Switch Panel Research Articles

Numerical investigation of wheel-rail rolling contact characteristics and damage in a high-speed turnout switch panel under a large ramp

The damage pattern on a railway line under large ramp is more complicated than that of a standard railway line. In order to investigate the influence of the complex wheel-rail contact evolution in the turnout area on the service characteristics of the switch panel under a large ramp, this paper establishes an explicit FE model of the wheel-rail rolling contact on a 40‰ slope. The performance of a train crossing the turnout and the change in mesoscopic contact behavior is then analyzed under different operating conditions. The distribution rule for wear and fatigue damage to the switch rail under a large ramp is studied, with a regulation strategy proposed for improving the service performance of the switch rail based on the results. These show that there is an obvious cyclical incremental phenomenon on the mechanical behavior at the front end of the switch rail, with uneven abrasion distributed throughout the region. The increase in axle weight, speed and friction coefficient increases the stress concentration of the switch rail and exacerbates the damage. As the train passes through the switch panel, the service life of the switch rail can be significantly improved by reducing the traction.

Pioneering Maintenance Strategies for Enhanced Reliability of Low Voltage Switchboards

This study highlights the critical need for rigorous maintenance protocols, focusing on routine inspections, preventative measures, and timely corrective actions. Low voltage switch panels (PHB-TR) are vital for ensuring the efficiency and reliability of electricity distribution systems. Through systematic analysis of existing maintenance procedures and field evaluations across diverse setups, the research confirms that structured maintenance not only mitigates the risk of failures but also significantly reduces workplace accidents. The findings advocate for strict adherence to standard operating procedures and improved coordination among technicians, suggesting these strategies as global standards for enhancing the safety and functionality of electrical distribution networks. Highlights: Proper maintenance ensures optimal performance and reduces the risk of system failure. Adherence to applicable SOPs is crucial to prevent work accidents. Coordination and adherence to job distribution streamline work execution. Keywords: PHB-TR Maintenance, Split Switch Panel Maintenance, Low Voltage Split Switch Board

An investigation into vibration transmission patterns within metro turnout areas utilizing the structural sound intensity method

Urban rail transit turnout areas are notorious for inducing elevated environmental vibrations due to the complex interactions between wheels, rails, and supporting infrastructure. This paper establishes a comprehensive vehicle-track-tunnel-soil coupled dynamic model of a train traversing a turnout region. The intricate vibration transmission mechanisms within the turnout are explored through numerical simulation and visualization of vibration energy flow pathways. The structural sound intensity method facilitates the directional characterization of both transverse and longitudinal elastic waves emanating from the wheel-rail contact zone. Results reveal distinct propagation patterns between the switch panel and crossing panel, with more pronounced low-frequency energy backflow occurring in the switch panel. The transverse wave is found to dominate the elevated lateral vibrations observed along the tunnel walls. Frequency domain analysis maps the variation in energy flow directionality across one-third octave bands. The findings align closely with field measurement outcomes, validating the capacity of the approach to identify vibration "hot spots." Overall, this research enhances the theoretical comprehension of the complex interplay between diverse factors influencing turnout vibration transmission dynamics. The visualization technique proves instrumental in elucidating the critical mechanisms underlying the exacerbated environmental impact within these structurally intricate domains. Practical insights are distilled regarding turnout design strategies, vibration monitoring, and control methodologies to facilitate the mitigation of detrimental vibration effects.

Investigation of frictional rolling contact behavior in a switch panel considering traction load

The dynamic effects involved in wheel-rail interactions can be increased by the traction force potentially causing rapid degradation of turnout rails. A precise stress/strain analysis is essential for wheel-rail frictional rolling contact and the related degradation. Therefore, an explicit finite element method is established considering dynamic effects related to the contact. Furthermore, the frictional rolling contact solutions and related degradation with different traction coefficient in turnout are investigated. The results indicate that the effect of asymmetric excitation caused by traction force and geometric irregularities will lead to yaw motion of wheelset. The width of running band on the switch rail is increased as the top surface width of the switch rail increases. In addition, the contact patch on the switch rail will gradually shift forward compared to that on the stock rail, leading to excessive shear stress and increase of microslip. Meanwhile, the adhesion-slip distribution, uneven wear and severe plastic deformation during transition are recognized.

