Miss Callahan Comes to Grief by James Hadley Chase

This is the story of Miss Callaghan. Not of any particular Miss Callaghan, but of the hundreds of Miss Callaghans who disappear from their homes suddenly and mysteriously and are seen no more by those who knew and loved them. This is also the story of Raven, who played with clockwork trains, the leader of the White Slave Ring in East St. Louis, who was responsible for the keeping to full strength the army of women for the service of men.