Regarding Food If you are travelling from Mumbai/Pune to Odisha:
1st Night, you can either pack your food from Pune by online portals like Travelkhana.com or comesum.com or travelerfood.com or Railrider.in. Or else you can even try the Train's Pantry food which is made in the pantry itself and is of Better standards.
2nd Day Breakfast, do it at Secunderabad. Trust me, Hot idli-vada-sambhar are served which are pretty awesome. Also don't forget to try those small samosas (Rs 10 for 5) available at Kazipet station or even try those Big hot samosas...
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(Rs 20 for 2) of Pantry Car. But do check the price before buying.
2nd Day Lunch should be done at Vijaywada , if you don't want Pantry food. Veg-Non Veg Biryani and Thali are available at Platforms. Or else you can even try comesum food parcel.
2nd Day evening tym , Pantry people sell tasty noodles and Samosas (I loved those samosas because even though its bit pricey, but they were really big and spicy with real Aloo stuffings).
2nd Day Dinner, None Other than Visakhapatnam. Konark express is always placed on platform 1 and Good food is available on Platform No 1.
Tea and Coffee is sold through out the journey but Availability of Soup is bit doubful.
PS: You can ask for Any type of Thalis from the Pantry. Be it Ala Carte thaali or full fledge thaali or just seasonal Thaali. Ask the pantry boy for Rs 50 wala Thaali. He gonna do all kinds of tricks for not to bring you that thaali with even telling you the cost to be more or food quantity/quality to be less. Don't pay heed to them.