@Volphin: To answer your question about the 8v start by the PowerMaster:
The Postwar ZW's variously started with either 6v or 8v on the 3d rail. This was provided by a separate coil of this voltage wound on the core leg opposite to the variable voltage coil (a 14v coil of 42 turns of #13-square wire (equivalent to #12 round copper) on which the carbon rollers tracked in an arc. The few coils I measured had 6v output. I suspect but do not know if 8v coils were provided for use with locomotives having the taller or longer stack of field laminations in the Lionel single field winding open-frame 3-pole motor. such as the prewar scale Hudsons.
In this case then, the iron field would become saturated at 6v (or 8v in the larger motor?). At this point, the torque output becomes linear (so many gram-centimeters per each added volt input). This is also the approximate point at which the torque is high enough that the engine will move with any added voltage, and each added volt produces the same amount of increased speed.
There is a safety factor involved with these coils enforcing a maximum step-up ratio from low-side terminals to line-plug blades disconnected in error, should one of two phased ZW's become interconnected to the hot low-side output of the second. This would happen if a locomotive were parked in neutral with its metal double-roller pick-up frame straddling an insulated 3d-rail joint between the two outputs, for example. It has been reported here (or elsewhere, I having lost the reference) that the maximum voltage on the blades would rise to 167v. Well, that is better than 277v, the phase to neutral voltage of a 480v 3-phase system, and the most dangerous voltage in America (to electricians). It is commonly found in the ceiling fluorescent lights of supermarkets. GSA has a policy of discouraging its use in Federal buildings.
In a possible control use, the electro-mechanical E-units generally do not drop out until below 6 volts. This may enable an automatic stop system preserving direction by an internal transfer (by overlapping contacts (make before break)) from say, the A output to the B output at its lowest setting-- or slightly higher if required. This requires a trial setup to verify practicality, or research to find a report on such an arrangement.
Finally, there is the touch voltage issue. There is also a 5v coil applied thru the drop of a rectifier aided by a resistant wire which adds a DC offset to one side of the AC sine wave. This makes the output voltage 5vac +14vac +5vdc* +1vac(1954 change to 120v) +1vac(5% overvoltage tolerance), total 30vac-rms. Recently the NEC agreed to make this uniform; previously parts of the Code had used 32vac as the touch limit. [* This 5vdc is actually 5vac applied to only one side of the wave; its lever has a double contact that cuts the resistance wire offset out of circuit at full lever travel.]
It would appear the Lionel Powermaster is implementing a modern Lionel expression of the starting voltage as an 8v start shark-fin wave. Maybe to add more zero volt space into which to add the expanded Legacy control code set, to the list above. The modern era practices seem to be trending to retaining 2 volts clear of the 30-volt touch limit-- fitting a new purpose to older practices... . --Frank