Vertical Track Research Articles

Experimental and numerical investigations into torsional-flexural behaviours of railway composite sleepers and bearers

Abstract Fibre-reinforced foamed urethane (FFU) composite sleepers and bearers are safety-critical components installed in complex railway switches and crossings. Not only does they need to provide vertical track support, the composite sleepers and bearers must also endure longitudinal and lateral actions stemming from complex wheel and rail interactions. In reality, the railway bearers at crossing noses are susceptible to coupling torsional-flexural loading. The complex non-linear behaviours have never been investigated numerically nor experimentally. It is thus necessary to comprehend torsional-flexural behaviours of FFU composite sleepers and bearers through finite element and experimental approaches. 3D finite element modelling of FFU composite beams have been established to predict the non-linear coupling behaviours. Three specimens of FFU beams have been prepared for robust experiments under each load case. Our studies exhibit excellent agreement between numerical and experimental results. The ductile failure behaviours (post yield point) have been observed from the experiments. Considerable effects of load eccentricity on the flexure–torsion behaviours of the composite members can also be noted. In addition, the load-eccentricity curves have been identified to portray the non-linear behaviour of the railway components under coupling flexural and torsional loadings. The new insights considering their load–displacement relationships, modes of failure and damage, flexural and torsional interactions are the precursors for railway engineers to design and adopt FFU composite sleepers and bearers in practice where complex wheel/rail interface generally causes coupling torsional and vertical loading conditions.

Enhanced vertical railway track quality index with dynamic responses from moving trains

The conventional vertical track quality index (TQI) based on the standard deviation of longitudinal levels yields standardized railway track condition assessment. Nevertheless, its capability to identify problems is limited, particularly in the ballast and substructure layers when abrupt changes affect train-track interaction. Previous research shows that dynamic responses from moving trains via axle box acceleration (ABA) measurements can quantify abrupt changes in the vertical dynamic responses. Thus, this paper proposes a framework to design an enhanced vertical TQI, called EnVTQI, by integrating track longitudinal levels and dynamic responses from ABA measurements. First, measured ABA signals are processed to mitigate the influence of variation in measurement speed. Then, substructure and ballast-related features are extracted, including scale average wavelet power (SAWP) in the ranges 0.04 m-1 to 0.33 m-1 (substructure) and 1.25 m-1 to 2.50 m-1 (ballast). This enables identifying track conditions at different track layers. Finally, EnVTQI is determined by weight averaging between the conventional vertical TQI and the ABA features from moving trains. The performance of EnVTQI is evaluated based on 48 segments of a 200-m track on a Dutch railway line. The results indicate that EnVTQI helps to distinguish track segments that cause poor train-track interaction, which the conventional TQI does not indicate. EnVTQI can supplement the conventional TQI, improving the effectiveness of track maintenance decision-making.

Measurement and analysis of vibration responses due to subway transit in residential areas

The issue of building vibrations caused by subway operations has become increasingly prominent, significantly impacting residents' daily lives. This study investigates the vibration response of a residential area when the subway passing through, which involved the vibrations of the free field, the basement, and the nearby buildings. In addition, numerical simulation of building vibration by Etabs software was discussed. The free field vibration above the shield tunnel diminishes rapidly in the vertical track direction as the horizontal distance increases. However, the influence range of subway induced vibrations significantly expands when a basement is built adjacent to the subway. Data on building vibrations revealed the distribution of vibrations along the vertical direction and the vertical vibration amplification at the slab center due to local resonance. Interestingly, isolation designed for seismic loads also offers some benefits in reducing vertical vibrations. The numerical simulation results of the vibration response at the shear wall bottom show a certain degree of consistency with the actual measured results, but the attenuation of the vibration is faster, which may underestimate the vibration response of the building. The findings of this study provide valuable insights for understanding the impact of subway operations on surrounding buildings, optimizing subway and structural spatial layouts, and designing for vertical vibration control.

