This took most of the morning and into early afternoon, but only because in addition to making it into a calf, I removed the motors and boards, making in a dummy calf. Reason: the motors are identical to those in EZ-Street vehicles but have a flywheel. Since I have a powered "A" unit, I could make this a dummy and get two flywheel motors to play with:'Streets vehicles benefit a lot from having a flywheel, the only deficiency I see in their design, frankly. I have fit larger motors with flywheels, but a stock size motor with flywheel will come in handy. I removed the boards, too, for use elsewhere and another time.
Here they are moving . . .
I am generally pleased with the result of how the calf looks. I will probably order vinyl sticerk numbers in the ATSF font for "465b" for it.
REMOVING THE MOTORS WAS A MISTAKE. Before modification, I briefly ran the pair (both converted to series motors) together and with both powered they were a sweet pair, pulling six cars and a caboose nicely. But now, with only a single powered unit, and it with only two driven axles, it can pull its equal-weight partner calf, and only one or two cars around 36" curves, before it spins its wheels - and it spins them badly trying to get up a 3% grade - badly. Not a good train. But it looks good, and fun, and it was a fun project.
I had a couple of request for pictures during the conversion, so . . .
Start by removing the four screws (red arrows) and releasing the four hook tabs that hold body to chassis (yellow arrows). The body pulls off.
But the body won't go very far because of the wires attached its light to the chassis. I converted this puppy to series motors previous, hence the two wires you see on the motor control board sticking up, cut.
The cab removes from the body. Just pull it out at both sides and it pushes off . . .
I removed the signel figure and mounted it as a second operator in the other 44-tonner.
I made the follow cuts. At the top, widening the gap enough to get past the end partitions, so I have clear air to inside right below the body roof. At the sides, I trimmed the plastic a bit.
I built a bridge across the top, from under both sides of the body casting, using white styrene sheet cut to size.
And sdid similarly at the sides.
I cut, fit, and grooved a 1/10 inch piece of styrene to fit as the top, seen here.
I made sides as seen here, this is white styrene too, just from a piece that was painted flat black on one side. I scribbed panel seams and attached tiny door handles . . .
The stacks pried right off the cab casting. I cut each (black part below) and glued 1/2 of a plastic tube (5/16 dia) and sanded and smoothed the seams a bit . . .
And attached them in place.
Then masked the past I won't repaint . . .
Priming it (Rustoleum spray gray)
Initially I did it flat black, but that was too flat . . . I went ahead, mounted it, and completed the railings.
Then went back and removed the body, remasked, and sprayed it satin black. Silver line at the top was hand painted.
Nice project - nice pictures and description. My only question is why put a second operator in the cab when the purpose of the 44 Ton diesel was to get past the requirement for two operators for any engine over 45 tons? I know, it's your world and you can run it as you like. I answered my own question and I agree. 
