One of the major reason behind this is HWH being the HQ of SER. Why having both ER's as well as SER's HQ in HWH!! Instead of whole SER, only HWH gets the required attention. SER HQ should be shifted to Either RNC or TATA for better administration.
Actually in 1988, 8013/8014 number was allotted to it which later changed to 8113/8114 and then to 2813/2814. It can be verified by irfca database. The reason might be earlier this train would have been owned by kharagpur division with code 80xx and then transferred to chakradharpur division with code 81xx and then to super fast of SER with code 28xx