Vertical Track–Bridge Interaction in Railway Bridges with Ballast Superstructure: Experimental Analysis of Dynamic Stiffness and Damping Behavior

Realistic vibration predictions of railway bridges during high-speed train crossings require reliable dynamic input parameters for the applied calculation model. In particular, the dynamic stiffness and damping properties of the ballast superstructure for the mathematical consideration of the vertical track–bridge interaction (TBI) significantly influence the generated calculation results. However, due to a striking scattering of model-related characteristic values available in the literature, adequate and realistic consideration of the dynamic properties of the vertical TBI in vibration predictions is associated with considerable uncertainties. This uncertainness illustrates the need to determine experimental-based and reliable characteristic values. For targeted and isolated research of dynamic characteristics of vertical TBI, a unique large-scale test facility was developed at the Institute of Structural Engineering at TU Wien, which replicates a section of ballast superstructure on a railway bridge on a scale of 1:1 and excited to vertical movements. This paper presents the essential results and findings from the experiments, focusing on determining the ballast superstructure’s dynamic stiffness and damping characteristics, which can subsequently be implemented in practical applications for vibration predictions. As a result of the experiments, model-related dynamic stiffness and damping parameters are provided to describe the vertical TBI. In addition, the experiments are used to identify destabilization processes occurring in the ballast superstructure as a result of vertical vibrations. The investigations include the vertical TBI’s displacement and acceleration behavior and the track’s settlement behavior due to the entire structure’s vertical movements. These investigations allow for assessing the currently valid, internationally, and nationally normatively prescribed permissible accelerations for railway bridges due to train crossings. The conclusion is that short-term excessive vertical accelerations of the ballast superstructure caused by train passage do not destabilize the ballast bed or considerably change the track position.

Experimental, theoretical and optimization studies on multimode vibration reduction of floating raft system based on NES cells

Most of the studies on multimode vibration reduction of floating raft systems remain at the stage of theoretical analysis, while relevant experimental studies are rare. In this paper, an experimental setup for a scaled-down floating raft system is constructed. The vertical track nonlinear energy sink (TNES) cells are experimentally applied for the first time to suppress the multimode vibration of the floating raft system. To ensure the damping effect is not affected by additional mass, the TNES cells are always installed on the floating raft system. The TNES is able to achieve vibration suppression by allowing unrestricted movement of its vibrator. Two damping systems with different TNESs placement are proposed. Experimental modal analysis is performed on the floating raft structure to determine its response characteristics. Based on the results, different magnitudes of excitation force are applied to each order mode to effectively suppress the multimode vibration of the system. Meanwhile, the nonlinear system coupled with TNES cells is analyzed using the harmonic balance method (HBM) to obtain the approximate analytical solution. The system responses obtained from the analytical solution are compared with the experimental data results. The particle swarm optimization (PSO) algorithm is used to obtain the optimal parameters of the TNESs for vibration suppression. The results show that the multimodal vibration of the floating raft structure is effectively suppressed by the TNES cells in both experimental and theoretical analyses. The vibration suppression effect for all modes is significantly improved by the PSO algorithm. In conclusion, the research content of this paper provides a practical and feasible vibration suppression solution for the design of floating raft systems.

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.

Quantitative Detection of Vertical Track Irregularities under Non-Stationary Conditions with Variable Vehicle Speed.

Track irregularities directly affect the quality and safety of railway vehicle operations. Quantitative detection and real-time monitoring of track irregularities are of great importance. However, due to the frequent variable vehicle speed, vehicle operation is a typical non-stationary process. The traditional signal analysis methods are unsuitable for non-stationary processes, making the quantitative detection of the wavelength and amplitude of track irregularities difficult. To solve the above problems, this paper proposes a quantitative detection method of track irregularities under non-stationary conditions with variable vehicle speed by order tracking analysis for the first time. Firstly, a simplified wheel-rail dynamic model is established to derive the quantitative relationship between the axle-box vertical vibration and the track vertical irregularities. Secondly, the Simpson double integration method is proposed to calculate the axle-box vertical displacement based on the axle-box vertical acceleration, and the process error is optimized. Thirdly, based on the order tracking analysis theory, the angular domain resampling is performed on the axle-box vertical displacement time-domain signal in combination with the wheel rotation speed signals, and the quantitative detection of the track irregularities is achieved. Finally, the proposed method is validated based on simulation and field test analysis cases. We provide theoretical support and method reference for the quantitative detection method of track irregularities.

