TS Rail Disasters Spinoff: High Speed Mysteries (2013 Morioka & Providence train accidents)

A two-parter spinoff episode covering two unsolved high-speed accidents that occcured at the same time in the U.S & Japan.

Epsiode 5: High-Speed Mysteries
Part 1: Morioka, Japan
On April 29, 2013, a morning Tohuku Shinkansen train bound for Tokyo suddenly jumps off the rails and crashes into a passing commuter train traveling the same direction. 63 people are killed, and an a entire nation is brought to its knees. How would one of the safets high-speed systems in the world have a serious accident?

Part 2: Providence, RI
On the same day in the evening, an Amtrak Acela express collides with a stopped MBTA commuter train shortly after leaving Providence killing 12. It it's Amtrak's first serious accident involving its flagship high-speed train.

Since these crashes happened at the same time so sudden, it has compelted investitgators from both countires. Feel free to share your thoughts on what could of possibly went wrong.