Rail Car Research Articles

Long Short-Term Memory Autoencoder for Anomaly Detection in Rails Using Laser Doppler Vibrometer Measurements

Abstract This study presents an application of Long Short-Term Memory Autoencoder (LSTM AE) for the detection of broken rails based on laser Doppler Vibrometer (LDV) measurements. This work is part of an ongoing project aimed at developing a non-contact damage detection system using LDV measurements. The damage detection system consists of two laser Doppler vibrometers (LDV) mounted on a moving rail car to measure vibrations induced on the rail head. Field tests were carried out at the Transportation Technology Center (TTC) in Pueblo, CO, to collect the vibrational data. This study focused on the detection of broken rails. To simulate the reflected and transmitted waves induced by the broken rail, a welded joint was used. The data was collected from moving LDV measurements, in which the train was operating at three different speeds: 16km/h (10mph), 32km/h (20mph), and 48km/h (30mph). After obtaining the data, filtering and signal processing were applied to obtain the signal features in time and frequency domains. Next, correlation analysis and principal component analysis were carried out for feature selection and dimension reduction to determine the input used to train and test the LSTM AE model. In this study, the LSTM AE models were trained based on different data sets for anomaly detection. Consequently, an automatic anomaly detection approach for anomaly detection based on the LSTM AE model was evaluated. The results show that the LSTM AE model can efficiently detect the anomaly based on the selected features at three different speeds.

An impulsive noise filter for rail vibration measurements using a laser Doppler vibrometer on a moving platform

This paper proposes a new impulsive noise (i.e., IN) filter for non-contact rail vibration measurements performed by a laser Doppler vibrometer (i.e., LDV) placed on a moving rail car. The development of the filter is motivated by the fact that such measurements can be contaminated by IN, which is caused by a high level of speckle noise due to the movement of the LDV. Consequently, some portions of the LDV signals can be distorted, leading to missing measurements from some rail segments. The proposed filter consists of two main steps: (i) detecting the signal segments containing the IN (i.e., detection step), and (ii) replacing the detected segments to estimate their IN-free values (i.e., estimation step). The performance of the filter was evaluated on a synthetic signal, which was created by combining a rail vibration signal in the vertical direction (i.e., vibration component) with a speckle noise signal of an LDV placed on a moving platform (i.e., noise component). The reason to use a synthetic signal was to know the vibration and noise components separately. This allowed for the examination of IN’s behavior, which showed that IN manifests itself as artificial peaks as well as high-frequency noise in the proximity of artificial peaks (i.e., artificial fluctuations). Accordingly, the proposed filter was designed to detect and replace both artificial peaks and fluctuations. Qualitative and quantitative evaluations of the filtered synthetic signal showed that the proposed filter exhibited good performance in mitigating the IN.

The Influence of Seasonal Effects on Railway Vertical Track Modulus

Adequate vertical track support is essential for safe and efficient railway operations. Insufficient support leads to distorted track geometry, increased dynamic loads, component stress, poor ride quality, rolling stock damage, and derailment risks. Current inspection practices focus on assessing the condition of the track components and geometry, rather than the root causes of degradation. To improve this condition, this study presents the use of a methodology that utilizes an autonomous vertical track deflection measurement system mounted on a loaded rail car (36 tonnes/axle) to support track maintenance decisions in a heavy haul railroad located in southeast Brazil. The system continuously measured substructure stiffness along the railway line. Over one year, data were collected from over 8000 km of track. The study highlighted seasonal effects on track degradation over time, identifying areas with significant deflections and high deflection rates, which contribute to issues such as differential settlement and reduced lifespan of track components. Additionally, the study revealed seasonal effects, with deflections peaking during wet weather and decreasing during dry cycles. A method to classify weak track areas was developed, facilitating monitoring and enabling more effective maintenance planning, contributing to the reduction of overall track maintenance costs and enhancing safety and operational efficiency.

