The Collaborative International Dictionary
Petticoat pipe
Petticoat \Pet"ti*coat\, n. (Zo["o]l.) [Petty + coat.] A loose under-garment worn by women, and covering the body below the waist.
Petticoat government, government by women, whether in politics or domestic affairs. [Colloq.]
Petticoat pipe (Locomotives), a short, flaring pipe surrounding the blast nozzle in the smoke box, to equalize the draft.
Wiktionary
petticoat pipe
n. A short, flaring pipe surrounding the blast nozzle in the smoke box of a locomotive, to equalize the draft.