Brake Beam Fatigue Test Cycle Machine
Objective: Build a full-scale machine that runs railroad brake beams through up to 1,000,000 load cycles under real-world braking forces.
Client: Cardwell Westinghouse (a Wabtec company)
Role: Mechanical Design Engineer
Scope: Machine design, FEA, production drawings with GD&T, fabrication and assembly support, testing
Tools: SolidWorks, SolidWorks Simulation, servo-hydraulic actuation
Overview: Brake beams must survive millions of braking events over a railcar's life. To prove new designs before they go into service, Cardwell Westinghouse needed a machine that applies the same braking forces again and again, precisely, without drifting out of alignment.
The project covered the complete mechanical design, FEA validation, and hands-on fabrication coordination of a rigid, modular fatigue test system built to run millions of high-load cycles without structural wear or misalignment.
Brake Beam Test Cycle Machine
Machine Design
A multi-bay steel base frame supports two opposing reaction stations, each with high-strength machined fixtures that locate the brake beam under test. The structure is fabricated from A36 and A572 structural steel with Grade 8 bolting, so it can be taken apart and reconfigured.
Dual reaction arms with high-load hydraulic actuators that reproduce real braking forces
Linear guides that keep the moving fixtures aligned under high load
Precision-machined clamp blocks and V-seats that hold the beam pivots in the same position for the full test
Servo-controlled hydraulic cylinder with adjustable stroke and frequency
Interchangeable fixture plates for testing different brake beam designs
CAD & FEA Validation
The machine was fully modeled in SolidWorks, from concept sketches to detailed assemblies: more than 300 machined and fabricated parts, each tolerance-checked for fit and manufacturability. FEA in SolidWorks Simulation focused on the base frame, actuator mounts, and reaction brackets:
Static stress mapping at maximum cyclic load
Modal analysis to keep natural frequencies away from the test frequency
Fatigue life of bolted joints and weldments using endurance-limit calculations
Deflection held below 0.005 in at peak load
The results added gusset reinforcement, improved load paths through the base rails, and stiffened the fixture interfaces to minimize deformation along the machine.
Fabrication & Assembly
The 3D models were released as 2D production drawings with full GD&T. Working on the shop floor alongside the machinists, critical fits were verified as parts were made: actuator pins and bearings, slide-rail alignment, and flatness and parallelism across bolted joints. Their feedback produced real-time design improvements, and the machine's geometry was confirmed during initial assembly and alignment, before the hydraulics were connected.
Testing
After dry runs, the hydraulic system was tuned for repeatable sinusoidal loading at controlled frequencies to simulate brake applications. The machine ran continuously through 1,000,000 fatigue cycles while holding alignment and accurate load profiles, confirming the FEA predictions and the design approach.
Results
Met the 1,000,000-cycle design goal with stable alignment throughout
Became a core R&D testing asset for validating new brake beam designs and materials
Modular, overbuilt construction for long service life and future test setups