Senior Mechanical Engineer at CAMRAIL

The problem

Optimising and reconfiguring the mechanical and pneumatic systems of ageing intercity locomotives — BB1100, CC2200, CC3300 and CC3300-AC — amid rolling-stock and spare-part shortages. While preparing locomotives for operational validation, we uncovered incompatibilities in the compressor test bench, a crucial tool for preventive and corrective maintenance. The compressor ensures air compression and oil circulation for braking, control and auxiliary systems, yet the existing bench could only test BB1100 and CC2200 units — other models needed fragmented testing across separate locations, costing time, traceability and reliability.

The approach

I defined and implemented a new testing methodology to turn the bench into a versatile, modular, universal system able to run pressurised-air, water and oil tests across compressor types. Three parallel workstreams: a full 3D model of the bench (frame, mounting interfaces, testing zones) accommodating units from compact BB1100 to larger CC3300; a low-cost modular frame built for multi-compressor compatibility, easy assembly and enough rigidity to limit test vibration; and a functional analysis of vibration, air/fluid-jet forces and compressor–structure interactions to prevent instability or failure during testing.

Additional scope

Beyond the bench, I tackled recurrent radiator overheating — driven by ageing components, unavailable original parts and locally-made alternatives disrupting airflow. I analysed ventilation impacts, proposed pneumatic-system modifications, integrated additional radiator ventilation, and ensured the changes didn't interfere with other mechanical or pneumatic systems.

The problem

A technical contributor on the brake-support design and adaptation for BB1100 and CC3300 locomotives, where original components were no longer available. In these pneumatic systems, compressed air at 3.8 bar actuates cylinders that press brake shoes against the wheel. I found three fundamental failure modes in the existing support: excessive mechanical play from worn axles and pivots, fatigue of suspension springs, and corrosion weakening structural integrity — manifesting as longer stopping distances and the risk of catastrophic failure under load.

The approach

Rather than jump to conclusions, I started with one question — what are we actually observing? Dimensional measurements confirmed pivot play exceeding spec by 300%. I gathered insight from engineers who knew these systems intimately and built a fault tree around the most probable mechanisms. Then, using SOLIDWORKS for 3D modelling and ANSYS for FEA, I designed an optimised support: S235JR structural steel for yield strength, weldability and fatigue resistance; gusset reinforcements at critical load paths to eliminate weld-joint stress concentrations; and a manufacturing route of precision cutting, fixture-assisted alignment, qualified MIG welding, post-weld grinding and protective coating.

The result

Structural analysis validated the design with adequate safety margins and a predicted service life beyond typical overhaul intervals. Assembly followed a systematic protocol — pressure testing, static load testing to 150% of design braking force, and dynamic testing under simulated braking cycles. The outcome: fewer maintenance interventions, tighter mechanical tolerances and better braking response, longer component life, and higher structural safety factors. The real lesson was the method — observe carefully, analyse systematically, validate thoroughly, and always respect the expertise of those who work the equipment every day.