Was just on Tri-Rail's website, and found this service advisory:
Tri-Rail passengers should anticipate delays on the weekends, for the remainder of 2012, due to scheduled maintenance work on road crossings. The work is necessary to allow Tri-Rail to implement an hourly schedule on the weekends, beginning on or about March 2, 2013. The South Florida Regional Transportation Authority, which operates Tri-Rail, currently runs trains every two hours on Saturdays, Sundays and holidays.http://www.tri-rail.com/bulletins.htm#list45
For additional information or service updates, call Customer Service at 1-800-TRI-RAIL (874-7245) or log onto www.tri-rail.com. Customer Service hours on the weekend and holidays are 7:00 a.m. to 5:00 p.m.