AC Class is bad for railfanning. I prefer SL. Ideal railfanning scope for me could be:
SLB with myself facing towards the loco and SLB is placed at the traffic side, in a SF/Duronto Express run on time by WDP4B/4D/WAP7, which will never be overtaken, rather will overtake other trains including SF ones too, having a runtime of both day and night, on days of pleasant weather.