It should have been made regular... Vaishali had 3 pairs of wdp but now they are not in use... 15050/49/51/52 are not getting e2e eloco and reversal is also done at bju hence giving a wdp out for these trains will solve the issue... From cpr 15050 has avg speed comparable to 12554 as well as of 15052 from mfp hence it will do justice as well :)