Negative List Section 66Da(p) transportation of goods by road is exempt except the Service of GTA and Courier agency .
Your case is also exempt in the mega exemption notification 25/2012 , So no service tax in your case.
Also Refer the recent Circular of CBEC regarding Delivery of Milk by train Service Tax on services by way of transportation of goods by Rail/Vessel - Transportation of milk - CIRCULAR NO.167/2 /2013 - ST [F.NO.B-1/2/2010 -TRU], DATED 01-01-2013.