.

Simulation Research on the Braking Characteristics between Tires of the 3-Module Virtual Track Train

The virtual rail train is a new type of urban rail transportation, which integrates some of the characteristics of buses, trams and light rail trains. In order to study its braking stability, the paper appeared from the perspective of vehicle dynamics, studying the braking force allocation strategy of the train under different working conditions. It is proposed to calculate the articulation force of the train from the motion parameters of the train, and analyze the dynamic change of the tire vertical load. The lateral force is prioritized to ensure that the train turns stably and avoiding tire slip. After that, the remaining braking force is used to maximize the utilization of braking force. The results show that this method of braking force allocation between tires can ensure that the tires are not locked, while ensuring the braking strength.

Capacity Assessment of Railway Stations: A Case of Addis Ababa Light Rail's Menilik Square Station.

Addis Ababa, capital city of Ethiopia, is experiencing a population boom and rapid urbanization. Passenger demand on the Addis Ababa Light Rail Train (AALRT) in recent years has not been matched by the equivalent available capacity, thus maintaining system performance is an increasing challenge. The objective of this paper was to assess the performance of Menilik Square LRT Station in terms of the number of passengers boarding the train mainly during peak hours. Capacity utilization of the rolling stock at the station in terms of passengers carried, number of trains that arrive at the station during peak hours and passenger volumes per train during peak hours has been analyzed. Data collected from the AALRT authority office for the month of November 2019 has been used to conduct the analysis. It has been discovered that there is overcapacity utilization during peak hours with 400 excess passengers, for a design capacity of 8000 passengers. Finally, it is recommended to minimize the dwell time at the station and minimize the headway between the trains to increase the throughput at the station thus minimizing overloads per train.

Constraining Urban CO2 Emissions Using Mobile Observations from a Light Rail Public Transit Platform.

Urban environments are characterized by pronounced spatiotemporal heterogeneity, which can present sampling challenges when utilizing conventional greenhouse gas (GHG) measurement systems. In Salt Lake City, Utah, a GHG instrument was deployed on a light rail train car that continuously traverses the Salt Lake Valley (SLV) through a range of urban typologies. CO2 measurements from a light rail train car were used within a Bayesian inverse modeling framework to constrain urban emissions across the SLV during the fall of 2015. The primary objectives of this study were to (1) evaluate whether ground-based mobile measurements could be used to constrain urban emissions using an inverse modeling framework and (2) quantify the information that mobile observations provided relative to conventional GHG monitoring networks. Preliminary results suggest that ingesting mobile measurements into an inverse modeling framework generated a posterior emission estimate that more closely aligned with observations, reduced posterior emission uncertainties, and extends the geographical extent of emission adjustments.

Governance and administrative process of the Light Rail Train project in Palembang, Indonesia

PurposeThe paper investigates the governance and administrative process in the Palembang Light Rail Train (LRT) project in Indonesia and gives suggestions on the strategic development of the LRT project for creating a desakota technopole in Palembang.Design/methodology/approachThis paper adopts both STEEP (Social, Technological, Environmental, Economic, Political) analysis and desakota technopole theoretical framework. The STEEP analysis is used to explain the Palembang LRT project which is to meet one of the city’s high-tech urban transportation goals. The desakota technopole framework is used as a strategic urban planning guideline for the further development of Palembang.FindingsThis paper has three findings. First, based on STEEP analysis, Palembang needs smart urban transportation, such as LRT, to solve the present and future traffic problems. Second, the governance and administrative process in the LRT project is mandated to national companies as part of a national government infrastructure policy financed over multiple years through the national budget. Third, it is critical for national, provincial, and local governments to adopt a desakota technopole framework strategy to meet long-term targets.Originality/valueThis paper highlights Indonesia experience towards making a desakota technopole, using the Palembang LRT project policy as the key driver under investigation.

The TRAX Light-Rail Train Air Quality Observation Project

Observing air quality from sensors onboard light rail cars in Salt Lake County, Utah began as a pilot study in 2014 and has now evolved into a five-year, state-funded program. This metropolitan region suffers from both elevated ozone levels during summer and high PM2.5 events during winter. Pollution episodes result predominantly from local anthropogenic emissions but are also impacted by regional transport of dust, chemical precursors to ozone, and wildfire smoke, as well as being exacerbated by the topographical features surrounding the city. Two electric light-rail train cars from the Utah Transit Authority light-rail Transit Express (“TRAX”) system were outfitted with PM2.5 and ozone sensors to measure air quality at high spatial and temporal resolutions in this region. Pollutant concentration data underwent quality control procedures to determine whether the train motion affected the readings and how the sensors compared against regulatory sensors. Quality assurance results from data obtained over the past year show that TRAX Observation Project sensors are reliable, which corroborates earlier preliminary validation work. Three case studies from summer 2019 are presented to illustrate the strength of the finely-resolved air quality observations: (1) an elevated ozone event, (2) elevated particulate pollution resulting from 4th of July fireworks, and (3) elevated particle pollution during a winter time inversion event. The mobile observations were able to capture spatial gradients, as well as pollutant hotspots, during both of these episodes. Sensors have been recently added to a third light rail train car, which travels on a north–south oriented rail line, where air quality was unable to be monitored previously. The TRAX Observation Project is currently being used to provide reliable pollutant data for health studies and inform urban planning efforts. Links to real-time data displays and updated information on the quality-controlled data from this study are available on the webpage for the Department of Atmospheric Sciences at the University of Utah.

