I travelled in Pune Chennai Garib Rath Winter Special Express last month(Oct 2012). Here are the details: It is always late at least by 3 hours upto Wadi Junction. Beyond Wadi, it has a buffer time and runs very fast in that zone upto Pune. It is always late by at least 1.5 Hours every time.
In Return Journey, the train suppose to leave Pune around 14.15 Hrs but usually leaves at least 1 hour late and reaches Chennai at least 3 hour late.
There is no Pantry car and No catering...
more... service available. So when train stops at Renigunta from Chennai you can coffe, tea and dinner. Your next Morning Tea/coffe will be at Gulbarga, Breakfast at Solapur and final mid-morning snacks at Daund. I have noticed tea/coffe/water vendors between Gulbarga and Daund. Please remember to buy water bottle before boarding this train from Chennai Or else you will be thirsty until the next station.
In Return Journey from Pune to Chennai, dinner is at Solapur. Morning tea/coffe is at cuddapah. But the worst part is wait until Renigunta for breakfast which could be beyond 10 AM since it would be running late.