What was a result of creating rail standardization?
Railways were able to transport meat without spoilage.
Trains provided cars with pull-down beds for overnight travel.
Trains from different rail lines could use each other’s tracks.
Rail companies began to create their own styles of rails and tracks.

The Answer you need is [Trains from different rail lines could use each other’s tracks]

C) Trains from different rail lines could use each other’s tracks." The trains could use eachothers tracks making the cost and need for more railways cheaper and less time consuming.

for e2020. the answer would be some directions from the mountain range so we can find mt. whitney. to locate which direction is north, you should use a   compass. this would not only find mt. whitney, but also becuase of this long paragraph you would get points because it's not like anyone actually reads your work becuase once they read the first sentence it sounds dumb enough to not read becuase i'm not good at answering this but the answer is compass for your benefit.

for e2020 ; -;