Triceratops vs. Edmontosaurus

The triceratops was a massive monster with three sharp horns on its face. The Edmontosaurus was even larger, and with its speed and thick skin, it couldn't be pushed around easily. Neither the triceratops nor the Edmontosaurus ate meat. But in the fight to survive on scarce resources, these herbivores may have been compelled to fight. Who would win?