NTSB report on the <a href="https://en.wikipedia.org/wiki/1996_Silver_Spring,_Maryland,_train_collision" class="extiw" title="w:1996 Silver Spring, Maryland, train collision">1996 Silver Spring, Maryland, train collision</a>.
National Transportation Safety Board
<a rel="nofollow" class="external free" href="https://www.ntsb.gov/doclib/reports/1997/RAR9702.pdf">http://www.ntsb.gov/doclib/reports/1997/RAR9702.pdf</a>