Senior Mechanical
Engineer at CAMRAIL

The Problem

At CAMRAIL, I worked on the optimisation and reconfiguration of mechanical and pneumatic systems on intercity locomotives, focusing on aging models such as the BB1100, CC2200, CC3300, and CC3300 AC, within the context of rolling stock and spare parts shortages. During one critical phase, while preparing locomotives for operational validation, we uncovered subtle incompatibilities in the locomotive compressor test bench — a crucial tool for preventive and corrective maintenance.

The locomotive compressor ensures air compression and oil circulation, essential for pneumatic systems like braking, control, and auxiliary operations. The existing bench was limited to testing only BB1100 and CC2200 compressors. Other models required fragmented testing in separate locations — water tests in the wash area, hydraulic tests in the garage — introducing time loss, traceability issues, and higher risk of errors.

The Approach

My role was to define and implement a new testing methodology to transform the bench into a versatile, modular, and universal system capable of performing pressurised air, water, and oil tests across multiple compressor types. This involved three parallel workstreams:

• 3D Modelling and Design — I completed a full 3D model of the bench including the main frame, mounting interfaces, and functional testing zones. The design accommodated compressors of widely varying sizes and weights, from compact BB1100 units to larger CC3300 compressors.
• Low-Cost Modular Frame — The frame was designed for compatibility with multiple compressors, ease of assembly and disassembly, reduced manufacturing costs, and sufficient mechanical rigidity to limit vibrations during testing.
• Functional Analysis and Dynamic Constraints — I analysed vibration characteristics, forces from air and fluid jets, and potential interactions between compressors and the bench structure to prevent instability or mechanical failure during testing.

Additional Scope

Beyond the test bench, I also addressed recurrent radiator overheating in locomotives. This issue arose due to aging fleet components, unavailability of original parts, and the integration of locally designed alternatives that disrupted airflow. My responsibilities included analysing ventilation impacts, proposing pneumatic system modifications, integrating additional radiator ventilation devices, and ensuring the changes did not interfere with other mechanical or pneumatic systems.

The Problem

I served as a technical contributor on the brake support design and adaptation project for BB1100 and CC3300 locomotives, where original components were no longer available due to supply chain constraints and obsolescence. The task required us to build the metaphorical fighter jet while flying it.

In these pneumatic braking systems, compressed air at 3.8 bars actuates brake cylinders that apply force through a lever mechanism to brake shoes pressing against the wheel's rolling surface. During my investigation, I found three fundamental failure modes in the existing support: excessive mechanical play from worn axles and pivots reducing braking precision, fatigue of suspension springs leading to loss of rigidity, and corrosion weakening structural integrity. These manifested as longer stopping distances, increased risk of mechanical failure, and potentially catastrophic component breakdowns under load.

The Approach

Our experienced workshop engineers jumped to conclusions — rightfully so, given their years maintaining these locomotives. I called the room to order, grabbed a cardboard box, and started with a single question: what are we actually observing? My dimensional measurements confirmed play in the pivot connections exceeded specification limits by 300%. I pushed through "low-gear problem-solving," gathering insights from engineers who knew these systems intimately, and built a fault tree that circled the most probable failure mechanisms.

After splitting analysis between team members, I used SOLIDWORKS for 3D modelling and ANSYS for finite element analysis to design an optimised brake support addressing all identified failure modes. Key decisions included:

• Material selection — S235JR structural steel for adequate yield strength, good weldability, fatigue resistance under cyclic loading, and cost-effectiveness for rail applications.
• Geometry optimisation — Gusset reinforcements at critical load paths to stiffen the structure, distribute loads evenly, eliminate stress concentrations at weld joints, and provide adequate maintenance access clearance.
• Manufacturing process — Precision cutting, fixture-assisted alignment for consistent weld geometry, qualified MIG welding procedures, post-weld grinding, and protective coating for corrosion resistance.

The Result

Comprehensive structural analysis validated the design with adequate safety margins and predicted service life exceeding typical locomotive overhaul intervals. The assembly followed a systematic protocol with pressure testing, static load testing to 150% of design braking force, and dynamic testing under simulated braking cycles. We achieved significant reduction in maintenance frequency, improved braking response with tighter mechanical tolerances, extended component life through superior corrosion resistance, and enhanced safety with higher structural safety factors.

The key to success was not just the technical tools, but the disciplined problem-solving methodology: observe carefully, analyse systematically, validate thoroughly, and always respect the expertise of those who work with the equipment every day.