（解説文要約）
炭車が脱線した際、後続する車の追突をさけるため、後山はカンテラを振り、「オオライ」と叫びます。
この「オオライ」は坑内では「トマレ」の意味です。
坑外と逆の意味ですが、その語源はよく分っていません。
When derailments occurred in coal drives,
the female carrier known as Atoyama waved her lantern and called out "O-rai" to stop the following cars from crashing in.
Although"O-rai" originally meant "All engines go", it had exactly the opposite meaning in coal mines: STOP!
No one knows the reason why this term was used.