V < Z or Z>V
The 25v Z is the 20v ZW's poppa (Z-no whistle) (They share a breaker at the least ) "Kings"
The smaller amp V is the VW's poppa. And also the KW's( the VWs half brother). Equals, but different set ups.
Looking at a post diagram, and picture of the controls says the rest on acc. and throttles.
It's an era styling thing mostly, prewar/postwar controls.
The top throttle voltage may be higher on prewar transformers (25v). The internal whistle control transformers of postwar reserve 5v from the throttle except during whistling; to combat the whistle motor draw slowing the loco.... (prewar used external whistle boxes/buttons that ate 5v ) Some prewar locos like that whole 25v fyi.