Hello Vikas,

Technically speaking the rank of various colleges is available in net,  but what cllg will be best for you depends on various factors.... 
1-location is an important factor... 

• Language difference in south indian colleges for north indian student and vice versa,,,,,  although this factor can be managed.
• Distance from home. Well you do remember your home every now and then,  so it's better if your college is not that far from your home.
• College near to any industrial area is preferred for more exposure, etc

2-Mechanical as a branch doesn't contain that much of female students, so you better be ready for that. 
3- About placements,  most of the PSU'S are now hiring on the basis of GATE,  so campus placements are less than previous years,,  but top four NIT's still have good campus placements. 

Rankwise I saw it in some website,  there was no mention of Warangal in it 

1. Tirchi mechanical
2. Suratkal mechanical
3. Allahabad mechanical