I think it has huge potential, but needs some serious consideration and touching up here and there. The omnipresent octogenarian from the other board gave his seal of approval to the route and the author has moved on the a new route. This probably means everybody is left to fend for himself, which is a pity, for it is a great route that can only get better by giving it some service.
Here are two simple point to point test runs I used in evaluating the route for prototype like operation, my purpose with TS2012.
Aliquippa to McKeesport is my first ever attempt to write a scenario. You leave at dawn and are expected to arrive some 75 minutes later. There is only one other train scheduled, it runs the same route as your player train but in opposite direction. Expect to meet it somewhere halfway. Your train is restricted to 35 MpH by employee timetable and you will be penalized for speeding at the control points. Due to some flaws in the signalling I don't even think it is possible to earn the green tick, unfortunately. You have to tab your way across a few sticking reds and even then get a SPAD penalty.
I don't like the use of the same size of switch for each and every turnout, and since your empty player train has lesser priority, you are forced to take siding or the secondary main.
Since there is no distinction between track speed, medium speed and low speed turnouts and neither the signalling nor speed signs are of much help, stick to this employee timetable rule: all diverging routes are 15 MpH! Look ahead with the HUD and use the "9" key often when you've never run the P&LE before. So expect to slow down upon entering and leaving single track sections: at Montour Junction, in and out of J&L Tunnel, up and down from the Rankin bridge over the Monongahela river and on leaving and entering any yard.
The return scenario McKeesport to Aliquippa has you in the cab of a 10000 tons loaded coal train with DPU assistance. This train has a higher priority and is routed through straight and clear but limited to 30 MpH all the way by ETT rule. Expect to arrive in Aliquippa at the fall of dusk, the yard is nicely lighted. In typical newbie fashion I have grown a little bolder and have crammed in as much opposing, parallel and crossing traffic, none of which should interfere with your player train. There should be some nice parallel running with neighbour NS on the "Mon" line and a good meet under the Ohio Connecting bridge. In order for the staged moves to have their maximum effect try to stay at 30 MpH as close as possible since I don't know yet how to trigger AI trains and didn't risk interfering with the player train. So essentially it is just a show run, good for showing off the immense possibilities this route has to offer. Excitements sinks a little past McKees Rocks and once past Montour Junction there is little left to do or see before entering Aliquippa.
I don't know yet how to provide background information and/or documentation with a scenario, other than through inserted scenario markers. The route as is comes with only a few waypoints and markers. I intend to change the milepost markers for real railroad waypoints and cabins, as I have gathered quite a lot of material on the P&LE, including ETT's, track charts and detailed maps.
All rolling stock is default, so expect lots of boring black units. All yards are left mostly void of rolling stock because of already very low framerates. Since there are no portals provided, all AI trains stay in the game from start to end. Hopefully they behave like they should on your computers.
I found there is a great lack of plain and common freight cars, no proper 3 bay hoppers, ore jennies, mill gondolas or flatcars come with the game. Cars essential for an industrial layout like the P&LE have to be acquired from elsewhere and then often come with the wrong road names for an eastern to mid-western layout.
Road names are as follows:
CSX and NS obviously, MC = Monongahela Connecting, URR = Union Railroad, M = Montour, PCY = Pittsburgh, Chantiers & Youghiogheny, MKC = McKeesport Connecting, WLE = Wheeling & Lake Erie, BLE = Bessemer & Lake Erie. A few bright UP excursion trains pull into P&LE's 22nd street station to break the monotony of freight trains.
You can substitute the boring blacks into the new repaints of late with your RW_Tools to your own liking.
The scenario comes in a rwp package, so can easily be removed by the package manager.
I plan to take it apart and substitute real dispatcher/train order parlance later and combine it with your critique and comments for hopeful inclusion in the RWA library.
I don't know the criteria for inclusion in the RWA library or if this scenario is up to scratch or even playable. What is the acceptable timespan or attention span of the typical player for instance?
P&LE puts a huge demand on TS2012 due to its size and lovely detail but once fps drops below 14, time is being stretched

So please download from here and tell me how it goes on your install, your mileage will vary.
http://www.mediafire.com/?83ccbhltidmmtwc