Like i said in an earlier post here, the PL42AC is essentially a purpose built single ended replacement for the F40PH's, GP40FH's and GP40PH-2's. Even the prime mover is simply a newer model of the lineage used in the geeps.
I personally have witnessed a 4300 series (i think it was 4301) hauling serious ass west past levittown station on track 4 with an ACL set of comet 4's. It was going about 90 i'd estimate.
The combination of where these (the geeps and PL's) revenue locomotives usually run and the "built in" speed limits on those tracks plus the amtrak speed limits when they run on the NEC mean they never really get to rocket around like the electrics do, unless it's on a move like the one stated above.
Now, the ALP-45DP on the other hand was purpose built from the rails up to pul 12 multilevels up to 125 mph. The MLV's are not cleared for over 100 mph at this time so that is moot. My GUESS is that amtrak will allow these to run up to 100 once they enter service on the NEC/NJCL, and in the future, as with the ALP-46a, could possibly, with the certification of the MLV's, to run at those higher speeds. Knowing amtrak, they may put location specific speed restrictions here and there to reduce track wear, but again, just my guess. We will all just have to wait and see. Folks at amtrak are not stupid, they know these locos are a serious monetary investment for NJT and represent an opportunity for NJT to really use all of this equipment to its maximum potential and really turn their system up a few notches. And, amtrak is upgrading a huge chunk of NEC within NJ, and i think that will ultimately be where these locomotives (both the 45 and 46a) get to go up over 100.
One last point, is that most of if not all of track 1 and 4 is not rated higher than 110 running, and a huge amount of NJT moves are on track 1 and 4, so that definitely plays a roll.
It would be awesome to see them in service on all the different lines used to their full potential. At the end of the day these units are doing work to get people places and them working properly and moving trains on time is what matters.
Next stop the square, journal square station next!