Anga exp train no is 12253
Here the train no series is 122xx series
122xx series for train no is used by almost all zones especially by Duronto and Garibrath
Some other trains with 122xx train no series
12201...
more... LTT KCVL Garibrath ( SR train )
12203 ASR SHC Garibrath ( NR train )
12213 YPR DEE Duronto ( SWR train )
12220 SC LTT Duronto ( SCR train )
12289 CSMT NGP Duronto ( CR train )
12273 HWH NDLS Duronto ( ER train )
12245 HWH YPR Duronto ( SER train )
12237 BSB JAT Begampura SF express ( NR train )
IMO the reason why anga exp has train no in 122xx series is because SR and SWR zones share a common zone no 6 i.e, Train no of SR and SWR zones share with 126xx, 16xxx, 226xx, 206xx series
126xx is used by almost all the SF trains of SR and SWR , mostly SR and no train no in 126xx is vacant so some trains have used 122xx series
160xx series - MAS division
161xx series - MAS division but used by trains starting from MS and TBM
162xx series - MYS division
163xx series - TVC division
165xx series - SBC division
166xx series - Shared by PGT and SA division
167xx series - MDU division
168xx series - TPJ division
169xx series - currently not used but the passenger train version i.e, 569xx is used by UBL division