Historical clue formulations

• Caboose, e.g. — 2024-06-19
• Train segment — 2022-07-10
• Training wheels? — 2019-05-26
• Hobo transporter — 2015-05-06
• Track team member? — 2011-11-19
• Part of a track team? — 2009-09-04
• Train part — 2002-11-30