The M-stock (or "CM-stock") of M-Train are the oldest trains on the MTR, built originally by Metro-Cammell (now Alstom) and refurbished by United Goninan.
Rangkaian M-Stock (atau CM-Stock") dari M-Train adalah kereta tertua di MTR, aslinya dibuat oleh Metro Cammell (sekarang Alstom) dan di diperbarui oleh United Goninan.