A vertical track nonlinear energy sink

Eliminating the effects of gravity and designing nonlinear energy sinks (NESs) that suppress vibration in the vertical direction is a challenging task with numerous damping requirements. In this paper, the dynamic design of a vertical track nonlinear energy sink (VTNES) with zero linear stiffness in the vertical direction is proposed and realized for the first time. The motion differential equations of the VTNES coupled with a linear oscillator (LO) are established. With the strong nonlinearity considered of the VTNES, the steady-state response of the system is analyzed with the harmonic balance method (HBM), and the accuracy of the HBM is verified numerically. On this basis, the VTNES prototype is manufactured, and its nonlinear stiffness is identified. The damping effect and dynamic characteristics of the VTNES are studied theoretically and experimentally. The results show that the VTNES has better damping effects when strong modulation responses (SMRs) occur. Moreover, even for small-amplitude vibration, the VTNES also has a good vibration suppression effect. To sum up, in order to suppress the vertical vibration, an NES is designed and developed, which can suppress the vertical vibration within certain ranges of the resonance frequency and the vibration intensity.

Pilot study for three-dimensional cephalometric Enlow's counterpart analysis: Vertical track. Two-dimensional and three-dimensional comparison.

The introduction of cone beam computed tomography (CBCT) in dentistry has given orthodontists the possibility of studying craniofacial structures in three dimensions. Despite the possibility to obtain lateral cephalograms synthesized from CBCT, this approach still does not provide a fully three-dimensional evaluation of the patient's anatomy. While there has been some success in adapting traditional two-dimensional cephalometric analyses to three dimensions, the specific application of Enlow's cephalometric analysis using CBCT remains unexplored. This pilot study aims to introduce a novel approach for performing Enlow's vertical track analysis using CBCT images. Eighteen CBCT images of skeletal Class I (ANB = 2 ± 2) subjects (12 males and 6 females, aged from 9 to 19 years) with no history of previous orthodontic treatment were selected. For each subject, 2D Enlow's vertical track analysis was performed on lateral cephalograms extracted from the CBCT images, and separately, 3D vertical track analysis was directly performed on the CBCT images. To validate the proposed method, we compared the differences between the posterior vertical counterpart (PVC) and the middle vertical counterpart (MVC), as well as between the middle vertical counterpart (MVC) and the anterior vertical counterpart (AVC), as obtained from both the two-dimensional and three-dimensional analyses. The Kolmogorov-Smirnov normality test was applied for each variable to check whether data were normally distributed and a paired Student's t-test was performed. The level of statistical significance was .05. The comparison between three-dimensional PVC-MVC (-0.43 ± 0.37 cm) and two-dimensional PVC-MVC (-0.53 ± 0.36 cm) revealed no statistical difference (P = .27). Similarly, no significant difference (P = .28) was observed between two-dimensional MVC-AVC (-0.56 ± 0.34 cm) and three-dimensional MVC-AVC (-0.47 ± 0.37 cm). The method proposed by this study to realize the vertical track analysis on 3D images is valid and superimposable on that described by Enlow on lateral cephalograms.

