The Texas Mexican Railway is a KCS subsidiary that connects it to the (also a KCS subsidiary) KCSM in Mexico. The KCS has been in the process of completely absorbing it, leaving only a single unit (GP38-2 #858) lettered for the Texas Mexican.
The TM’s paint shop, in a small act of rebellion, has painted the TM’s Lone Star logo under the cab window in place of the lettered reporting marks that were painted there when 858 was first replanted into KCS gray.