as Dave know, recently i were working a bit over some Din Schriften Engshrift, which seems to be strongly based on Prussian Railways master drawings. - linked it somewhere at openfontlibrary wiki page ;)
i didn't know Helvetica were that based on Bodoni - would be interesting having some access to the original Haas-Grotesk master drawings, which have some differences from Helvetica (and even more from Helvetica Neue) - the best i could find about Giambattista Bodoni's Manuale TIpografico were here: http://www.rarebookroom.org/Control/bodtip/index.html