Analysis of Power Quality in Low Voltage Switch Panels in Real-Time Based on IoT Using the Fuzzy Logic Method

This far power quality analysis from the PHBTR monitoring system is still done manually. This condition creates several challenges in efficiency and accuracy in detecting and responding to changes in PHBTR power quality. With manual processes, collecting and analyzing data related to power quality can be time consuming, and there is the potential for delays in identifying disturbances or anomalies that could affect PHBTR performance. Therefore, in this research an innovative step was taken by applying the fuzzy logic method to simplify and increase the accuracy of automatic power quality analysis. From the analysis results, it was found that the power quality at the MCC4, GRL2, and CKG116 substations when viewed from voltage, current, frequency, and temperature, the three substations were at normal indications (91.32) and in good condition (76.32). However, the load balance quality of the three substations is still not balanced with load imbalance percentages of 110%, 52% and 17% respectively. This is because there are consumers in one phase using higher power than consumers in another phase, so a load imbalance will occur. This can be caused by differences in the use of electrical equipment or loads on each phase. Through this effort, it is hoped that significant improvements in the efficiency and responsibility of the PHBTR monitoring system can be achieved

Managing a multi-panel clinic with heterogeneous patients.

Primary care providers (PCPs) are considered the first-line defenders in preventive care. Patients seeking service from the same PCP constitute that physician's panel, which determines the overall supply and demand of the physician. The process of allocating patients to physician panels is called panel design. This study quantifies patient overflow and builds a mathematical model to evaluate the effect of two implementable panel assignments. In specialized panel assignment, patients are assigned based on their medical needs or visit frequency. In equal panel assignment, patients are distributed uniformly to maintain a similar composition across panels. We utilize majorization theory and numerical examples to evaluate the performance of the two designs. The results show that specialized panel assignment outperforms when (1) patient demands and physician capacity are relatively balanced or (2) patients who require frequent visits incur a higher shortage penalty. In a simulation model with actual patient arrival patterns, we also illustrate the robustness of the results and demonstrate the effect of switching panel policy when the patient pool changes over time.

A Story of Kinases and Adaptors: The Role of Lck, ZAP-70 and LAT in Switch Panel Governing T-Cell Development and Activation.

Specific antigen recognition is one of the immune system's features that allows it to mount intense yet controlled responses to an infinity of potential threats. T cells play a relevant role in the host defense and the clearance of pathogens by means of the specific recognition of peptide antigens presented by antigen-presenting cells (APCs), and, to do so, they are equipped with a clonally distributed antigen receptor called the T-cell receptor (TCR). Upon the specific engagement of the TCR, multiple intracellular signals are triggered, which lead to the activation, proliferation and differentiation of T lymphocytes into effector cells. In addition, this signaling cascade also operates during T-cell development, allowing for the generation of cells that can be helpful in the defense against threats, as well as preventing the generation of autoreactive cells. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. These early signals play a relevant role in triggering the development, activation, proliferation and apoptosis of T cells, and the negative regulation of these signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we will examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in these cellular processes.

Development of a Genset Monitoring and Control System via PLC DSE 7420 MK II on Automatic Transfer Switch (ATS) and Automatic Mains Failure (AMF) Panels at PT. XYZ

Listrik merupakan kebutuhan utama bagi PT. XYZ dimana harus selalu aktif dan kontinu ke semua bagian devisi PT. XYZ, terlebih dikhususkan pada devisi TI dimana harus selalu tersuplai sumber listrik karena terkait pemantauan server jaringan dan keamanan data-data perusahaan yang harus selalu dipantau non-stop. Adapun permasalahan lainnya yang penulis dapatkan terkait belum ada parameter sensor engine yang mengharuskan operator untuk standby di lapangan pada saat terjadi pemadaman listrik PLN. Selain itu, untuk menjaga keawetan dan ketahanan usia genset perlu maintenance agar pada saat jadwal yang ditentukan untuk pengecekan maka akan menampilkan notifikasi alarm pada modul PLC ataupun pada SCADA. Metode yang digunakan pada penelitian ini adalah metode research and development yaitu pendekatan sistematis untuk mencari solusi baru, pengembangan sistem/inovasi baru untuk meningkatkan kinerja dari sistem kontrol dan monitoring genset di PT. XYZ. Adapun tujuan dari penelitian ini adalah untuk pengambilan data file lama pada Deep Sea 4620 dijadikan sebagai evaluasi perubahan, untuk monitoring dan tampilan notifikasi alarm parameter sensor engine, menampilkan notifikasi peringatan maintenance genset. Dari hasil penelitian tersebut dapat disimpulkan bahwa PLC Deep Sea 7420 MK II memudahkan operator untuk pengoperasian dan monitoring jarak jauh tanpa langsung turun lapangan, mampu mengontrol perpindahan daya dengan cepat (0,7 detik) sehingga server pada gedung devisi IT selalu aktif dan terjaga tanpa adanya pemadaman pada beban, mampu mengontrol dan memonitoring parameter sensor genset secara real time baik dari modul PLC, aplikasi SCADA Suite dan monitoring dari aplikasi web SCADA, mengoperasikan perawatan pemananasan genset setiap hari jumat pada pukul 17.30 WIB dengan durasi 10 menit, menampilkan notifikasi maintenance fuel bahan bakar saat mencapai 790 jam setara dalam 1 bulan dan memberi kemudahan dalam melakukan pemeliharaan secara rutin dan selain itu dengan adanya jadwal berkala memudahkan operator untuk perawatan berkala setiap bulan.

