What is the difference between traditional tragedy and a modern-realistic tragedy?Give examples.

I would say the one of the primary differences between the tragedy of the moderns and that of the ancients is its "democratization."  Essentially, this means that anyone can suffer and feel immense pain due to their own tragic condition.  In the time of the ancients, tragedy was confined to the realm of the regal and the royal.   We see kings and queens, princes and princesses, as being the sole recipient of tragic conditions and the hurt inherent in tragedy.  Oedipus, Creon, King Lear, Macbeth, Hector, or Achilles all contain similar royal lineage and representations as well as being the recipients of tragedy.  The modern sense of tragedy involves real people that are outside the realm of the noble and the regal.  Blanche DuBois, Willy Loman, John Proctor, Faust, or Emma Bovary are those who suffer in tragedy and are not kings or queens. They are regular people, common people.  In this democratization of tragedy, the experience hits closer to our own identities as there are more "regular people" than kings and queens in the world.