Why do locomotives have discrete throttle settings?

[blue_streak_1]

Many years ago in Pannama City,Fl there was a bay line Alcoa in a park. Opened the MU connector and it had fewer than 27 points. Maybe 18?.

Cab ride on Amtrak on NYP - PHL commuter train with 2 AEMs train performance terrible. Head unit 95x ? Maintenance went back at stop and cut second unit out. Ran much better. Much later read somewhere that early AEMs did not have notches but used something called “P” control… Not compatible with later 8 notch AEMs. Also read “P” was later eliminated ? Anyone know more ?

[Former_Car_Maintaine]

Many years ago in Pannama City,Fl there was a bay line Alcoa in a park. Opened the MU connector and it had fewer than 27 points. Maybe 18?.

Cab ride on Amtrak on NYP - PHL commuter train with 2 AEMs train performance terrible. Head unit 95x ? Maintenance went back at stop and cut second unit out. Ran much better. Much later read somewhere that early AEMs did not have notches but used something called “P” control… Not compatible with later 8 notch AEMs. Also read “P” was later eliminated ? Anyone know more ?

https://railroad.net/p-wire-question-t77859.html

[CSSHEGEWISCH]

The Bay Line RS1 may have been equipped with the old Alco standard of two connectors with 12 and 21 pins.