> that operation took years of planning. Near the end of the 3.5 hour track change video, it says it was the culmination of 80,000 people working for 8 years.

> that operation took years of planning. Near the end of the 3.5 hour track change video, it says it was the culmination of 80,000 people working for 8 years. ８年間８万人の集大成