The analysis of frictional rolling contact behavior and key affecting factors on uneven wear in a switch panel

To analyze the wheel-rail frictional rolling contact solutions and uneven wear in a switch panel, the wheel-rail frictional rolling contact model based on explicit integral algorithm considering coupling effect of structural vibration and contact mechanics, arbitrary contact geometry and nonlinear material is established. Then the wheel-rail explicit dynamics theory, unrepeatable saturated design, wear prediction method and data statistical processing methods are integrated as a method to figure out the key affecting factors, recognizing the influence of key factors on wheel-rail contact behavior and uneven wear in switch panel, including the contact force, the instantaneous and drastic changes of size, stress and microslip in contact patch and the distribution and magnitude of wear. The results of numerical simulations can provide guidance for investigation of contact mechanism and understanding of rail maintenance in switch panel.

Evaluation of dynamic derailment in a railway switch considering the longitudinal impacts caused by vehicle retarder

The operating conditions at the railway marshalling station are quite complicated, featuring low-speed turnouts, sharp curves, and vehicle retarders. Train derailments frequently occur in the switch panel. However, the passive safety and derailment behaviour considering the longitudinal impacts are still not clearly understood. With this aim in mind, a three-dimensional freight wagon-track (turnout) dynamic interaction model considering the impacts between wagons in longitudinal direction is established. The braking of the vehicle retarder on wheels is also simulated. The comparative analysis between the simulation results and field observation for the derailment is presented. The derailment limits along the switch are assessed based on 3D quasi-static analysis and numerical simulation. The results show that the longitudinal impact from the rear wagon can significantly increase the derailment risk when an empty wagon located in the middle passes through the vehicle retarder and switch. As the side wear depth of the switch rail increases to 5 mm, the vertical wheel rise at the front of the switch increases from 0 to 4.73 mm even though the other parameters keep an ideal level. Proper measures such as rail grinding and lubricating are suggested to be adopted for optimizing wheel-rail contact relationships and improving running safety.

Prediction of track settlement at high-speed railway transitions between embankment and bridge in the proximity of a turnout

It is well known that transition zones are subject to high differential settlement rates mainly due to the rapid change in track system stiffness as well as materials used. This problem is even more notable in high-speed lines where the dynamic effects are critical. In this paper, a methodology that combines large FE track models and vehicle-track MBS software with relatively low computational costs is proposed to calculate the long-term track behaviour in transition areas. The substructure dynamic characteristics are captured using an equivalent Lump Parameter (LP) model whose parameters are tuned against the FE track model to correctly reproduce the frequency response of the full track. The dynamic behaviour of the whole system is predicted using the in-house vertical vehicle-track software RailDyn. A settlement algorithm accounting for the development of hanging sleepers is then used in iterative simulations. A typical European high-speed transition zone between embankment and bridge is considered as a case study and various scenarios are analysed, including when a switch is located in proximity. Results show that the cement-bound reinforced and layered design considered creates a smooth increase of stiffness through the transition. On the other hand, localised differential settlement is predicted at the position of change in track stiffness, leading to an increase of stress in the ballast layer and a decrease in the layers beneath. The long-term soil behaviour at the switch panel is found to be completely dissociated from the behaviour at the transition when located at or more than 25 m from the bridge, as is the current practice.

