PRR Grade Separations on Harrisburg Line

I rode AMTRAK's "PENNSYLVANIAN" from Pittsburgh to Newark on March 5, and was looking specifically for former PRR grade separations from Thorndale east. Here is what I noted:

(1)At Thorndale, a subway west of the station still contains a rusty track. Was this the eastern end of the Low-Grade Line from Thorndale to Enola Yard? If so, and as the line has been abandoned for some years, what are any rails at all still doing there?

(2)At Parkesburg, there was another grade separation, but I did not notice any rails on it. Which line joined the main line here?

(3)Just west of Exton, there was a large bridge across the PRR mainline. Just north of Exton station, not far east of this bridge, there was a ROW on a large fill which no longer had tracks on it. Which railroad and line was this?

(4)Where does the Trenton Cutoff join the main line? Is the track still in on this line all the way? What service does it still have?

Thanks for answers to these questions.

The east end of the A&S ducks under here

http://www.bing.com/maps/?v=2&cp=39.956 ... l=17&sty=a

You might as well use such aerials to pin down the spots you're asking about. The old topo maps will make it clear which spot was which RR.

Don,

2) This may have been the line that went to Columbia, on the Susquehanna River.

3) This is the former ROW for the P&T line, often mistaken for part of the Trenton Cutoff.
http://www.railroad.net/forums/viewtopi ... 15#p599442

4) In Frazer (Glen Loch)

Until sometime in the 1950s, PRR had the continuous 4-track main line west from Zoo for 50+ miles; passenger trains ordinarily used the outside tracks. So at any location where the double-track low-grade line joined the main line it joined the two inside tracks-- hence the flyovers.

Proceeding eastward on the low-grade line, we swing alongside the main line at Atglen, maybe three miles west of Parkesburg. We continue parallel to the main, climbing 0.3% while the steeper main line gains altitude that will allow the two eastward main-line tracks to fly over the low-grade at Parkesburg. Eastward from there to Thorn, no separate low-grade line, just the 4-track main (and a yard between the eastward and westward tracks).

At Thorn the low-grade line resumes, between the eastward and westward mains as usual. The two eastward mains duck under it http://tinyurl.com/yevmb6u and the low-grade diverges southward for a few miles to maintain its 0.3% maximum eastward grade. It crosses over the main line at the huge thru truss at Whitford, then stays parallel to the main on the north side for a couple more miles until it joins the Trenton cutoff http://tinyurl.com/y9l8ltq

The Trenton cutoff is older than the low-grade west of there-- so where it joins the main line (by ducking under the two westward main line tracks) was originally the west end of the low-grade line. Apparently PRR considered it wasn't worth it to build connections for an eastward low-grade train to get back on the main line there-- so an eastward train to Philadelphia would take the main line east from Thorn.

Red Arrow Fan wrote:2) This may have been the line that went to Columbia, on the Susquehanna River.

You could get to Columbia by using the Atglen & Susquehanna and then the Columbia & Port Deposit, but you probably mean the line from Dillerville, just West of Lancaster on the Main Line, direct to Columbia.
The grade separations at the West end of Rockville bridge; West of Middletown, near the airport; and at Morrisville are also part of this project.