Hi Woodie,
I tried to understand why they built the NYC P-2 as such a contraption with those 'thingies' in front. Here are my ideas - they could even be right (so I hope).

Comments are welcome.
To guide a loco through the curves and turnouts, it is always better to have a set of leading wheels in front of the driving wheels. The driving wheels are somewhat stiff, and going through a diverging turnout on a 0-6-0 or 0-8-0 is a very jerky affair! (That's why switchers are restricted to fairly low speeds!) A leading truck rolls much softer into the curve and then (by the help of springs and levers) it pulls the drivers gradually into the curve, too. This enhances the safety considerably. :thumb:
One leading axle is better than none, but a four-wheel truck is still much better, especially at higher speeds. Unfortunately each additional axle rises the price of the loco. That's why the slower freight locos mostly only have two leading wheels: 2-8-0s, 2-8-2s, 2-8-4s. On passenger locos they went for four-wheel trucks early, from the old Americans 4-4-0 up to 4-6-2s and 4-8-4s.
A 'classic' for passenger trains was the Ten-wheeler, 4-6-0. So I guess that the engineers who constructed the P-2 thought of an electrified 'double-Ten-wheeler' 4-6-0 + 0-6-4, making a good runner in both directions.
And why the porches? Lots of weight on the drivers is much more important for traction than weight on the leading trucks. So they concentrated the heavy hardware (transformers and traction motors) over the driving axles in the center, where it added to the pulling power.
And I suppose, that the brake stands on the front porch only acted on the leading trucks. So when the P-2 was parked soewhere, the brakemen could prevent her from 'walking away' without even entering the cab of the loco. This is a wild guess - perhaps some NYC specialist could enlighten us about this...
Phew - end of my dissertation!
Ron