Field assessment of different tamping operations for newly constructed or renovated railway tracks

ABSTRACT The tamping process is crucial for correcting geometric irregularities on railway tracks, especially on newly constructed or renovated tracks that are more susceptible to accumulating defects. Recent studies have demonstrated that multiple insertions of tamping tines lead to greater ballast compaction and improved lateral resistance of the track. However, further evaluation is necessary to assess their impact on other important track parameters. This study evaluated single and multiple insertions to determine which would promote more effective maintenance for newly built or renovated track conditions, focusing on geometry correction, track structural behaviour, and potential ballast degradation. These tamping methods were tested in a heavy haul line, showing that multiple insertions improved geometric quality, increased lateral resistance, and enhanced vertical track stiffness without causing significant ballast degradation. Therefore, using multiple insertions is recommended for newly built or renovated tracks to enhance geometric quality and structural behaviour, providing a more effective maintenance solution.

Railway track vertical irregularities classification based on vehicle response using machine learning method

The common method of railway track irregularities assessment currently used, based on track geometry measurement data, is expensive to run, disrupts regular train services, and shows poor correlation with the actual vehicle response when running on a given track section. Vehicle response-based track irregularities assessment methods aim to overcome the shortcomings of geometry measurement-based methods. One of the possible methods is to establish the correlation between track geometry and vehicle response statistically using machine learning. Classification algorithms have been used in previous research for categorizing track sections into discrete classes. In this paper, in addition to discrete classification, the probability for which a track section is categorized as a certain class is presented. Testing results of the trained machine learning classification model showed high accuracy, precision, and recall. The results indicated that this method is suitable for classification of the vertical track irregularities. Further testing was performed with shifted classification threshold. The finding showed that the classification model’s precision and recall could be adjusted by shifting the classification threshold. The result of this study highlights the potential of machine learning classification usage for track irregularities assessment.

The effect of ballast moisture content and fouling index on railway track settlement

A primary function of railway ballast is to maintain vertical track geometry, however over time it becomes contaminated with fines which reduce its ability to free-drain. Then, in the presence of moisture, the individual particles have greater scope for rearrangement thus leading to increased track settlement. This behaviour has received limited studied from a differential settlement viewpoint despite track geometry being the dominant metric used for scheduling railway maintenance. Therefore this paper presents a novel numerical modelling approach capable of simulating the effect of ballast fouling and moisture content on the evolution of track geometry. First the model is presented, which uses a 2.5D finite element approach with perfectly matched layers to simulate static and dynamic stress fields from trains. Non-linear track-soil effects are considered and loading is applied using a multi-body vehicle with train-track coupling. Differential track settlement is calculated in an iterative manner, being updated after every train passage. It is used to perform four analyses, the first of which is to investigate the effect of ballast fouling considering dry conditions. Next the effect of moisture of fines is studied. Then, the effect of earthwork stiffness and train speed is analysed. It is shown that elevated levels of ballast fouling lead to faster deterioration in track geometry, particularly in the presence of moisture. When the ballast is heavily fouled and the moisture of fines is high, rapid deterioration occurs. In contrast, when the ballast is kept dry, the increase in degradation rate for fouled ballast is limited. Higher train speeds and lower earthwork stiffness’s make this effect more pronounced.

Dynamic Stress Response in a Novel Prestressed Subgrade under Heavy-Haul Train Loading: A Numerical Analysis

