The highest point on the entire New York Central System was on its Pennsylvania Division (Beech Creek District) at Carrolltown, Cambria County, Pennsylvania at approximately 2,130 feet above sea level. It was at the eastern end of the Central's Cambria County Railroad, just west of the Wigton Junction connection with the PRR's Cambria & Clearfield Patton No. 2 Branch.
From Cherry Tree, Pa., the NYC had trackage rights "southward" over the PRR's Susquehanna Extension Branch to Spangler in order to access its "east-west" Cambria County Railroad. And, from Wigton Junction, the NYC again had trackage rights eastward to Patton, where it had an isolated branch off of the Patton No. 3 Branch. From Patton northward, the NYC had trackage rights to Mahaffey Junction, and from there ran "northward" to Clearfield and points east. Just to keep things confused, the portion from Mahaffey Junction to Mahaffey Union Station was essentially under PRR control and was not shown in the 1918 ETT. But, for the half-mile from Mahaffey Union Station to WJ, where it joined the main line, was under NYC control and was shown in the 1918 ETT.
A 1918 ETT
does not show the Cambria County Railroad since all traffic over the line was handled by the PRR (NYC trains, but PRR handled the dispatching), but it was New York Central trackage, so it qualifies. This portion of the New York Central System had no physical connections with the New York Central, only the PRR.
If you go to
http://historicalmaps.arcgis.com/usgs/, enter "Carrolltown, Pa.", click your cursor at the north part of the borough, and then go to the Patton 1904 quadrangle, you'll see the railroad tracks and the elevation markings.
For what it's worth, it's only TWENTY MILES by road from the New York Central's highest point to the PRR's world-famous Horseshoe Curve.