IPC/WHMA-A-620C-R rail transit addendum provides additional requirements to IPC/WHMA-A-620C standard, describing materials, methods, tests, and acceptance criteria for producing crimped, mechanically secured, and soldered interconnections. It also provides the related assembly activities associated with cable and harness assemblies in rail transit industry, to ensure the high reliability and environmental adaptability of cable and wire harness assemblies in the high-speed railway environments.