The General Railroad Timepiece Standards were adopted by most railroads in 1893. They had to meet the following standards:
A railroad watch had to be open faced, size 16 or 18, have a minimum of 17 jewels, adjusted to at least five positions (see below), keep time accurately to within 30 seconds a week, adjusted to temps of 34 to 100 degrees F., and have a double roller, steel escape wheel, lever set, regulator, winding stem at 12 o'clock, and have bold black arabic numerals on a white dial, with black hands.
Adjustments for a railroad pocket watch movements were described as follows:
- Stem up position
2. Stem left
3. Stem right
- Dial up
- Dial down
- Stem down was included on some watches, but was not required on railroad grade movements.
A pocket watch movement marked only “adjusted” was only adjusted to isochronism and in poise at all temperatures.Isochronism means that the hairspring and balance are adjusted to allow the watch to run at the same rate regardless whether the watch is fully would or almost wound down.So basically there are 9 adjustments for pocket watch movements, which include heat, cold, isochronism, and 6 positions.
Later railroad requirements were more stringent as years passed.