@Tiffany your loco has a value of "96" in the sound file, byte 0x08. Based on the info you provided (and my past experience), I would guess the gear ratio is 17:1. You can verify this by taking the shell off and turning the flywheel by hand. Make a tiny mark on the flywheel and driving wheel rim so you don't lose count. Turning the flywheel by hand won't hurt the loco, and it's a good way to see if something is binding in the drive train.
Speaking of which, @49Lionel what kind of motor does your 19th Century loco have? I can't help but feel that maybe something is binding on yours, because as John said, the 28:1 locos are usually very smooth runners. The little RS-365 revs to 12000 RPM or more. If the worm gear isn't pressed onto the motor shaft (and unfortunately many of them are , you could probably swap the motor for another one with lower RPM and more torque.
@SanDiegoMark Not sure if this helps, but do you know the "sampling period" for the tach sensor? The scaling factor supports the speed as well as the odometer function. In order to know the loco's current speed, Protosounds has to poll the sensor every second, every half-second, etc. If 0x08 by itself is the scale factor, then multiply the static value by 1408 to get stripes per scale mile. Multiplying 0x08 by about 0.4 gives the number of stripes per second, per smph (in other words, the expected number of stripes per second at 1 smph.) Higher values indicate a slower, smoother-running loco. How does the sensor actually work?