I can't help you with your specific problem, but you might find this map more useful since it shows all the rail lines in the Metro system (i.e., Metro Rail, Metro Liner and Metrolink):
http://media.metro.net/riding_metro/...rolink_map.pdf

There is also an app that might be sufficient to overcome your challenges:
http://www.metro.net/mobile/metro-mobile-app/

And an online trip planner:
http://socaltransport.org/tm2_text.php