To explore the dynamic transient characteristics induced by passing heavy-haul trains in newly-developed prestressed subgrade, two three-dimensional finite element models were constructed in the time domain using ABAQUS software. These models are categorized as train-track-prestressed subgrade and train-track-unreinforced subgrade. The numerical models also incorporated the vertical track irregularity commonly found in heavy-haul railways. The investigation aims to discern the dynamic stress response differences in both types of subgrades under three distinct train axle loads. Model validation occurred through comparisons with field tests gathered from various heavy-haul railways in China, as well as analogous numerical simulation cases. The findings indicate that track irregularity results in an asymmetric distribution of dynamic stress on the subgrade surface beneath both left and right rails, aligned transversely with the subgrade centerline. Additionally, this asymmetry is notably pronounced. The peak dynamic stress on the subgrade surface beneath the rails for both subgrades increases with escalating train axle loads. However, the prestressed reinforcement structure (PRS) effectively modulates this phenomenon, with the controlling advantage intensifying as train axle load increases. The average dynamic stress level in the prestressed subgrade is marginally lower than in the unreinforced subgrade within the roadbed layer beneath rails. Furthermore, train axle loads amplify the variation level of dynamic stress in the subgrade. However, the variable coefficient of dynamic stress in the prestressed subgrade is less than in the unreinforced subgrade, suggesting that PRS contributes positively to maintaining subgrade dynamic stability. In terms of the longitudinal distribution of peak dynamic stress, both subgrades exhibit normal distribution at varying depths within the roadbed layer. Lastly, the additional dynamic stress in prestressed steel bars also rises with increasing train axle loads. Nonetheless, it remains substantially lower than the static target pre-tensile stress. Moreover, the dynamic responses of prestressed steel bars in different rows attenuate as depth increases away from the subgrade surface. In summary, the study establishes that PRS significantly enhances the dynamic stability of railway subgrade.

PEM-based random vibration analysis under service-braking conditions on an irregular track

PurposeAccording to relevant research, non-uniform speed has a significant impact on the vehicle-track systems. Up to now, research work on it is still very limited. In this paper, the PEM is adopted to further transform it into a deterministic process to solve the vehicle’s problem of running at a non-uniform speed.Design/methodology/approachThe multi-body vehicle model has 10 degrees of freedom and the track is regarded as a finite long beam supported by lumped sleepers and ballast blocks. They are connected via linear Hertz springs. The vertical track irregularity is a Gaussian stationary process in the space domain. It is transformed into a uniformly modulated nonstationary random process in the time domain with respect to the non-uniform vehicle speed. By solving the equation of motion of the coupled vehicle-track system with the pseudo-excitation method, the pseudo-response and consequently the power spectral density and the standard deviation of the structural response can be obtained.FindingsTwo kinds of vehicle braking programs are taken in the numerical example and some beneficial conclusions are drawn.Originality/valueThe pseudo-excitation method (PEM) was used to perform the random vibration analysis of a coupled non-uniform speed vehicle-track system. Transforming the track irregularity into a uniformly modulated nonstationary random process in time domain with respect to the non-uniform vehicle speed was undertaken. The pseudo-response of the coupled system is solved by applying the Newmark algorithm with constant space integral steps. The random vibration transfer mechanism of the coupled system is fully discussed.

Measuring vertical track irregularities from instrumented heavy haul railway vehicle data using machine learning

This paper proposes a data-driven approach to estimating geometric track irregularities from instrumented railway vehicle (IRV) data. Machine learning is used to find the nonlinear mapping between IRV data and track irregularities. A dynamic model of the BRA1 railway vehicle was used to generate an artificial dataset that contains variables that are measured by the real BRA1 IRV and other variables measured by IRVs found in the literature. An extensive data analysis step was done to verify if the current instrumentation of the BRA1 IRV is sufficient for obtaining both lateral and vertical track irregularities. Feature engineering based on wagon movements, signal integration and time domain statistical metrics were applied to extract features and then the best features were selected using a wrapper method. Eight different regression ML models were trained and optimized after the feature selection using Optuna. The results show that, with the current instrumentation of the BRA1 IRV, obtaining lateral track irregularities is unlikely due to low correlation, however, vertical irregularities can be obtained with a root mean squared error (RMSE) of 0.556 mm. With postprocessing, the RMSE was further reduced to 0.410 mm.