Random analysis of dynamic wheel–rail interactions in the switch panel of a turnout with geometric tolerances based on the probability density evolution method

During train operation, the geometric tolerance in a turnout can be very random, posing a challenge for traditional deterministic vehicle-turnout coupling studies and for daily maintenance. In light of the above situation, a coupled vehicle-switch panel model with random geometric tolerances is proposed. These tolerances result from the discrepancy in relative height difference of rail tops between the straight switch rail and the curved stock rail, and from the gap between the straight switch rail and the curved stock rail in the closure part. The model takes rail flexibility into consideration. The probability density evolution method (PDEM) is applied to capture the resultant probability density function (PDF) of dynamic wheel–rail interactions. The Monte Carlo method is employed for verification of results obtained from the PDEM. The results show that stronger randomness of the vertical wheel force is induced compared with that of the lateral wheel force. The probabilistic range of the vertical wheel force is found to be around 50 kN on the straight switch rail side. Given the largest maximum mean value of rail displacement, it is found that the part of the straight switch rail with a top width of 40 mm requires significant attention.

Effects of flange wear on dynamic vehicle-turnout interaction

Long-term investigations have revealed incidences of severe flange wheel wear in the field. Slight changes in the profile shape will lead to changes in the geometric relationship between wheel and rail, hence affecting the dynamic wheel-rail interaction. The turnout is an essential piece of track equipment for carrying out train transfer or cross line operation. In turnouts, the rail profile changes throughout the structure, and the wheel load transfers from one rail component to the next, resulting in a complex wheel/rail relationship. This paper investigates the effect of flange wear on the wheel-rail interaction as the vehicle switches into the turnout track in a diverging movement. A coupling model for a high-speed flexible turnout and a multi-rigid vehicle is established, and the dynamic contact trajectories between wheel and rail, the vibration energy of the rail, the lateral wheel-rail force, rail wear, and car body driving stability are analyzed. The results show that the wheel transition position is shifted backward due to the flange wear, and a less sharp impact occurs with a worn flange profile during wheel load transition in the switch panel, which improves lateral wheel-turnout interaction and the rail wear. Worn flange profiles give a large flangeway clearance, which is not conducive to the smooth operation of vehicles in the diverging route of turnouts.

Effect of lateral misalignment defects of rail joints on dynamic derailment behaviour in railway turnouts

This study aims to investigate the mechanism of wheel jumping derailment in the railway switch panel after a freight wagon passes over a rail joint defect (RJD) situated before the switch. For this purpose, a 3D vehicle-track (turnout) coupled dynamic model that considers the elastic deformation of the rails and wheelsets has been established. Several extreme running conditions, including sharp curves, low-speed railway turnouts, lateral misalignment defects of RJs, and empty wagons are all considered in the simulation model. The vertical wheel rise limit for the railway switch panel is presented for the evaluation of a quasi-static derailment risk. The wheel-rail impact behaviour and the evolution of the derailment processes in the switch panel are revealed, and the effects of wagon load and misalignment width of RJ sections on the vehicle’s dynamic response and running safety are investigated. The results show that the root cause of the high derailment risk in the railway switch is a lower wheel rise limit at the front region of the switch rail when compared with the mainline. This dynamic derailment limit is sensitive to the car-body load and the misalignment width. Severe lateral defects of the RJ before the switch toe should therefore be avoided.

A finite element modelling approach for the numerical analysis of switch rail contact loading and cyclic profile degradation

A dynamic 3D finite element model for the calculation of profile degradation in the switch panel is presented. The model includes the contact between wheel and rail, as well as the contact between switch rail and stock rail to allow an elastic relative movement between the two rails. Break-outs of the switch rail tip can be facilitated by this relative movement and the stresses and strains at this interface are calculated. The profile degradation of the switch rail due to contact loading between wheel flange and switch rail is numerically simulated considering the cyclic plastic deformation of the rail material. The sliding wear is evaluated separately and superimposed to the geometrical change caused by the plastic deformation.

A multi-objective optimisation method of rail combination profile in high-speed turnout switch panel

This paper presents a multi-objective optimisation method considering the switch and stock rail profiles in the switch panel. Based on the non-uniform rational B-spline (NURBS) theory, a parameterised model of the measured turnout profile is constructed to determine the variables. This study selects the vehicle dynamic performance and wheel-rail contact damage as the objective function to establish a multi-objective optimisation mathematical model that is solved using NSGA-II. Overall performances of the measured profile and the optimised profile are compared and evaluated for two aspects, dynamic performance and wheel-rail contact damage. The following are the conclusions: The maximum lateral vibration acceleration of the axle box is reduced from 2.64–2.09 m/s2, which has a 20.83% decrease. Concerning wheel-rail contact damage, the maximum wear index is reduced from 13.46–11.47 N, the reduction is 14.78%. At the same time, the cumulative surface rolling contact fatigue (RCF) is reduced from 8.29×10−5–7.38×10−5. This article can provide a profile repair method for worn turnouts, which can maximise the comprehensive performance of the turnout within a limited amount of grinding, and can reduce the wheel-rail contact damage of the turnout while taking into account driving stability.

