You’ve already heard about the Yamanote line (can you remember that post?)
The Chuo Line is a little confusing…
The Chuo Main Line (Chuo Honsen) connects Tokyo to Nagoya – covering 424.6 km (or 263.8 miles).
It’s the slowest route and because it’s so long no train runs the entire line. You’d have to get off and change to the next leg of the route.
It’s also so long it’s divided into a east section and west section.
The two trains in Tokyo are the Chuo Rapid (Chu Kaisoku) and the local Chuo-Sobu.
The rapid train has an orange line.
The local train has a yellow line.
Interestingly, the Chuo line is the only train line that crosses through the Yamanote.
Because the rapid train is one of the busiest and fastest running trains it has a bad reputation for being delayed the most due to accidents – intentional or otherwise.
For more detail, wikipedia has a lot of facts and figures for the train otaku in you!