Submitted by peopleneedaplacetogo, who says:

This, from 1979, is the first published version of the now-familiar Michael Hertz Associates-designed New York Subway map, which replaced the (in)famous diagrammatic Vignelli map of the early 1970s.  While most of the design decisions are still reflected in the subway map today, it’s interesting to see what’s changed over the intervening 35 years.  The 1979 map is somewhat less geographically distorted, the distinction between express and local services is drawn slightly differently (with coloured tickmarks for local and coloured circles for express, even at stations where only “express” trains stop), and since most subway-bus transfers were not free back then, the few bus routes that did offer free transfer are shown prominently (these were mostly bus routes that had replaced previously-existing subway services, in some cases 60+ years before this map was published).

Transit Maps says:

It’s funny how we call this the “same” map as today’s version, because there’s a lot of differences, both big and small. The Beck-style tick marks for local stations as mentioned above, no Staten Island inset, the biggest legend box I’ve ever seen, the colours used for water and parkland… the list goes on!

And it’s not just visual either, as the production methods have changed from laborious hand-crafted cartography (Lightboxes! Rubylith! Scalpels!) to modern digital techniques and software. Converting this map to a digital format for the first time must have been fun!