DECISION-MAKING SUPPORT TECHNOLOGIES IN THE FORMATION OF QUALITY MANAGEMENT SYSTEMS AT VEHICLE REPAIR ENTERPRISES

In recent years, the strategy of creating a safely functioning and efficient transport complex of Ukraine integrated into the world transport network has been fixed. Therefore, the creation of a progressive system of product quality management in the conditions of car repair enterprises is considered an urgent scientific and technical task. The quality management system is a management subsystem of an industrial enterprise. Modern production systems are based on TQM principles and widely use ISO 9001 certification. At the same time, certification is based on independent third-party audits (a conformity assessment organization). The wide spread of the standard is based on the fact that it contains generalized requirements (principles) for the organization of product quality control, which can be used at enterprises that differ significantly both in terms of specialization and the scale of production (depots or car repair plants). But this is the «bottleneck» of the standard – the lack of consideration of specialized production conditions makes it impossible to compensate for critical factors affecting the final quality of products. Currently, the accepted approaches to quality assessment do not fully take into account the factors that affect the final quality of products. In order to put all market participants - railway operators, manufacturers, rolling stock repairers and suppliers in mutually beneficial conditions, a single International Railway Industry Standard ISO / TS 22163 International Railway Industry Standart (IRIS) was developed.For the effective use of tools for ensuring the quality of rail car repair, it is considered necessary to use modern management decision support systems. They will allow real-time monitoring of production processes. It is possible to use the method of fuzzy sets to improve the quality management systems of wagon repairs based on the development of separate control algorithms with decision tables. In order to meet the requirements of international quality standards, it is necessary to significantly modernize management approaches based on the creation of progressive decision support systems.

Supply chain risk in grain trading: Inventories as real options for shipping grain

AbstractIntegrating trading and logistics is an important challenge in commodity trading. Trading and logistics are strategic decisions and are integral to most commodities including grain shipping by rail, in addition to other modes (barges, ocean shipping). There are substantial risks, such as the ordering and placement of rail cars. The other risk is having sufficient grain stocks to load rail cars. Alternatives for managing these risks include holding grain inventories and the strategic use of shipping options. The purpose of this study is to develop a model for determining an optimal grain inventory strategy for shippers. The real option methodology is used to value uncertainty in rail car velocity and determine optimal purchases and inventories. The results show the importance of integrating trading and logistics decisions and illustrate that inventories can be interpreted and valued as real options that are affected by uncertainties. Taken together, the real options indicate how much extra inventory shippers should maintain to mitigate risks and maximize profits.

Jam in the Tunnel: On Urban Freight Tunnels, Their Operational Scheduling, and Unused Transport Capacity

Underground passageways for the transport of goods and people have fascinated mankind throughout the centuries. Recent initiatives in different parts of the world aim at rekindling the freight tunnel concept for urban logistics. According to this concept, freight is lifted into a tunnel, moved via electrically powered vehicles, rail cars, or maglev shuttles toward inner-city microhubs, and finally delivered with environmentally friendly vehicles to urban recipients. The main justification for this concept to outweigh the huge tunnel boring cost is a substantial reduction of road-based urban freight traffic. To warn about unfulfilled expectations, however, we show that the combination of time-critical goods, small inner-city hubs with restricted storage capacity, and the wrong booking procedure can hinder a loading of tunnel vehicles to capacity. To do so, we consider a polynomially solvable scheduling problem where due date-restricted shipments are to be assigned to tunnel vehicles and delivered to a given set of microhubs with limited storage capacity. Scarce hub capacities, tight due dates, and the wrong booking policy may not only lead to unused tunnel capacity but also to shipments that cannot be feasibly transported through the tunnel. If they are handed over to trucks as a fallback option, we show that a Braess-like paradox can occur: The time-critical, small-lot transports of the leftover shipments can produce even more surface traffic than trucking all shipments right from the start without the tunnel. Supplemental Material: The online appendices are available at https://doi.org/10.1287/serv.2023.0005 .

Modernization of Railway Wagons for Customer Satisfaction and Safety

This article focuses on the assessment of the efficiency of the modernization of railway wagons intended for passenger transport. The modernization of railway wagons is an important step towards ensuring the safer and more efficient operation of railways. However, this modernization is not without risks and, in addition to its many positive effects, it can also bring new challenges in the form of breakdowns and technical problems. Failures in passenger rail vehicles are a challenge facing manufacturers and transport operators, and identifying the relationships between these failures can help to improve the design, manufacture, and maintenance of these vehicles. Passenger rail vehicle failures can vary in nature, whether mechanical, electrical, or inside the vehicle. This paper attempts to provide a comprehensive view of the effectiveness of passenger rail car retrofitting based on the data collected and statistical analyses. The article further focuses on the description of selected rail passenger wagons, describes the analyses of the statistical data using the correlation between the selected rail wagon failures and their significance, in addition to whether the impact of modernization reduces the number of rail wagon failures. The results of this statistical analysis can be used to better understand the impact of modernization on different aspects of passenger transport and will help in making future investment and policy decisions in this area. © 2017 Elsevier Inc. All rights reserved.

