Travelled on the same day on same train but towards Mumbai side.Here are my observations
-Good run between Pune to Lonavala and Karjat to Kalyan.
-If luck isnt on your side,it will halt at kalyan as Geetanjali express also comes at the same time and if 12128 reaches late kyn,Geetu will go ahead.(Beneficial for kyn commuters though)
-Snacks are available