TMX Solutions upgrades drive unit test stand at Alstom in Netphen
Integrating external drive technology with a variable frequency drive and automation for motorless drive units
Starting point: new requirements
At its Netphen site, Alstom runs a service center for the maintenance, repair, and overhaul of bogies. A key part of the service process is an enclosed drive unit test stand. Overhauled drive units go through a final functional and quality test on it.
Until now, the test stand was designed for drive units with an integrated motor, including those of the TRAXX platform. These units bring their own traction motor and run directly on the test stand.
As Alstom expanded its service activities in Netphen, including the overhaul of Talent drive units (Alstom) and Vectron drive units (Siemens Mobility), the existing test stand had to be adapted. The goal: use the test stand more flexibly, take on additional test orders, and avoid building a separate new one.
The technical challenge
Every drive unit consists of a motor, gearbox, shaft, and wheelset. TRAXX units arrive at the test stand with their integrated motor. Talent and Vectron units are different: they arrive in Netphen for overhaul without a motor.
For the test stand, this means an external auxiliary motor must drive the gearbox input shaft. The motor must be sized to overcome the friction torque of the drive unit reliably and to accelerate the rotating masses safely, without being oversized.
Further requirements:
- Dissipate the energy fed back during braking safely
- Serve two different test fixtures (one for Talent, one for Vectron) flexibly
- Integrate the new technology seamlessly into the existing test stand, including the safety circuit and user interface
The solution: integrate, don't replace
TMX Solutions developed a targeted upgrade of the existing test stand. At its core is an additional control cabinet with a variable frequency drive and an external braking resistor. It powers the auxiliary motors on both test fixtures.
A single drive serves both motors alternately. When the operator switches between test positions, the parameter sets change automatically. The operator selects the test; the system configures itself in the background.
Main components of the upgrade:
- Control cabinet with variable frequency drive for the auxiliary motors
- Dedicated PLC for sequence control of the drive functions
- Connection to the existing measurement and automation system
- Dedicated user interface, integrated into the existing operating structure
- Dual-channel integration into the existing emergency stop circuit, including the door interlock
- Automatic switching of parameter sets for each test fixture
- Fully automated test sequences, including test reports
The existing test stand architecture stayed largely unchanged. Changes to automation and operation were kept to the minimum needed.
Implementation: three months from engineering to commissioning
TMX Solutions handled the engineering, the integration into the existing automation, and commissioning. Complete test sequences ran on both test fixtures to make sure all functions work together correctly, from parameterization to the test report.
The upgrade was carried out between December 2025 and February 2026, without significant impact on ongoing service operations.
Result: different platforms, one test stand
With the upgrade, Alstom can now test drive units from different vehicle platforms on one test stand in Netphen, including external orders such as Siemens Vectron units. Utilization of the existing test stand rose significantly, and no additional test stand had to be built.
Around 1,100 drive units a year are now tested on the upgraded test stand. The system has evolved from a platform-specific test stand into a flexible service platform.
From the field
The upgrade by TMX Solutions lets us use our existing test stand much more flexibly and opens up new testing options. We were especially convinced by the practical implementation and the close, solution-oriented collaboration.
-- Sven Wohlfeld, Project Manager Service Test Stands, Alstom in Netphen
Download the report
Read the full reference report on the Alstom project, with all details and photos, as a PDF (in German):
More information
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