Creation Incentives, Market Competition and We-media Intellectual Property Output: An Empirical Analysis Based on the Creation Incentive Policy of the “New Star Plan Vertical Track” at Station B

<p>Based on the in-depth understanding of the “new star plan vertical track” policy of station B, this paper uses Python to crawl the video data of station B from 2016 to 2020, and uses the fixed effect model to test the impact of the creative incentive intensity of station B on the competition in the we media market and the output of intellectual property rights. The results show that there is a significant positive impact between the creative incentive intensity and the intellectual property output of we media. The higher the creative incentive intensity is, the higher the intellectual property output benefit of we media is. Moreover, the increase of creative incentive intensity can weaken the degree of market competition. That is to say, it is obvious that the flow resources tend to get videos with high creative incentive subsidies, and there is a “siphon effect”. Based on the theme of government subsidy and enterprise innovation incentive, this paper puts forward the empirical analysis of the creative incentive intensity and we media market competition, intellectual property output for the first time. Through the calculation method of government subsidy incentive and enterprise output effect, it has strong pioneering and rigorous.</p>

Real-Time Measurement of Track Irregularities Using an Instrumented Axle and Kalman Filtering Techniques

Abstract A model-based methodology for the estimation of both lateral and vertical track irregularities is presented. This methodology, based on Kalman filter techniques, was developed for an independent and compact measuring system comprising an instrumented axle equipped with a limited set of low-cost sensors: a 3D gyroscope, a linear variable differential transformer (LVDT) distance sensor, and an encoder. The instrumented axle can be used on any railway vehicle traveling at moderate forward speed to provide measurements in real-time. The proposed methodology, combined with the instrumented axle, enables precise and prompt measurement of track irregularities. An experimental campaign carried out on a 1:10 scale track facility at the University of Seville validated both the system and the methodology. In the testing, 80 m of scaled track was measured at an operational speed of V = 0.65 m/s in just 2 min. Simulation estimates for track irregularities compared against the measured data from the testing showed a good performance of the proposed methodology, with maximum errors of 0.45 mm in the short wavelength range D1, the range most influential to vehicle dynamic behavior.

Performance Evaluation of a Combined Transition System in Slab-Ballasted Railway Track Using a Vehicle-Track-Substructure Interaction Model

Abrupt stiffness variations along the railway track may increase the geometrical and mechanical defects of railway lines. The conjunction points of a railway track with concrete and ballast pavements, which are called slab-ballasted track transitions, are one of the main areas where vertical track stiffness changes sharply. Therefore, the potential benefits of a combined transition system along the slab-ballasted transition, made of an approach slab and additional rails, are studied in this paper. For this purpose, a vehicle-track-substructure interaction model, which included three main segments of the railway track (slab track, transition zone, and ballasted track) was programmed based on the finite element method. A test line with the mentioned combined transition system was built to measure the railway track responses through field study. Then, the three-dimensional (3D) numerical model was validated using the results obtained from the experimental tests. Afterwards, a number of parametric studies were performed to analyze the dynamic responses of the combined transition zone. The results indicated that this type of transition system promotes a smoother stiffness transition between the slab track segment and the ballasted track segment by making the transition in three gradual steps. The track displacements in the analyzed case-study gradually increased by about 22%, 28%, and 34% along the combined transition zone in the junction points of the slab and ballasted tracks.

The random dynamic performances of EMUs with polygonal damages

Polygonalization is a typical non-uniform wear phenomenon that affects the performance and comfort of the vehicle/track system. Therefore, the vehicle system performance could be strictly troubled by polygonal damage close to the wheel circumference at the wheel/rail contact. A 3D vehicle/track an EMU type train consisting of 8 coupled vehicles model has been established. The coupled model car body and bogie frame are considered rigid and integrated with the flexible wheelset, rail, and slab track to investigate the elastic deformation caused by the impact load induced by the wheel polygonalization. The flexible track can be incorporated into the multi-body vehicle model using the movable reference frame formulation. Uncertainty parameters are presented, such as passenger weight, wind force, coefficient friction, and suspension variation. The proposed research is validated based on the existing research work and shows excellent agreement. The simulation result deliberated the vertical wheel-rail force, wheelset acceleration, rail acceleration, rail displacement, and slab track acceleration. The results of this study show that as the wheel polygonal damage amplitude increase, the value of wheel/rail normal forces and the dynamic vibrational response of the wheelset axle increase. Additionally, polygonal wear-induced impact stresses may cause the wheelset axle to resonate. When wheel polygonal damage amplitude and uncertainty parameters are corporate into the system dynamics, the maximum magnitude of the wheelset, rail, and slab track acceleration increases. Besides, the train failure degree is comparable to the polygonised wheel harmonic order, defect parameters, and amplitude of out-of-roundness.

