Ravi Panjwani

In third ac the total no. of births are 64 that means there are 8 x 8 berths per coach, they are more or like sleeper coaches only not that comfortable a little more comfortable are these 2nd ac where there are 6 berths each and in 1st a/c there are only 3 births 

Subha

Ist AC class has four berths in one cabin which you can lock and sleep. In first AC compartment maximum no. of passengers will be 28.there are coupe also which have only two births.
In second AC one section has 4 berths and op post side two births known as side berths.there are curtains provided which you can draw whenever you want to sleep.]
In third AC there are 6 berths and two side berths with no curtains and unlike second AC no reading lights. Also the temp is little high in 3rd ac as compared to 1st n second.. 

ash m

the size of the berth increases from theird to first and the number of copassengers reduces in the same order, in first AC you get a room which has 2 passengers and can be locked. 3rd ac has 8 passengers per section. 2nd ac has 4 passengers.
AM 

Yogiraj Ramanandtirth

1st AC is the top in class with everything in the compartment like dressing room, wash basin and you get the best of everything.
2nd AC is in two forms: 2 tier  Two berths on one side and 3 tier  Three berths on one side.
There is no 3rd Ac now. 

Sajna

They get better the more you pay 

khanapur

The AC coach 3 has 3 tier berths where in 2 AC it has two tier berths. The AC 2 tier coach has curtains for privacy for each compartment whereas in AC 3, there are no curtains. Both in 3 AC and 2 AC there are side berths also..
AC first has two tier berths more wider and have a door independentlly for four berths to have more privacy and compactness. The distance between berths is also more. There are no side berths in AC one coach
The fare is therefore is different as for the extra facilities though all are all airconditioned. 

Mano

All the above four persons has given appropriate & factual answers. 

 
