Amtrak Railroad Anacostia Bridge
It carries Amtrak's Northeast Corridor and MARC's Penn Line passenger rail traffic . 
<triplet> Amtrak <subj> Northeast Corridor <obj> owner of <triplet> Northeast Corridor <subj> Amtrak <obj> owned by <triplet> MARC <subj> Penn Line <obj> has part <triplet> Penn Line <subj> MARC <obj> part of