First developments towards producing inductive magnetic sensors using state-of-the-art photolithography techniques

Inductive magnetic sensors are needed for tokamak operation to provide the low-frequency (LF) measurements leading to the equilibrium reconstruction and to monitor the higher frequency (HF) instabilities; the HF magnetic sensors are often also used as a back-up to the LF ones. For the HF inductive magnetic sensors (fluctuation measurements), we need to minimize the self-inductance (L SELF) provided that the effective area (N A EFF) remains sufficiently large, typically requiring L SELF < 100 μH and N A EFF ∼ 0.01 m2. For the LF inductive magnetic sensors (equilibrium reconstruction), the only physics-based design criteria are that of maximizing N A EFF > 0.10 m2, essentially independently of the resulting L SELF. Due to these rather different measurement specifications, it is quite the common case that different sets of LF and HF inductive magnetic sensors are used, which significantly complicates the R&D activities and the ensuing manufacturing processes.Starting in 2007, our group at the Swiss Plasma Centre at the Ecole Polytechnique Fédérale de Lausanne (EPFL) has originally developed the Low-Temperature Co-fired Ceramic (LTCC) technology for producing inductive magnetic sensors, this technology being exceptionally suitable for operating temperatures up to ∼1'000C in very harsh environmental conditions. The similarly named High-Temperature (HTCC) technology uses the same processes but different materials, and it is then suitable for operating temperatures up to ∼1'600C. ITER will have about ∼250 such LTCC sensors, of EPFL design and prototyped at the EPFL, but manufactured by a commercial entity to technical specifications lower than those achieved at the EPFL in terms of track width, track separation and overall manufacturing yields.While state-of-the-art in 2007, the LTCC and HTCC technologies are now at least 20 years old and new processes have been developed for commercial applications, essentially based on different photolithography (PL) techniques. Recent, and already industrialized, advances in microfabrication using PL techniques offer the possibility to create more compact and optimized designs starting from current industrial standards, therefore extremely facilitating the very costly lab-to-fab step of production, namely all the activities that lead from the ideas in the lab to the actual (industrialized) fabrication. Our goal is to continue to push the frontier of magnetic sensors, bring a commercially viable design that can be used in tomorrow's scientific projects, such as nuclear fusion and astronomy/astrophysics (for instance, in the new generations of miniaturized satellites).The main advantage of the PL techniques is that a much smaller track width (dd1) can be achieved, down from the routine dd1 = 100 μm of the EPFL LTCC sensors (for ITER: dd1 = 400 μm) to dd1 < 10 μm. A smaller dd1 allows to pack more planar winding loops (m) enclosing a larger area over a smaller geometrical surface. Therefore, PL coils can have a lower self-inductance L SELF ∝ m2 while having the same effective area N A EFF ∝ m compared to coils manufactured by other more common technologies. Therefore, with PL techniques a similar design could be used for both HF and LF applications, the difference simply being the number of stacked-up layers (n) used to make-up the entire sensor.In this paper we will present the first developments towards the production of inductive magnetic sensors using PL techniques. Whilst providing the possibility of designing better performing and more compact sensors, the introduction of PL techniques in the manufacturing processes for inductive magnetic sensors has uncovered new limitations and obstacles, such as the required vertical track thickness that is poorly suited for the existing deposition techniques, the need for stacking up multiple wafers and the connection between the sensor and the in-vessel cabling.