After staring at the Superliner set I picked up at S Fest last week, I realized the F40PH needed "something". I also realized it's a 20 year old model locomotive (the date written on the frame inside says 3/21/96.)
First, I replaced the headlight bulb with an LED. The jury's out on if I'll add one to the rear headlight.
Second, the headlight castings needed lenses. (All the better to see that nice new LED shine my dear...) I use fiber optic light pipe I bought decades ago. By carefully heating the end with a soldering iron, it expands and forms an almost perfect lens. It took several heatings to get the ends to fit snug in the headlights. Once that was done, heat was applied inside to expand the pipe and anchor the lenses to the body.
Third, the airhorns have a flat face and no "inside" in the bells. I various sized drills to slowly drilled ever larger opening until I felt it unwise to go further. Not as successful as I would liked because of the nature of the part itself, but I guess it'll do.
Finally, the prototypes had the number on the rear of the unit, easily done with dry transfers. The inserts show the "before" condition.
These subtle changes have improved the looks of the unit quit a bit. When I get in a wire bending mood, I'll add hand rails, grab irons and maybe replace the plastic handrail on the back. The locator dimples for the grab irons on the rear are rather monumental, I don't see any easy way of disguising them, so I'll have to live with them.
Overall, in spite of it's age, the AM F40PH is a pretty good model of Amtrak's former workhorse.
Rusty
But I have two locomotives that have been running since I bought them early in the production run, and show no signs of slowing down. Just a drop of oil now and then and a wheel cleaning once in a while. Sometimes when I get the urge, I double head them with both car sets plus a couple of extra ones. Nice looking train! But you're right in commenting that they're already dated. It kind of makes me sad to see them turned into "cabbages". But even THOSE are disappearing. Heck, the scratch built AEM7 that I made in 2011 is out of date. Amtrak's AEM7's made their last run earlier this year. A friend once told me that eventually "modern" modelers become "period" modelers. 
