On March 7 at its Oxford location, Bonhams will auction off a 182-lot private collection containing no fewer than 24 antique horse carriages and coaches. If there was any doubt about the exceptional nature of the auction, look to Lot 224. A scarce and coveted mostly original circa-1878 Concord Coach with coachwork by Abbot and Downing, estimated at $240,000 to $270,000 and capable of seating nine passengers, is not even the auction’s top lot.

That honor goes to a circa-1835 traveling landau made by the Lond…