When procuring OEM trains, you must prioritize structural integrity and propulsion systems. Key specs include the track gauge compatibility (e.g., Standard 1435mm or custom), body material (typically high-grade aluminum alloy or stainless steel for corrosion resistance), and power source (Electric, Diesel-Electric, or Battery-powered). Ensure the braking system meets international safety standards like UIC or AAR, and verify the maximum axle load to ensure compatibility with the target infrastructure.