Hi Roj Rav,
This tickets with WL 26,27,28 seems quite difficult to get confirm.
If you can manage to make your journey after 3 days then I would suggest to please go with #Special train 09311/Indore Kolkata weekly Express.
Below are availability status I checked, and both will get confirm sure shot :
15-11-2015:...
more...
GNWL50/RAC11 (3AC)
GNWL163/WL57 (Sleeper class)
Available 450 (2S Second class sitting on chair)
.
The past few days punctuality was also good. It may get delay by 1-2 hours and reaches Gaya in the afternoon.
.
Pleasure to help. Thanks:)