ExCon90 wrote:It could be that the double track on the NC vs. single track on the Port Road (albeit with Rule 261) made the difference in view of the number of passenger trains "back in the day." If I get a chance I'll dig out an employee TT from around the 60's and see what speeds were in effect.
Mileage from Baltimore to Harrisburg was 83.4 on the Northern Central vs. 109.0 via the Port Road (using the Columbia Branch from Columbia to Royalton), although the 31.3 miles from Bay View to Havre de Grace were good for 80 -- the wye at Perryville was 15 (this from a Chesapeake Region timetable of 1960). In 1960 the Northern Central had a maximum authorized speed of 55 mph from Baltimore to York and 50 to the Region Post (Phila. Region). Between Baltimore and York there were 9 curves restricted to 30 mph and 19 restricted to 40 (hence the white rings on the line poles, something of a departure for the PRR, which normally didn't have wayside markers for permanent speed restrictions); I don't know how much 55-mph running they got in overall. Street running in York was limited to 4 mph. By 1960 the NC was reduced to single track from Glencoe (south of Parkton) to Cly, where the line joined the Atglen & Susquehanna Branch on the west bank of the Susquehanna. The Port Road had a mas of 40 mph, with 5 curves restricted to 30 mph; there were 3 segments of 2 main tracks aggregating 11.4 miles of the 44.0-mile line. All in all, it looks like they just didn't want to mix freight and passenger on the Port Road. If anyone has public timetables going back that far it might be possible to compare running times via the NC just prior to Agnes and via the Port Road during the short period Amtrak used it.
Another point is that using the NC enabled the Washington and New York sections to arrive and depart Harrisburg simultaneously, while running via Columbia and Royalton would mean one section would have to follow the other.