I was quite amazed when I found the chennai Metropolitan Transport Corporations bus website with lots of useful information. This will be of great help for those looking for Bus Routes, connections, AC Bus timings, frequencies and various stagewise bus information of Chennai's Local Bus service ie MTC.
In the stagewise route information you can select any starting (or boarding ) point and Destination and the site gives all the Buses covering the routes (even if your boarding point is in middle of a route). Also the expected time of journey, frequencies and map (under construction as of now).
Route List of All Chennai MTC buses : All Chennai MTC Routes
Time table Time List of All Chennai MTC buses : All Chennai MTC Bus Timings
Route List of All Chennai MTC buses : All Chennai MTC Bus Stops / Locations
Stage Bus Stop List and Routes MTC : https://www.dexternights.com/mtc-route/all-stages
AC Bus Timings : AC Bus Timings