Here's a thread and a web link by the guy who started the traveling boxcar project (Greg McMurry) that explains the reasons behind the cancellation.
https://ogrforum.ogaugerr.com/t...ling-boxcar-off-line
http://www.trainyard.net/boxcar/join.htm
These were posted/published back in February of 2012 so it's been officially "off line" for over a year.