出典:Wiktionary
The railway sense is derived from the 1960s TV series Thunderbirds, about a secretive high-tech rescue organization, ultimately from thunderbird.
Thunderbird (複数形 Thunderbirds)
thornbills
thornbills
スズドリ
bellbirds
the hornet
the act of killing time
woodpeckers
くび
a cocoon
駆けくら