checkstring

Noun

 * 1) A cord used by a passenger in a carriage to signal to the driver to slow down or go faster.
 * 2) * 1864,, William Stephens Hayward, Revelations of a Lady Detective, short story "Incognito", George Vickers, Strand
 * I pulled the check-string, and gave him [the coachdriver] his instructions.
 * 1) * 1919, Ronald Firbank, Valmouth, Duckworth, hardback edition, page 4
 * Mrs Hurstpierpoint - the dowager of the gleaming brows - leaned forward all at once in the carriage and pulled the checkstring attached to her footman's arm.