A journey through Hajj, Islam's special pilgrimage
http://edition.cnn.com/2017/08/30/middleeast/hajj-journey-by-the-numbers-2017/index.html
Mecca Metro has been constructed to transport pilgrims. And, one section has already been inaugurated.
But, even if public transportation between Hajj points is well prepared, it's not possible to prevent accidents at each point unless an authority restrict entry.