The Strength of Rail Vehicles Transported by a Ferry Considering the Influence of Sea Waves on Its Hull.

The article presents the results of a determination of the load attributed to rail vehicles transported by a ferry, considering the influence of sea waves on its hull. A mathematic model describing the displacements of a train ferry, which transported rail vehicles on its decks during rolling oscillations, was created. Calculated accelerations were used to identify the load of components from a dynamics point of view and they were subsequently applied as an input to the analysis of the strength of the open wagon main-bearing structure in a standard scheme of interaction with a train ferry deck. The calculated maximal equivalent stresses in the structure of the fastening units exceeded the valid permissible values. To confirm the theoretical results, experimental studies focused on the strength analysis of the open wagon placed on the railway ferry deck, which was performed in real operational conditions. Electrical voltage sensors were used to determine stress distribution in the areas where the body was attached to the deck. In this case, sensors of the strain gauges, i.e., tensiometers, were used. The base of 25 mm is a dimensional parameter and the resistance, 124 Ohms, is the tensiometer parameter. Verification has been performed and, based on the obtained experimental results, it has been established that the hypothesis' adequacy is not rejected. The authors developed some measures for adaption of the lashing devices for rail cars on train ferries, which can ensure their safe transportation by sea. The strength calculation demonstrated that, in the new scheme of securing the transported railway vehicles on the railway train ferry, the stresses in its structure do not exceed the permissible values. The article also includes information about the results of the strength calculation of a container placed on a roll trailer transported by a train ferry. This research will contribute to the development of measures regarding the safety of railway vehicle transportation by sea ferry and better efficiency of train ferry transportation.

Strengthening Riveted Joints of the Grain Rail Car Backstop

Strengthening Riveted Joints of the Grain Rail Car Backstop

Strength Analysis of an Open Car Body with Honeycomb Elements during Ro-Ro Transportation

This article presents the determination of the bearing structure loads of an open car during ro-ro transportation. A special solution for an open car is the application of elastic, viscous honeycomb panels in the frame. This engineering solution can decrease the load of the bearing structure of an open car during interactions with multiple-use lashing devices. This article presents the mathematic modelling of the dynamic load of an open car during ro-ro transportation. This calculation is based on the most popular load diagrams for the bearing structure of an open car applied for sea transportation, namely the rolling motion and the turning motion of a train ferry approaching a dock. It was found that the application of honeycomb panels can decrease the dynamic load of a rail car in comparison to a standard structure by about 25%. The results of the strength calculation of the bearing structure of an open car demonstrated that the maximum equivalent stresses do not exceed the allowable values and are 30% lower than the stresses that emerging in the standard structure. The conducted research can be used by engineers who are concerned about safe and environmentally friendly transportation via train ferries and more efficient ro-ro transportation.

Effect of Flow Rate on Smoke Control System for Railway Tunnel Fire

Tunnel is a semi-closed structure with a high risk of fire becuse of difficulty of smoke exhaust and restricted evacuation route in fire. No specific guidelines on smoke control systems have been developed for railway tunnels. Therefore, in the railway tunnel design, an average airflow velocity of 2.5 m/s inside a tunnel for the entry and exit of workers has been used as a reference. In this study, a fire simulation conducted to examine whether the average flow velocity can sufficiently apply on smoke control system in railway tunnel design. An 870-m-long railway tunnel with a single track and double track was modeled, and fire scenarios for light rail cars were simulated. It was found that the reference flow velocity showed sufficient smoke control performance, even at a maximum fire source of 60 MW. However, evacuees might be exposed to smoke due to the backlayer formed immediately. Furthermore, the smoke control performance for the reference velocity does not reflect the influence of the tunnel length. It is necessary to conduct a study on standard for appropriate smoke control performance to reduce fire risk in a railway tunnel fire.

