There is a luggage policy, but luggage is usually not weighted at check-in unless you carry a refrigerator, plasma TV, or a huge bag that exceeds the dimensions of 1m x 1m x 0.7m.
The luggage allowance varies for different classes of travel:
First class:70kg;
AC 2-Tier sleeper: 50kg;
AC 3-tier sleeper/AC chair car/Sleeper class: 40kg;