Congrats on a beautiful, historic acquisition! I love that the coal bunker is modeled empty. You could do whatever you wish with that.
Almost any 2 rail track will do. As noted the outer tracks will need separated electrically and direction is determined by dc polarity. For a simple test run in a loop Gargraves would do fine despite reservations of some others here. It's all about the shape of the rail head interacting with the profile of the wheels. Traditional o gauge tinplate rails are rounded on top, and simply don't play nice with narrow scale wheels.
Also, and I think you know this but already but just throwing it out there, you need to consider radius if planning on looping around. I wouldn't try anything less than 0-72, 3' radius / 6' diameter on this machine unless it came with paperwork saying something else.
For a traditional dc open frame motor just about any dc hobby transformer meant for O or G gauge should do.
Since you have post war equipment as well I also presume you can apply oil where it looks needed.
Congrats again on a cool find!
Ps. I personally would keep it original, but if you want it to run on 3 rail track there are several options if center rail pickups are installed. Easiest would be a reverse unit such as a high amp Dallee offering. It would still need non- tubular rails though