A rail defect detection system based on laser Doppler vibrometer measurements

This paper aims at introducing a non-contact rail damage detection system based on laser Doppler vibrometer (LDV) measurements. Specifically, the system consists of two LDVs mounted on a rail car, to record the waves induced on the rail head by random rail-wheel interaction forces.The developed damage detection framework associated with the system is based on a multivariate analysis that combines damage features which are based on the relative change in amplitude of the LDV signals that are caused by both reflected and transmitted waves. In this study, the damage detection system is introduced and validated through field tests which were carried out at the Transportation Technology Center (TTC) in Pueblo, CO. In these tests, a rail car installed with the damage detection system traveled over a track that consisted of a discontinuity in the rail (i.e., welded joint) at different speeds up to 48 km/h (30mph). Results show that the proposed system can identify the rail segment in which the propagating waves on the rail head are affected by the presence of the welded joint.

Effect of primary suspension and friction wedge maintenance parameters on safety and wear of heavy-haul rail vehicles

Wheel wear is of major interest in railways due to the high cost of wheel reshaping, rail wear, and safety issues in operation. Recent researches employ onboard sensors to evaluate the dynamic behavior of the wagon and determine railway running conditions. However, sensors and computing units are expensive and some maintenance scenarios are impossible to be deliberately generated. In this work, several maintenance parameters for primary suspension, friction wedge, and flange backspacing are evaluated within operational ranges in a Box-Behnken design of experiment (DoE), set in a quadratic surface model. Such a modeling approach uses few experimental points and a significantly small computational cost when compared to a full factorial method, which uses multibody dynamic models on a simulating platform, like Simpack, to determine which parameters are more influential in safety against derailment (Y/Q) and wheel and flange wear (Tγ). The present work evaluates such parameters for heavy-haul gondola rail cars, with meter and broad gauge, running on tangent track and curves, with and without FRA irregularities. The analysis makes it possible to identify non-uniformities in wheel wear and to set different inputs for condition-based maintenance for freight rail wagons. Results show that the primary suspension longitudinal clearance and stiffness affect Y/Q and wear by over 100%, increasing the operational risk and maintenance cost because of wheel wear.

Thermal comfort of novel low-momentum ventilation concepts for passengers in long-distance trains

Thermal comfort is essential to increase the modal share of rail transport by attracting more passengers. In this study, three novel low-momentum ventilation concepts were analyzed regarding the thermal comfort of railway passengers and compared to a conventional ventilation setting. Using an experimental approach, objective measurements of climate parameters and subjective assessments from 146 test subjects in a generic train compartment were analyzed. Results revealed significant differences in perceived thermal comfort amongst the four ventilation settings. Subjects reported comparatively higher thermal comfort in hatrack integrated low-momentum ventilation and hybrid ventilation (HV) than in cabin displacement ventilation (CDV) and microjet ventilation (MJV). Vertical temperature stratification was strongest in CDV, leading to losses in the comfort of the lower body parts. In MJV, some temporary and local exceedances of air velocities were observed, which contributed to lower comfort evaluations at heads and shoulders. For all ventilation settings, warmer air temperatures were preferred. Our findings demonstrated that subjective comfort assessments reasonably complement earlier results derived from thermal manikin studies. Therefore, low-momentum ventilation, especially in terms of HV, has the significant potential to improve thermal conditions for long-distance journeys in passenger rail cars.

Recycled Glass Polypropylene Composites from Transportation Manufacturing Waste

In recent years there has been growing interest in developing recycling technologies for composites manufacturing scrap, process waste and end-of-life parts. The focus of this work was to establish processing routes and mechanical property bounds for glass-polypropylene (PP-GF) scrap from the production of parts for truck trailers, automobiles, and rail cars. This study considered PP-GF scrap and demonstrated extrusion-compression molding (ECM) as a viable route for the closed-loop manufacture of composite parts. The results were promising in terms of the strength and modulus retention of the PP-GF recyclate. The tensile strength and modulus was the highest for 50% and 66% recycled content, compared with 100% and 83% recycle content. The flexural strength and modulus of the 100% and 83% recycled compositions was higher than the 66% and 50% recycled content, respectively. The impact energy absorption of the PP-GF recyclate at at all fiber loadings was superior in absorbing energy compared with the incumbent (benchmark) plywood. This work is useful to designers seeking to incorporate recycled materials in their products.

