MEA is a state defined lower limit of an airway or route. It has to meet obstacle clearance, but it can be well above obstacles.
MOCA and MORAs are obstacle related and they can be (vertically) out of the airway, till the point where the minimum obstacle clearance is met.
So, you can have an airway with a MEA of FL 140 with a MORA of 3,000 ft, for instance