Each Teststand consists of a U-shaped metal base, with build in track-to-track insulation that has perfect power pickup and transfers the power to the engine via 4 high-quality ball bearing wheels. It is important to understand that for testing the engines you need a smooth resistance free operation. Ball bearings are available in a wide variety of quality standards. TRAINLI only uses high end ball bearings that sustain the weight of even the heaviest G-scale engines.
Don't be fooled by cheaper products that don't last or don't do a good job reducing the resistance of the operation.