Official site is showing extension up to SMI but not for return train.
13156 MITHILANCHAL EX 06-07-2012 SITAMARHI KOLKATA GENERAL
S.No. Date (DD-MM-YYYY) Class - SL Class -3A
1 6- 7-2012 RAC40/RAC 32 WL 7/WL 2
2 9- 7-2012 AVAILABLE 187 AVAILABLE 2
3 13-...
more... 7-2012 AVAILABLE 317 AVAILABLE 22
4 16- 7-2012 AVAILABLE 353 AVAILABLE 33
5 20- 7-2012 AVAILABLE 373 AVAILABLE 40
6 23- 7-2012 AVAILABLE 381 AVAILABLE 33