Obsolescence management in public transport – securing spare parts, maintaining stable operations

In the ongoing operation of rail vehicles and infrastructure facilities for public transport, breakdowns due to spare parts no longer being available pose a high risk. Many manufacturers discontinue the production of components after a few years—especially in the case of older traction vehicles or control systems.

In the public transport association in North Rhine-Westphalia under consideration, several safety-related and mechanical assemblies faced this problem: parts had been officially discontinued, suppliers were no longer available, or minimum order quantities were economically unviable. The goal was to create a sustainable and cost-efficient solution to maintain operational readiness—without interfering with the approval of the vehicles.

Zilken took over obsolescence management as a strategic and operational partner of technical purchasing:

• Identification of critical components in existing plants and vehicles (fault and life cycle analysis).
• High-quality manufacturer search and supplier research via the existing international Zilken network—with a focus on functionally compatible replacement and successor parts.
• Technical verification and sample approval in collaboration with the customer's specialist departments (workshops, maintenance, quality assurance).
• Auditing and qualification of new suppliers, including documentation and transfer to the material master data.
• Long-term delivery and price security through framework agreements, alternative manufacturers, and stockpiling concepts.

Through the structured comparison of technical specifications, material numbers, and manufacturer archives, several discontinued components could be replaced with identical or functionally compatible spare parts. Zilken coordinated supplier qualification and took over strategic purchasing from the new sources of supply.

This resulted in a stable MRO process: critical parts were replaced, inventories were built up in a predictable manner, risks were documented, and costs were stabilized in the long term. Operations could continue without expensive reengineering measures or custom-made parts—with consistent proof of technical suitability.