You are confused i think.
Both Shaheed & Sarayu Yamuna are more than 25yer old trains.
Shaheed was SF originally with PC (not so sure) and intended to ease burden of Vaishali the only SF on NER then.
Saryuyamuna was introduced to serve East UP part of NER thats why it has ZigZag route and both train were running between MFP-DLI with Flying Mail...
more... RSA .
Shaheed lost her SF tag with many train including Vaishali (then pride of NER). Interestingly Vaishali regained SF status due then NER GM D Hariram's strong lobbing at RB.