Investigation on train dynamic derailment in railway turnouts caused by track failure

Train derailments in low-speed railway turnout areas are very common due to poor track alignment and rail failures, and in extreme cases can lead to casualties and damage to infrastructure and railway vehicles. This study aims to explore the dynamic derailment behaviour caused by rail joint failures before the railway switch panel, and to understand the effects of crucial parameters on the operating safety of trains. To this end, a 3D dynamic coupled freight train-track simulation model is developed based on the MBS-FEM method. The model takes into consideration the lateral difference between rail joint sections that directly cause the wheel to rise. Flexible deformations of the rail and wheelset are modelled, and the derailment mechanism of wheel jumping and climbing in the railway switch panel is revealed. Results show that increasing the curve radius and distance between the rail joint and switch toe can effectively improve passing safety. When a sharp curve has to be placed before the switch panel due to site limitations, reducing the wheel-rail coefficient can also ensure better operating safety. This study indicates that the proposed MBS-FEM dynamic coupled derailment simulation model is able to efficiently evaluate the operating safety as a result of various wheel and track defects, and thus form a basis for providing a cost-effective platform for the future parameter optimization of railway tracks and vehicles.

Considering the interaction of switch and stock rails in modelling vehicle-track interaction in a switch panel diverging route

Vehicle-track interaction in a switch panel diverging route is studied with a focus on the way its components may interact in the lateral direction. Taking one of the cases of S&C benchmark as the base model, several variants of the co-running track model are considered. In the first series of simulation, the effect of the lateral separation of the switch rail and stock rail is investigated, showing that only small differences are found in terms of wheel/rail forces between a track model where both rails are coupled, and one where they are free to move with respect to one another. Only transient effects are visible at the beginning and at the end of the two-point contact on both rails. While small, these differences can have some influence in terms of rolling contact fatigue and wear prediction. In the second series of simulation, co-running track models are developed including the baseplate and taking into account such effects as switch rail/stock rail contact at the undercut plane and dry friction. Significant changes are observed in the load distribution within the switch panel. Conclusions should be consolidated through experimental field measurement and using more realistic track models, e.g. discretely supported rail beam models.

A novel three-dimensional wheel–rail contact geometry method in the switch panel considering variable cross-sections and yaw angle

Solving the wheel-turnout contact geometry is complex because the rail section is varying along its longitudinal position. Besides, a large yaw angle will occur, especially when the vehicle passes the switch panel in a diverging route. However, previous researches seldom considered the aforementioned factors simultaneously in performing wheel–rail local contact analysis. This paper therefore proposes a novel three-dimensional (3D) contact geometry method considering the combined effects of varying rail profiles and the yaw angle. This study uses S1002CN wheels and the switch panel of a 1:12 turnout as research objects to study the contact geometry, normal and tangential contact solution. The results indicate that the combined influences of rail profiles varying within the contact patch and the yaw angle on the contact solution are significant. The variable rail profiles obviously affect the position of the contact point. With a yaw angle, the normal gap, contact patch shape and stress distribution calculated by the novel 3D contact geometry method are asymmetric along the lateral and longitudinal directions, especially when the wheel flange contacts with a rail gauge corner. The proposed method can improve the accuracy of the wheel–rail contact solution and help predict rail damage in switch panels.

Assessment of derailment risk in railway turnouts through quasi-static analysis and dynamic simulation

Train derailments in railway switches are becoming more and more common, which have caused serious casualties and economic losses. Most previous studies ignored the derailment mechanism when vehicles pass through the turnout. With this consideration, this work aims to research the 3D derailment coefficient limit and passing performance in turnouts through the quasi-static analysis and multi-body dynamic simulation. The proposed derailment criteria have considered the influence of creep force and wheelset yaw angle. Results show that there are two derailing stages in switch panel, which are climbing the switch rail and stock rail, respectively. The 3D derailment coefficient limit at the region of top width 5 mm to 20 mm is much lower than the main track rail, which shows that wheels are more likely to derail in this area. The curve radius before the switch rail is suggested to be set as 350 m. When the curve radius before turnout is 65 m, the length of the straight line between the curve and turnout needs to be larger than 3 m. This work can provide a good understanding of the derailment limit and give guidance to set safety criteria when vehicles pass through the turnout.