On: A 100-year-old railway Mexico hopes will rival the...

[bluGill]

Freight travels at many different speeds. There are many tracks in the US that are speed limited to 30mph or less because they have not maintained the tracks to higher standard, even though there are other freight tracks where trains move at 60+mph.

[aksss → bluGill]

Yep, sometimes there are hills that also cause trains to go faster or slower depending on the incline. Fascinating world out there.

Speeds are regulated.. Here's some reading: https://en.wikipedia.org/wiki/Rail_speed_limits_in_the_Unite....)