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Tag: Troubleshooting

Troubleshooting – Our solutions

Structural repair area of a railway vehicle underframe during inspection and analysis, showing exposed metal sections, weld seams, and protective coverings.

Sustainable repair solution for crack issues on aluminum car bodies

Customer: SBB, Switzerland

Project tasks

  • Review and analysis of existing documentation
  • Specification of FE calculation and planning of measurement runs
  • Performance of FE analyses to identify the cause of damage
  • Performance and evaluation of measurement runs to validate calculations
  • Development of a constructive repair solution, including verification
  • Creation of manufacturing documentation (drawings, parts lists, CAD models)

Our approach

SBB operates a total of 223 multiple units of a certain type in several sub-fleets, which were procured in several tranches between 2004 and 2023. In 2018, cracks were first detected in various sub-fleets at the weld seam between the underframe and the end wall. Due to their frequency, the cracks could not be attributed to individual overload events such as collisions. A Finite Element (FE) analysis carried out in 2018 determined that the cracks were fatigue-related and were caused by improperly executed welds. During the subsequent corrosion remediation, these weld seams were repaired with the required seam cross-section and weld pool protection. However, cracks have reappeared in the joints that had already been repaired. This recurrence shows that the damage mechanism was not fully clarified in the initial FE analysis and that the earlier repair approach was therefore insufficient.

PROSE proceeded systematically in five steps: First, we reviewed and analysed all existing documents, findings and vehicles. This was followed by the specification and planning of FE calculations and measurement runs to identify the cause of the damage. Next, FE analyses and sensitivity studies were used to evaluate the actual condition mathematically and validate the results with real measurement data. Based on these findings, we developed a constructive repair solution and provided a verification report together with the complete manufacturing documentation.

Customer benefit

Through systematic damage analysis using FE calculations and real measurement data, SBB obtains a validated understanding of the root cause for the recurring cracks on this type of trains. Based on these insights, PROSE has developed a technically proven repair solution that ensures the long-term structural integrity of the vehicles and extends their service life to at least 32 years.

The repair solution also reduces lifecycle costs compared to a new build and minimises operational downtime, by addressing the relevant weak points. With complete verification and manufacturing documentation, SBB can efficiently integrate the measures into its maintenance programme and continue operations with high availability.

 

   

Operating load measurement and assessment of fracture mechanics

Customer: RAlpin AG, Switzerland

Project tasks

  • Operating load measurement
  • Wheelset shaft calculation
  • FE calculation
  • Fracture mechanics assessment

Our approach

The customer required two fracture mechanics analyses. On the one hand, the aim was to investigate what causes cracks to form on the back of the wheel flange and which factors contribute to crack growth. On the other hand, there was a need to provide a mathematical basis for the specified inspection interval for the wheelset shafts. Real operating load data should be used as the basis for the fracture mechanics investigations of PROSE.

PROSE carried out an unaccompanied measurement to record the operating loads on the routes travelled. For this purpose, a measuring system was installed directly on a bogie frame. This recorded the position of the vehicle combination over several days using an associated GPS antenna as well as the lateral and vertical acceleration and the rotational speed of the bogie using appropriate sensors. The measurement signals were continuously sent to a central storage unit via the mobile phone network. The real operating loads measured in this way formed the basis for the subsequent fracture mechanics tests.

The wheel disc cracks were investigated using two wheel types used by the customer. The load on these wheel types was simulated using MBS simulation based on the real load data.

To assess the fracture mechanics of the wheelset shafts, a wheelset shaft calculation according to EN13103-1 was carried out in a first step for orientation and to assess the general utilisation of the wheelset shaft. In a second step, cyclic crack propagation calculations were carried out at the critical shaft positions (positions with the highest bending stresses).

Customer benefit

Our fracture mechanics tests confirmed that the cracks in the wheel discs were not caused by braking behaviour or contact with the wheel control arm. Residual stresses were identified as a possible cause of the crack propagation. However, the fracture mechanics assessment of the wheelset shaft also confirmed that the existing test interval provides sufficient safety.

PROSE’s neutral and independent position and in-depth technical understanding gave the customer a solid starting point for further investigations. By utilising data from operational load measurements, the investigation could be tailored to real operating conditions, improving the quality of the results and increasing the client’s confidence in the findings. PROSE’s unique railway engineering expertise and extensive experience with rolling stock provides a bespoke, unbiased analysis that supports effective decision-making and long-term asset management.

 

 

Wear monitoring for meter gauge railway

Customer: Montreux-Oberland-Bahn (MOB), Switzerland

Project tasks

  • Project management
  • Concept development
  • System integration

Our approach

The Montreux Oberland Railway (MOB) was faced with a challenge when it was suddenly confronted with increased noise and heavy wear on the wheels and rails of a large number of vehicles in its fleet. Various vehicles showed unexpectedly high signs of wear.

