Power source: overhead contact system, internal combustion engine, power battery, hydrogen fuel cell
Axle arrangement: four-axle, six-axle, eight-axle, twelve-axle
Axle load: 12.5 t–30 t
Environment: all-weather operation under high temperature, extreme cold, and strong wind and sand conditions
Track: different gauges, different voltage systems, different clearances
Transport demand: passenger and freight transport
Simplification and standardization: achieved interoperability among different locomotive models.
