Railworks America

I'm a late comer to Railworks.I didn't get TS2012 until July 4. I have two addon packs I want to get. The G-TraXs Amtrak P42DC Genesis and the PRR K4 Pacific. Both are good looking locomotives, but which is better the P42 or the K4 ?

They are both good. Depends what you like better steam or diesel. P42 also comes with superliner coaches.

Bob is right, they are both good models.
The K4 comes with one steam era standard P70 coach.
The prototype K4 never ventured outside of PRR's rails. Which limits its use to the Northeast Corridor and the Horseshoe Curve routes.
In your fantasy you can run a steam excursion or museum train over any route you want of course.
It is also pretty much alone in US steam locomotive roster, RSC hasn't yet expanded their offerings. Other key steam locomotives are available from G-Trax and formerly IHH, plus some USRA from Britkits.

The Amtrak P42DC roams systemwide over all Amtrak routes and can therefor be used prototypically on all modern era US routes.
The Amtrak includes a complete and good looking modern trainset.

Of all the DLC I own the P42DC is my favorite by far, and I have a fair amount of DLC. It's a fantastic addon.

The P42s sounds are something I'd like to work on after I get my other projects out the door. ES44 and SD70.