Basically v4.0 of my 8-wide GP38-2, but now battery-powered and with correctly scaled trucks. Also some improvements overall.
During my work on v3.0 I quickly noticed the proportions on the engine are generally good, but somewhat off - a slightly too long nose with the cab being too far backwards by just a bit, which also resulted in a too short long hood. Chris Stone later proposed a similar approach to what he did on the SD40-2 redesign: Shift the whole engine body by half a stud in relation to the frame.
Here's the result. Tons of jumpers in there. Proportions are spot-on now. The nose got a plate-height shorter, resulting in a less uncanny face. The cab is shifted forward by half a stud, so the long hood could grow by a stud in length, too. Overall, very happy with the result.
Powered by a single PU L-motor on the rear truck. The front one is unpowered, which came from limitations on the internal space. The city hub runs on PyBricks with the famous train motor control script. The trucks are geared up with a 1:1.67 ratio for some additional speed. Overall, the pulling power is okay-ish with that single L-motor approach, but in general it's probably best to just build a lashup with two identical engines.
Most of the decals are from the BNSF SD40-2 kit available on BMR, I just slapped a different road number on it and used some home-printed yellow striping, also black vinyl tape (better color accuracy). 3D printed train wheels by OKBrickWorks, purchased at BTD.
Thanks once again to Chris Stone for all your input and nudging me into redesigning the engine with that 1/2 stud shift. Best decision ever.
Prototype picture 