Strength Analysis of Metro Kapsul Knuckle Plate and Tie Rod using Finite Element Method

Metro Kapsul is a public transportation system developed to solve traffic problems and save travel time in Bandung. It is categorized as a light rail train with a capacity of 70 passengers per capsule. Before it operates, analysis is needed to ensure the vehicle’s safety. Two crucial parts to be analysed are the knuckle plate and the tie rod of the train. The knuckle plate and the tie rod must meet the requirements of the standards based on PM 175 2015. Forces on each component are calculated using equations from free body diagrams. Static and fatigue analysis are then conducted using ANSYS with Finite Element Method based on load cases in UIC Code 615-4 standard. The maximum stresses that occurred are 195.64 MPa for the knuckle plate and 118.54 MPa for the tie rod. In terms of fatigue, based on the modified Goodman failure criteria, the knuckle plate and tie rod are proven to be safe.

Modal parameters identification of light rail bridges

One of important aspect in Structural Health Monitoring System (SHMS) is the initial condition of the structure. This paper studies the initial condition of light rail train (LRT) bridges before officially operated. There are four bridges to be evaluated, consists of three simple supported bridges and one continuous bridge. Data measurement was using tri-axial accelerometer EZDYN with a train-set as the dynamic loading source. The modal parameters are obtained by means of operating modal analysis (OMA) in time domain. Three methods are simulated, that are ARMA, ITD and SSI. The data processing applied shows that all three methods give satisfactory results that confirm each other, for both natural frequencies and vibration modes.

Modelling growth principles of metropolitan public transport networks

The development of metropolitan public transport networks often involves choosing between investing in extending radial lines or constructing ring connections. While the former enlarges network coverage the latter enhances network connectivity and reduces the need to perform detours. Moreover, investments might be better directed at increasing the capacity of already existing infrastructure. In this study we address the following question: how do transport networks in metropolitan areas evolve over time and how can we effectively model this growth as function of demand and cost function? The goal of this study is to determine the fundamental relations between population distribution, modal costs on the prevailing network structure and its evolution. The approach taken in this study offers a theoretical contribution to the field of transport network growth by combining principles from several research streams: transport geography, economics of network growth and network science. We propose an iterative investment model network analysis framework. The results of the network growth experiments manifest an overall trend in network growth with an early phase of expansion of the network, followed by a period of intensification manifested in capacity increments and finally adding some links that contribute to its densification. Furthermore, our findings suggest that bus networks include more ring-radial connections than Light Rail Train and Metro networks which are more concentrated on radial connections.

Modeling, Analysis and Implementation of an Urban Electric Light-Rail Train Hydrogen Powered

A novel hydrogen power configuration of a Light Hybrid Electric (LHE) rail train able to operate along sub-urban non-electrified rail lines is proposed and analysed in the paper. The electric motors of the emission-free LHE rail train are fed by a hybrid power unit consisting of hydrogen fuel cell stacks and a set of high-speed kinetic energy storage systems. A control strategy of the power-train components has been developed to manage power flows in order to reduce the fuel consumption. This advanced and environment friendly hybrid propulsion system offers the opportunity to increase the power-train efficiency so that the fuel consumption is minimised. Simulator software of the proposed HLE rail train has been implemented in order to design the power-train components and compute train performance. A rail transport service is considered and a round trip journey of the LHE rail train is simulated over an existing re-designed not electrified single track line in the sub-urban area of L’Aquila city (Italy). Furthermore, the specific fuel consumption comparative analysis between the hydrogen rail train and a diesel one running over the selected path in the same operating conditions has been performed and the results are discussed in terms of CO2 emissions too. The results show that the proposed LHE rail train is technically suitable and advantage to operate in urban environment.

State-of-the-art review of bridges under rail transit loading

A state-of-the-art review on the global behaviour of bridges under rail transit loading is presented. Of interest is a synthesis of recent technical findings that can bridge the gap between research and practice. The literature review revealed that structural responses have been evaluated and finite-element and analytical models developed. Identification techniques appear to be useful to extract the dynamic characteristics of rail bridges. Impact increases static load in conjunction with dynamic amplification; however, it tends to converge with train speed. The impact force of a wheel–track system is affected by train weight and speed, rail irregularities and rail type. A number of parameters are associated with rail break. The occurrence of rail breaks increases dynamic load allowance and could cause train derailment. Longitudinal forces induced by thermal loading are another important factor in understanding rail–structure interaction. Contrary to highway bridges, limited effort has been made for railway bridges in terms of reliability investigations and the calibration of load and resistance factors. Scarce information is available on bridge responses associated with light rail trains. Several transit agencies have developed design guidelines using their own live load models. A standard live load model for light rail transit is required to achieve uniform design outcomes.