For harnesses in vehicles, rolling stock and machinery, crimping is the standard method, and soldering is avoided wherever the harness vibrates.
The reason is solder wicking. Molten solder runs up the strands under the insulation and turns a flexible conductor into a stiff rod. Under vibration, bending concentrates where the solder stops, and the strands fatigue and break there, often hidden under intact insulation. A correct crimp compresses only the stripped conductor inside the terminal barrel, so the strands behind it stay flexible, while the insulation grip carries bending loads.
Crimps also suit controlled production. Crimp height, pull-off force and cross-sections can be measured, as described in the harness testing guide. On Indian Railways work, crimping sockets are specified to EDTS-200, EDTS-201 and ICF drawings. See APAR locomotive harnesses and automotive and EV harnesses.