I thought some people would find a map of Thivim and Margao Train Stations useful. I managed to create a layout of each a couple of days ago and thought they might come in handy.
Margao Train Station Map and Taxi Prices (Govt Rates)
http://www.poipleshadow.com/Goa-Margao-Railway-Taxi-Price-List
Thivim Train Station Map and Taxi Prices (Govt Rates)
http://www.poipleshadow.com/Goa-Thivim-Railway-Taxi-Price-List
Do let me know if they are helpful!

Thanks