Railroads are fundamentally an industrial operation. Only a few are intended to be scenic; that's usually not the purpose for building the railroad. So it's the kind of thing that will run through the poorer and less-scenic parts of town, because it's an undesirable land use and attracts others. Be thankful for the more scenic parts of the line, in the country, and enjoy.

As for the mountains in N. Calif. - if the Starlight is on time southbound (he said that he rode from Portland to LA), the route segment through the mountains and Central Valley, between Klamath Falls and Sacramento, is overnight. Leaving Portland in the morning, and arriving in Sacramento around 0600, should be a clue to the non-geographically-challenged? Complaining about it might not be advanced cluelessness, but a certain amount of it's present.

Modern Amtrak isn't great. This Youtube doesn't add value.