In SECR, some locos of other sheds are always seen. I mean particular road number of loco. Example TKD P7, ET P4, etc. These particular road numbers are very frequently spotted with trains of SECR. For example, CGSK will be hauling a TKD P7 loco of road number 3034X 95% of times. So we call these locos are of BSP/BIA base. This particular P4 is regularly hauling Chhattisgarh Express.