Possible Clues:

• Short-lived mail system
• 19th-century mail transport
• Legendary mail service
• £25, say, for mail service long ago
• System once used to deliver twentyfive pound couch?
• Old method of long-distance postal delivery in USA
• 19th-century mail delivery service
• Old Missouri-to-California mail system
• Small animal before train was used for postal delivery
• Mail delivery service: twenty five pounds, say