Beggars on trains

Ronie : Dad, why beggars are allowed to travel free on our trains ?

Dad : Because they clean II class coaches free of charge.

Ronie : But why aren't they allowed in AC classes ?

Dad : Here they become suspicious. No more question son.

Ronie : One more question Dad, "Who runs our train" ?

Dad : God.

Ronie : If it is so, then why Driver is paid ?

Dad : He keeps an eye on God who runs the train, no more question.