Joe Clark wrote an interesting and extensive article, Inscribed in the Living Tile - Type in the Toronto Subway, on the history and degradation of typography in the Toronto Subway. 

The Toronto subway has a typographic heritage all its own, starting with a unique font. But, with renovation after renovation and after a series of new station additions, signage and wayfinding in the system are a total mess. The latest “standard” in Toronto subway signage uses fake Helvetica and is a clone of Massimo Vignelli’s work from 40 years ago.

It's a long read, but an interesting one.  [via digg]