Delta Flight 30 from JFK to SVO -- Aug 30. Flight pushes back, taxies for 2 hours, returns to gate because of mechanical problem, mechanical problem fixed, pushes back, taxies for another two hours, returns to gate with another mechanical problem. Everybody told to get off plane and take all belongings. Flight scheduled for 4.5 hours hence (am waiting for flight now). Flight is basically scheduled to depart 8.5 hours after original schedule. 4 hours spent on tarmac with a break at the gate in the middle; 4.5 hours (and counting) in terminal. Everybody in same boat. cause is equipment failure and failure to have spare plane at JFK. Am not experienced in cases like this. Am curious if Delta owes any compensation here.