In between SC and YPR, this train is literally a walk in train. When you book it on say a Wednesday evening, you would get a W/L in almost all the classes. However, come Thursday noon, all of the W/L would disappear, and vacancies would be available under current booking. I traveled on 14th October,and my observations are from this trip.
You could buy a general M/exp ticket from SC to any of the commercial halts that this train has, towards YPR, and you can get a berth on the train in a class of your choice(2A/3A/SL). Even the general compartments are reasonably empty.