When plotting out the bigger pieces of content in my job, I love talking about through lines—the strands that weave through a proposal or an interview presentation, the recurring motifs or differentiators that draw readers or attendants from start to finish.
Looking up through line in the OED, I discovered that the origin of the metaphorical use is exactly as fun as I expected:
2. A railway line that covers a whole route without requiring passengers to change trains.
1843 Sheffield & Rotherham Independent 4 Mar. 3/3 That is a subject which need not interfere with the amalgamation and continuity of the through line.
1866 Railway News 6 Jan. 6/1 With this line completed a connection could be made.., opening a new through line from Pittsburgh to Philadelphia.
1964 Mississippi Valley Hist. Rev.50 598 Taking advantage of depression conditions following
1873, railroad officials..completed the first through line from New Orleans to Chicago.
2005 Railway Mag. July 6/4 The reopening of the through line means that Thameslink has now vacated the interim St Pancras station.
In the 20th century, the original sense of the term was adapted for metaphorical use, though—rather oddly—the first instance in English that the OED indicates is actually a translation from Russian of a book by Russian actor and theater director Konstantin Stanislavski:
1936 E. R. Hapgood tr. K. S. Stanislavsky Actor Prepares xv. 258 This through line [Rus. linija skvoznogo dejstvija] galvanizes all the small units and objectives of the play and directs them toward the super-objective.
I wasn’t immediately familiar, but it turns out that this book, An Actor Prepares, and the following two volumes published by Stanislavski (Building A Character and Creating A Role), comprise some of the most influential modern writing on the art of acting and are widely credited with leading to the developing of the Method system of acting.
So, it’s perhaps Slanislavski (and his translator, Elizabeth Reynolds Hapgood) who we have to thank for the popularized metaphorical use of this travel metaphor, a handy way to think about how elements come together to form a larger narrative.
Taylor Coe 