PROSE carried out two days of acoustic measurements on a vehicle travelling on the MOB network. We used wireless microphones that were magnetically attached under the car body on each side of the train. The acoustic signals were sent wirelessly to a laptop inside the vehicle. With the help of special acoustic software, these acoustic signals were transferred from the time domain to the frequency domain in real time. Based on the amplitudes in certain frequencies, the problem of noise and wear in certain curves of the network could be localised. Additional measurements on the rails showed that the wheel flange lubrication on the rail was inadequate and was causing noise and wear. After manually lubricating around 10 curves on the 45 km network, the wear disappeared completely and the noise was reduced.

Customer benefit

The MOB had to reduce its services as the wear and noise pollution were no longer acceptable. After the problem was analysed and localised by PROSE-experts on the MOB network within a day of the measurement, noise and wear were reduced to a minimum and the MOB was able to resume regular operations.

 

  

3rd party assessment of exterior camera installation

Customer: MTR Tech, Sweden

Project tasks

  • Assessment of proposed and installed solutions of camera installation
  • Highlighting risks and deviations from industry standards and recommendations

Our Approach

MTR has operated and maintained the X60 Coradia fleet on behalf of the Stockholm Region until 2024. The region has ordered installation of cameras from Alstom to support the drivers and improve visibility around the door-area, particularly on platforms with curved tracks.

PROSE has extensive experience in mechanical and electrical design as well as design processes, especially in adhesive bonding. Based on our expertise, an iterative assessment process has taken place to assess the proposed and installed solution. It includes recommendations in line with industry best practice for both mechanical design and bonding – as well as design and processes – in accordance with EN17460.

Customer benefit

​Adding additional equipment to an existing fleet without impacting the basic design requires experience and know-how about production methods and the original design. With PROSE as an independent assessor, the client received an independent assessment of the proposed and installed solution as well as the identification of potential short- and long-term risks in the proposed design of both the bonded joints and the mechanical parts.

 

      

Gearbox investigation on vehicles

Project tasks

  • Project management
  • Create a feasibility study
  • Test proposals based on the preliminary study
  • Evaluation from tests
  • Recommendations

Our Approach

The feasibility study involved testing the sealing proposals recommended by PROSE on two different gearboxes of the vehicle. One gearbox was found to have a minor leakage, while the second gearbox showed similar levels of leakage as before, despite the use of a sealing compound and a regular O-seal. These tests helped to evaluate the effectiveness of the various proposed sealing methods and provided valuable data for the further development of the solutions.

Customer benefit

​Based on the results of the tests, PROSE can now make specific recommendations for further steps. PROSE, therefore, recommends that the next step is to test the X-seal and simultaneously apply two lines of sealant to the motor output shaft. This recommendation is based on the observed performance of the tested seal variants and aims to develop a more robust solution to prevent oil leakage. This strategic approach allows the customer to make targeted adjustments and improvements to resolve the problem in the long term and improve the operational reliability and service life of the gearbox.

 

    

Fire Safety Assessment and Consulting

Project tasks

  • Consultancy
  • Development and creation of fire protection concepts
  • Development and creation of evacuation concepts
  • Analyses of fire protection requirements
  • Compilation of required fire protection test reports
  • Communication with authorities, manufacturers and testing laboratories
  • Integration of fire safety systems
  • Preparation of approval documents relevant to fire protection

Our Approach

PROSE analyses the given situation and develops solutions that meet the applicable fire protection requirements. To this end, PROSE advises the customer and identifies various solutions in order to find an efficient way of achieving the required fire protection for railway vehicles in accordance with EN 45545. Our experts calculate the thermal load of the vehicle during the design and propose measures for its reduction.

Customer benefit

The customer benefits from our many years of experience in the field of fire protection for all types of rail vehicles in accordance with EN 45545, including not only advice but also the creation of concepts, the preparation of the necessary fire protection certificates, contact with manufacturers of fire protection-compliant components and communication with approval authorities. The aim is to place fire protection suitable vehicles into service.

Strength analysis (FEA simulation)

Customer: various customers

Project tasks

Development of verification concepts and load assumptions as well as performance of calculations and simulations for:

  • Car bodies according to e.g. EN 12663
  • Bogies and wheelsets according to e.g. EN 13749, EN 13261
  • Streetcars and metros according to VDV 152
  • Attachment parts according to EN 61373
  • General load assumptions from calculations, measurements and simulations for e.g. special vehicles

Static, fatigue and time strength assessment:

  • Base material and weld seams according to FKM Guideline
  • Fatigue of steel according to Eurocode 3 DIN EN 1993-1-9 and BS 7608
  • Weld seam evaluation according to DVS 1612 / DVS 1608 and IIW recommendation
  • Screw connection according to DIN 25202:1-6, VDI 2230 and Eurocode 3 DIN EN 1993-1-8
  • Cylindrical helical spring according to EN 13906

Further analyses:

  • Nonlinear and crash analyses
  • Heat transfer analyses
  • Topological optimizations
  • Eigenvalue analyses
  • Stability analyses
  • Damage analyses and repair solutions

Our Approach

Depending on the customer’s specifications, PROSE carries out strength analyses in parallel with the design in its own development team or works directly with the customer’s team. PROSE covers the entire range of the analysis from the development of the load assumptions to the modelling to the efficient execution of the calculations and simulations as well as the evaluation of the results. Based on the strength analyses, PROSE can prepare test specifications for structural tests, accompany tests and, if required, validate the strength model with the evaluation. PROSE engineers have interdisciplinary know-how also in non-railway specific problems. Furthermore, PROSE also takes over the coaching of simulation processes and supports as a neutral consultant.

