Alaska Air Cargo has been having a tricky time with its new freighters.  These are conversions of some of its older 737-800s and will provide more capacity than the current 737-300BDSF fleet.  I got the first of the jets not long after it arrived, but it then was out of service for ages.  They have finally got it in regular use now but the delivery of the second aircraft was delayed while they sorted things out.  It is now delivered and operating regularly, and I caught it climbing out of SEA one weekend.  The second shot is the same airframe back when it was in passenger service a few years ago.