timz wrote:So no one has found any piece of railroad, no matter how short, that existed before Amtrak, and never carried passenger trains before Amtrak-- but has carried Amtrak scheduled passenger trains?
I think I've found a piece: the Minnesota Commercial Railway's main line between the BNSF and CP lines in St. Paul, now home to Amtrak's MSP Midway Station. I can fairly conclusively say that it never hosted scheduled passenger traffic before 1978.
From what I can tell, two predecessor companies (the Minnesota Transfer Railway and a subsidiary, the Minnesota Belt Line Railway and Transfer Company) operated infrequent mixed trains from New Brighton to a location called "Como Crossing" until 1903
*. Presumably this means the location where Como Avenue crosses the MTR line,
here. Amtrak does not use this track, joining either the ex-GN or the ex-NP mains just south of Como Avenue. Since the Minnesota Transfer's charter only mentioned freight service, the Minnesota Attorney General's office opined that the company was not burdened with providing passenger service. Though the original Minnesota Belt Line Railway and Transfer Company charter did refer to passenger service, the track to the south was not burdened with such a need. I also doubt that any other railroad had scheduled service over its line, as every passenger service between Minneapolis and Saint Paul either ran on the Great Northern, the Northern Pacific, or the Milwaukee Road exclusively.
Not to say that no one ever detoured a passenger train over the line, but I think this is a good candidate for "no scheduled service prior to Amtrak."
*
My source is here, a Google Books scan of a Minnesota Railroad and Warehouse Commission report from 1903.