Original: 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.
Simplified: 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.