A member of the North Korean military looks at a train with Russian workers, who are going to help in the reconstruction of the Rajin-Khasan Railway, at a cross-border rail link near Tumangang Railway Station in North Korea, Saturday, Oct. 4, 2008.
Retrofitting North Korea's railways would enable increased speeds of 60 mph and heavier loads.
The larger goal could be to position North Korea as a link for trade between East Asia and Europe.
In late April, North Korean leader Kim Jong Un and South Korean president Moon Jae-in made a historic deal to end Cold War-era division.
(Right now it's uncertain to what degree North Korea plans to get rid of its nukes.)
The negotiations, called the Panmunjom Declaration for peace, also include a blueprint for connecting North Korea to the world.