These were probably hand drawn or use a typeface that has no digital equivalent. The answer may be in this exhaustive treatise.

Helvetica?

kel.sey

Stewf thanks for that subway link. Id not seen it before. Yes, the answer is in the article (lettering, not a font)..

As if this plethora of signs were not enough, the subway system also had a bewildering variety of other porcelain enamel and hand-painted signs. The porcelain enamel signs, either hung from the ceiling or posted on the walls, were directional as well as informational. The directional signs included those on the outside of the station entrances as well as those intended for the corridors and platforms underground. Many of the informational signs warned against criminal, dangerous or unhealthy behavior: no peddling wares, no leaning over the tracks, no crossing the tracks, no smoking, no spitting. The directional and informational ones were made by Nelke Veribrite Signs and the Baltimore Enamel Company, while the behavioral ones were the product of the Manhattan Dial Company. Most were lettered in some form of sans serif capitals—regular, condensed, square-countered, chamfered, outlined—though some were in bracketed or slab serif roman capitals. They were usually white letters on a colored background (often dark green for the IND and dark blue for the IRT and BMT), yet many were also black on a white background. There was no house style.

BTW i can also recommend the book Subway Style for an overview of the NY subway architecture and signage,

“Helvetica? kel.sey”

Dear Wording,
there are several reasons by which it is NOT Helvetica.
One is the date of manufacturing.
But you can compare (even at a low size, low resolution) some characters' shapes like ‘7’, ‘&’, ‘C’, ‘M’, ‘R’, ’S’ that are very different than those in Helvetica.

Marcelo Soler

lol i r noob.