Customer benefit

Through the early use of strength analyses in the design process, weak points are identified and eliminated at an early stage, costly test series are avoided and the quality of the product is decisively improved. In addition to a qualified calculation, PROSE attaches great importance to the interpretation and presentation of the results required for the customer, including explanations and, if necessary, documentation relevant for approval. Due to its great flexibility, PROSE can respond to customer requests at very short notice

        

Expert opinion on fire safety for dual-purpose space – air box / shunter’s compartment

Customer: ZAUGG AG EGGIWIL, Switzerland

End customer: Trafikverket, Sweden

Project tasks

  • Standards research
  • Situation assessment from the user’s point of view
  • Preparation of an expert opinion

Our Approach

PROSE’s specialists prepare an expert opinion describing under which conditions the ZRR10000M snow cutter locomotive can be driven in reverse in working mode with the air box occupied. This opinion has been prepared to be submitted to the concerned Swedish authorities. The expert opinion is based on a simple FMEA on the subject of reversing with occupied the air-calming-room. Each case was considered, evaluated and, if necessary, operational or technical measures were defined.

Customer benefit

Since the view of this opinion was shared by the end customer and the licensing authority, ZAUGG has the legal certainty to offer the occupation of the air-calming-room and also knows the conditions for this.

 

Verification of clearance between infrastructure gauge and infrastructure

Customer: Stadtwerke München GmbH (SWM), Germany

Project tasks

  • Support of the SWM project management in the technical evaluation of the results of the infrastructure survey
  • Interpretation of the results with regard to the requirements resulting from §18 of the BOStrab (German regulation on the construction and operation of tramways)
  • Recommendation of the measures to be taken
  • Preparation of the final report of the initial survey for the individual metro lines for submission to the technical supervisory authority

Our Approach

​With laser surveying, the existing installations are recorded with a precision that was previously impossible. PROSE supports the SWM project management in the technical evaluation of the results of the infrastructure survey. This includes the interpretation about the requirements resulting from §18 of the BOStrab as well as the measures to be taken. In addition, PROSE prepares the final report of the initial survey for the individual metro lines for submission to the technical supervisory authority.

Customer benefit

PROSE has experts with many years of expertise regarding the interaction of infrastructure and vehicle and especially regarding the clearance of the light area. This enables PROSE to advise clients on the interpretation of the applicable guidelines in case of ambiguous facts. PROSE was able to prove to SWM that several objects, which were initially classified as violating the clearance, do not pose a threat regarding the clearance. Thus, the customer could avoid a cost-intensive dismantling of these objects.

Running dynamics analysis of rail vehicles (MBS simulation)

Customer: various customers

Project tasks

  • New vehicle developments:
    Feasibility studies, risk analysis (failure conditions) and support of concept studies based on computer simulations
  • Vehicle approval:
    Simulations for the assessment of running characteristics, model validation, simulations for the extension of approvals, simulations related to track access charges
  • Investigation of operational issues:
    Clarification of causes for derailments, assessment of the effects of changes, analysis of unexpected wear, wheel-rail interface studies
  • Special operational conditions:
    Pushing/pulling of inoperable multiple units, propelling tests
  • Wheel set torsional vibrations
  • Special applications such as gauge changing bogies, maglev or (suspended) monorails

Our Approach

PROSE has many years of experience in the dynamic simulation of rail vehicles, acquired through the running dynamic analyses for various own bogie developments and many calculations for manufacturers and operators. PROSE has also supported various innovative developments and research projects. Due to this expertise, PROSE is the suitable partner for the investigation of challenging questions in the field of rail vehicle dynamics. Through analyses and simulations, PROSE helps customers to identify weak points at an early stage, to avoid costly test series and to decisively improve the quality of the products.

PROSE covers the entire range of simulation steps, from the definition of the simulation task, the system boundary conditions and the compilation of the required model parameters to efficient model building, execution of the simulations and evaluation of the results. Based on many years of experience, PROSE is able to reliably estimate parameters which are difficult to determine and to select the appropriate modelling depth for the respective problem. The commercial simulation software system SIMPACK as well as special applications developed in-house are available for the calculations. Depending on customer requirements, PROSE carries out analyses in parallel to the design process in the own development team or as part of the customer’s team. PROSE also contributes with interdisciplinary know-how to non-railway-specific solutions.

Customer benefit

Qualified simulations reduce the development risk or help to solve problems that have occurred. In addition to a qualified calculation, PROSE attaches great importance to the interpretation and presentation of the results to the customer, including in-depth explanations and the necessary formal documentation relevant to homologation if requested. PROSE can also provide coaching support for simulation processes and act as a  neutral consultant. Due to a flexible organisation, PROSE can respond to customer requests at very short notice.

         

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