Digital and Data-Driven Maintenance of Switching Systems

© Fraunhofer IVI

Outset

Switches are key elements of the rail network: They enable high capacity and operational safety, but are also among the most costly and heavily used infrastructure components. At Deutsche Bahn (DB), switch malfunctions account for about 20 % of infrastructure failures that cause train delays and are the second-largest source of errors after signaling systems. About 30 % of the switches are considered outdated. To date, interval-based maintenance has been the norm, with inspections and maintenance carried out regardless of the actual condition of the switches.

 

Project Aims

  • einen robusten, störungsfreien Betrieb von Weichen zu gewährleisten und notwendige Eingriffe zu minimieren,
  • Investitionen in Weichentechnik und Instandhaltung durch innovative digitale Technologien effizienter einzusetzen,
  • praxistaugliche Migrationsszenarien für eine flächendeckende Einführung abzuleiten und wirtschaftlich zu bewerten.

The project, commissioned by the German Center for Rail Transport Research (DZSF) through the Federal Railway Authority (EBA), is developing a comprehensive concept for the digital and data-driven maintenance of track switches. It supports the transition from corrective and preventive maintenance to condition-based and predictive maintenance and aims to

  • ensure robust, trouble-free operation of switches and minimize necessary interventions,
  • make more efficient use of investments in switch technology and maintenance through innovative digital technologies,
  • and derive and economically evaluate practical migration scenarios for widespread implementation.

 

Approach

The project is divided into four work packages that build on one another and are carried out in close coordination with DB InfraGO, DB Systemtechnik, and other industry partners.

Work packages

Potentials and requirements

© Fraunhofer IVI
Requirements analysis for a digital maintenance concept for switches.

In the first work package, technological and organizational approaches for digital and data-driven switch maintenance will be identified, evaluated, and classified according to their level of maturity. The study will examine, among other things, condition monitoring via track-side sensors, predictive maintenance using AI-based predictive models, digital twins for simulating switch conditions, automated maintenance robotics, IoT-based component networking, as well as mobile applications and augmented reality to support maintenance personnel on-site.

At the same time, malfunctions and faults in the switches are systematically recorded and analyzed. Switches are viewed as an integrated system comprising the superstructure, signaling and telecommunications (LST), and electrical engineering disciplines. Using FMEA (Failure Mode and Effects Analysis), causes, frequencies, effects, and criticality levels are assessed for all switch components. Data from the operators’ fault and maintenance systems provide the empirical basis. The goal is to derive the relevant condition parameters for each component and to verify whether these can be captured using current or future sensor technology.

Building on this, a comprehensive requirements analysis is conducted along the entire information flow: from data acquisition through transmission, storage, and visualization to the planning, control, and documentation of maintenance measures. This analysis also takes into account IT security, data protection, compliance with railway-specific standards, user-friendliness, and scalability.

Development and validation of a sensor concept

Schematic representation of the sensor concept.
© Fraunhofer IVI
Schematic representation of the sensor concept.

To facilitate the transition to data-driven maintenance strategies, a holistic sensor concept is being developed that is informative, robust, cost-effective, requires as little maintenance as possible, and is easy to implement during ongoing operations. It combines sensor technology for all three switch maintenance disciplines: acceleration and vibration sensors, as well as acoustic, laser, and environmental sensors for the track superstructure; current, pressure, and limit position sensors for the LST; and temperature, humidity, and power measurements for electrical systems and switch heating.

The development work is carried out iteratively: Based on the FMEA from WP1, an initial sensor selection is made and validated in operation. A baseline is established by comparing the data with conventional inspection data; deviations between sensor diagnoses and actual malfunctions are fed back into the analysis via a feedback loop, leading to continuous refinement of the sensor selection, algorithms, and threshold values. In this way, the system gradually evolves from supplementary monitoring to demand-driven maintenance.

The AXO X1 sensor system, which measures triaxial acceleration, temperature, and humidity, serves as a practical reference solution.

Definition of a maintenance plan

© Fraunhofer IVI
Schematisc representaiton of the maintenance plan.

The digital maintenance concept combines the collection of relevant data and metrics with the detection, prediction, and assessment of failures, the optimized planning of corrective actions, as well as the management of their implementation and evaluation of their impact. The solutions can be technological, such as diagnostic and predictive methods, sensor technology, or mobile tools, and organizational, such as process improvements, standardization, and a strategic mix with conventional methods.

The starting point is DB InfraGO’s current, scheduled preventive maintenance program. This approach is highly predictable and compliant with regulations, but it does not always take the actual condition of the infrastructure into account and requires a significant allocation of resources in the event of individual failures.

In the next step, the data-driven approach will be implemented in parallel with the existing regulatory framework: Interval-based maintenance will be fully retained, while continuous condition data will also be analyzed. This reduces unplanned corrective interventions, enables prioritization within the specified intervals, and builds trust among staff through the direct comparison of both approaches. In the long term, the goal is predictive planning, in which the optimal maintenance time is determined based on the remaining useful life (RUL). Trend analyses, anomaly detection, degradation models, and AI-based forecasts provide the foundation; feedback loops after each intervention continuously adjust sensor selection, threshold values, and planning models, thereby creating a robust basis for decision-making in operational, tactical, and strategic planning.

Derivation and evaluation of migration scenarios

© Oliver von Sperber | AXO Track GmbH
Sensor system installation.
© Oliver von Sperber | AXO Track GmbH
The sensor system installed on the tracks.

To implement the concept in practice, migration scenarios that vary by location and time are being developed and evaluated. On the high-performance network, fully renovated corridors (Berlin-Hamburg) equipped with new switches are ideal for an early rollout, as extensive sensor systems can be installed there and the condition of the infrastructure can be monitored starting from a defined baseline. In the supplementary network, cost-effective sensors that can be retrofitted quickly hold particularly high potential, because the advanced age of the infrastructure, poor accessibility, and limited budgets there often result in high disruption costs.

Project details

  • Term: ca. 30 months
  • Commissioned by: On behalf of the German Center for Rail Transport Research (DZSF) at the Federal Railway Authority (EBA)

Partners

The consortium partners combine practical know-how, the expertise of sensor manufacturers, and scientific methods:

  • AXO Track GmbH – Development and provision of the IoT sensor systems
  • Fraunhofer IVI – Data analytics, AI methods and maintenance planning expertise
  • Jörg Horn Weichentraining – Expertise in Switching Technology and Practical Application
  • IZP Dresden mbH – RAMS, reliability, FMEA and lifecycle costs