Question Concerning Old IRT Signals

[Blake McNamara]

I rode the Flushing Line often before CBTC was installed and noticed that there appeared to be very elderly looking block signals which were rounder and larger than the other signals on the line. When doing research on the IRT and its El lines, I noticed that these signals seemed to be exclusive to the IRT and appeared to be perhaps from the 1920's or so. In pictures, they seemed to be often found on lines that still had semaphores (i.e. original El lines and the Jerome Avenue Line). They appeared to have dwindled quite a bit over the years but by the 1990's remained on the Pelham, White Plains Rd., and the Flushing Lines. I realised that the Pelham Line was the last place where they had the double-headed interlocking versions of these signals from some blurry pictures. Anyway, I would like to know more about these particular signals, for instance who manufactured them and when they were manufactured as well as whether or not they were used in the tunnels. Also if anyone has any pictures of the Pelham signals before the line was resignaled, it also be greatly appreciated.

Here are pictures: