Noisy is a relative term as is the performance of the 970 from car to car depending on the condition of the vibrator, nappy pad, etc. They all do, however, emit noise and far more than their modern L/AF motorized counterparts. I'd liken the noise of a 970 to that of a dog hair clipper depending on the voltage applied to the car, but at 15-18V, for example, they're pretty loud. Here's some relative performance info if that helps.
AF 970 - requires about 12.5V analog AC (direct from 30B) at the rail head to successfully make passes in both directions. Takes about 2 seconds for a one-way trip. Requires about 13.5V chopped AC (via TPC400) to make passes in both directions, also then taking about 2 seconds each direction. Amount of power applied dictates noise level and speed of walking brakeman.
L/AF 6-49023 NYC Pacemaker Walking Brakeman car at about 12.5V analog AC or 13.5V chopped AC is much quieter (I'd say the 970 is about 5X louder) and slower taking about 13-14 seconds in each direction. The amount of power applied has little effect on noise level or speed of the walking brakeman (most likely a voltage regulator at work).
I hope that helps. I have a 6-49023 (car #174226) in EX condition with its original box for sale - $55.00 plus shipping. Click here to see a list containing it and other S and On30/Sn42 items for sale. Thanks.
