This is a 1950s subway sign box for an R17 "Redbird" subway car. It is a 29" x 9 1/2" box housing a gearing system inside that attaches to the silver crank on the right inner side of the box. This cranks a roll sign that shows two separate readings: one in smaller text on the crank-side of the box (which would appear inside a subway car), and one in a larger text on the exterior side of the box (for the exterior of a subway car). The box dates to 1954, when it arrived as part of the R17 car. Of all the 'redbird' IRT subway cars, this was the only car type to feature individual sign boxes for the routes and destinations separately; later cars used one large steel box with three cranks.
The sign within the box is a 29 foot mylar roll with 30 different readings: 15 printed in large text, and 15 printed in small text. They include all of the numbered subway lines from 1-7, along with different service patterns for the lines (i.e., Broadway Local and Broadway Local-Express for the #1 train).
The roll itself is of particular interest, as it is the only numbered train roll ever printed following the color guidelines of Massimo Vignelli's late-1960s subway system redesign. Trains today carry the colors that were devised in 1979 according to 'trunk' lines, in which different lines share a color based on their routing in Manhattan (the 4/5/6 trains are all green, for example). But Vignelli's system had a color for every train, with a few repetitions. The #4 was pink, for example, while the #3 was teal. The #6 was a bright yellow with white text that proved occasionally illegible, and the #5 was a grey with white text that was similarly hard to read. The colors lasted from 1968 until 1978, but they were mainly present on metal signs--the actual trains tended to keep the original readings from the 1950s/1960s which simply listed a service ("Flushing Express," for example, rather than a #7 on the side).
The roll was printed sometime after 1972 (the 3rd Avenue elevated is not listed) but before the color change in 1979. However, it was modified in the 1980s to match the new colors, so the number bullets that are appear are in the current color system. The text, however, is unchanged, which means that the readings are often unique to this roll. All are set in Vignelli's font of the era: Akzidenz-Grotesk BQ Medium. I've only posted a few photos of the sign, but one is a close-up that highlights the remnants of the old colors. Where there is a darker black and a green circle for the #6 was original a bright yellow circle on a white background, and this is entirely visible on the back of the roll. The close-up is on this yellow circle.
The roll and the box itself were taken out of service in 1988 when the car series was retired once and for all. I acquired it from a subway collector not long ago, and it is remains fully functional to crank and show any of the numbered lines of the city subway system. And, if you look closely, the remains of the short-lived Vignelli colors are still there, too.