Historical clue formulations

• Train system: Abbr. — 2017-05-23
• Train syst. — 2017-04-09
• Freight carrier: Abbr. — 2013-10-20
• The Orient Express, e.g.: Abbr. — 2003-06-14
• Erie Lackawanna, e.g.: Abbr. — 1998-04-30