In 1912, the entire line was upgraded to 87-pound rails.
In 2006, the line was upgraded to allow a service every 10 minutes during peak periods.
They offer a nice and shiny 100mbps line to everyone who is to say that the lines will ever be upgraded in the future?
Between 1911 and 1912, the line was again upgraded.
The line will be extended and upgraded with new stations over the next decade.
At the same time the line was upgraded for a top speed of 160 km/h.
At the same time the line was upgraded to allow higher speeds.
The line has been upgraded several times to increase the axle load.
This meant that the line would be upgraded and electrified.
Over the time the line was also upgraded for higher safety.