Modernization of the Hydraulic Drive Opening and Closing the Chute Doors for Rail Cars in Coke-Quenching Systems

Modernization of the Hydraulic Drive Opening and Closing the Chute Doors for Rail Cars in Coke-Quenching Systems

Analisis Kerusakan Pada Permukaan Roda Kereta Rel Listrik

The wheels of electric rail cars are an essential component of rail transportation when they are in use. At the time of inspection, the technician discovered damage to the wheel's surface. This is due to the hardening of the brake block, which damages the wheel's surface. This research was conducted with the purpose of analyzing the causes of damage to the tread surface of the wheels and identifying a suitable replacement for the original brake block, which is no longer manufactured and has been replaced by imitation block brakes. so that further action can be taken to prevent similar occurrences in the future. Using the Vickers hardness test indentation method, the purpose of this study is to examine various heat treatments for determining a material's hardness level. The test results indicate that the VHN value increases with increasing heating temperature. The original specimen produced 99.5 VHN in the first test without heat treatment, while the X block brake produced 26.9 VHN and the Y brake produced 136.0 VHN. The second test with 200°C heat treatment on the original specimen yielded 96.8 VHN, 73.1 VHN from the X block, and 152.9 VHN from the Y block. In addition, the third test with 400°C heat treatment on the original specimen produced 92.4 VHN, 47.8 VHN for the X block brake, and 268.3 VHN for the Y block brake. The Vickers Hardness Test (VHN) hardness value is affected by heat treatment; the higher the heating value, the higher the hardness value of the remolok specimen.

Parameter Optimization of Gas Metal Arc Welding Process for Welding Dissimilar Steels

Welding is a method of joining similar and dissimilar metals through the use of coalescence. GMAW is a semi-mechanized, fully-mechanized, or automatic process that is widely used in fabrication. GMAW is expected to evolve further to allow for better arc control, bead contour control, deposition control, and higher productivity. The goal of this study is to enhance welding process variables for dissimilar steel metal joints made of duplex stainless steel (DSS) to ASTM/UNS S32205 and erosional steel CORTEN-A to ASTM A242. Such a dissimilar metal joint finds use in the transportation sector, particularly in the construction of rail cars. The square butt joint between two 2 mm-thick sheets was investigated using the gas metal arc welding (GMAW) process with CO₂ as the shielding gas and flux-cored wire of grade 309L as the filler material. The L₉ Taguchi array was used to optimize the tensile strength of the resulting weld joint, which was the desired quality characteristic. GMAW process parameters such as voltage, wire feed rate, and welding speed are optimized at three levels. Using ANOVA, the effects of each factor have been studied. It was found that the ideal set of parameters exists and that the voltage is the most crucial factor. A confirmation test was performed to validate the results, and it was accompanied by a figure and tables.

Gas Metal Arc Welding Process Variables Enhancement for Welding Significantly different Steels

The goal of this study is to enhance welding process variables for dissimilar steel metal joints made of duplex stainless steel (DSS) to ASTM/UNS S32205 and erosional steel CORTEN-A to ASTM A242. Such a dissimilar metal joint finds use in the transportation sector, particularly in the construction of rail cars. The square butt joint between two 2mm thick sheets was investigated using the gas metal arc welding (GMAW) process with CO2 as the shielding gas and flux cored wire of grade 309L as the filler material. The L9 Taguchi array was used to optimize the tensile strength of the resulting weld joint, which was the desired quality characteristic. GMAW process parameters such as voltage, wire feed rate, and welding speed are optimized at three levels. Using ANOVA, the effects of each factor have been studied. It was found that the ideal set of parameters exists, and that the voltage is the most crucial factor. A confirmation test was performed to validate the results, and it was accompanied by a figure and tables.

Meteorology and Physics Analysis of Rail Car Fatality

When borax gets wet, it clumps. In this case, 76,000 pounds of previously wetted borax clumped on the inside of a rail car. The unbalanced load caused the rail car to fall on a yard worker, killing him. Tracking meteorological conditions in transit from Turkey to a port in Deleware, truck transit to a warehouse, handling at the warehouse, and rail transit to an interim transfer station was key to developing the origin and cause for the rail car derailing. There was evidence that clumping had rendered the product unusable by the end-user. However, this event occurred at the interim transfer station where the rail car product was transferred to trucks. This paper describes the process of determining how and where the borax absorbed moisture and shows physics that determined derailing was the result of an unbalanced load. This demonstrates the cause and effect of this event.