Three passes not mean that only 3 times travelling. It means 6 time travelling in which 3 times UP and 3 times Down with reservation but unlimited travelling with out reservation.
But there is a condition that you cannot travel free after you use your pass for for reservation.
After reservation your pass is cancelled. But before reservation u can travel unlimited.
That's...
more... why most of the time our pass expire without using it in reservation.
Also there are 3 PTO in a year which will provide the facilities of 1/3 fare of general class in sleeper class. But 1/3 of AC in AC class .
that's why people who travel more use PTO for their reservation in sleeper . For eg if you want to travel NDLS to BCT and the fare of GENERAL Sleeper is as 300 and 600 than you hv tp to pay only 100 in sleeper class.
so bro pass is unlimited before reservation . TTE ko pahle apni job bachani h na ki 13 lakh employees and unki family ko without permission allow karna h.