which is the fastest train in terms of average speed in various categories. all categories of trains SF, mail, ICE, raj, duronto, shatabdi etc can be included
o)end to end travel under 250 km
a) end to end travel under 500 km
b) end to end travel under 1000 km
c)...
more... end to end travel under 1500 km
d)end to end travel under 2000 km
e) end to end travel under 2500 km
f) end to end travel under 3000 km
thank you in advance for your responses