OEM vs Aftermarket
What the distinction means, and what to verify before you order.
OEM vs. Aftermarket EMD Engine Parts
"OEM" (Original Equipment Manufacturer) parts are made by, or under license from, the company that built the original engine. "Aftermarket" parts are made by an independent manufacturer to the same fit, form, and function — without a license from the original engine builder.
Neither category is automatically better; the real question for a locomotive, marine, or power-generation operator is whether a specific part meets the tolerances, material standards, and compatibility your engine requires — and whether the manufacturer can prove it.
Apex International manufactures OEM-grade, EMD 645 & 710 compatible replacement parts under an ISO 9001:2015 certified quality management system (certificate no. KSRQA2411188919). We are an independent manufacturer, not EMD or Progress Rail — our parts are built to match OEM fit, form, and function, and every part page lists its EMD part number and DLW cross-reference number where applicable.
What to Verify Before You Order
Is the part manufactured to OEM specifications?
Ask for the dimensional tolerances, material grade, and compatibility data for the exact EMD engine model and part number — not just a generic "fits most engines" claim.
Is the manufacturer independently certified?
A recognized quality management certification (such as ISO 9001) means the supplier's processes are audited by a third party, not just self-declared.
Can the supplier trace the part back to its production batch?
Traceability lets you confirm material source and manufacturing date if a warranty or quality question ever comes up.
Does the part number match a documented cross-reference?
For EMD parts this usually means matching both the EMD part number and, where applicable, the DLW (Diesel Locomotive Works) cross-reference number.
How Apex International Addresses These Questions
Certified quality system
Manufactured under an ISO 9001:2015 certified quality management system.
Documented part numbers
Every part is listed with its EMD part number and, where applicable, its DLW cross-reference number.
Independent manufacturer
We manufacture and export OEM-grade compatible parts; we are not affiliated with EMD or Progress Rail.