While in many episodes Walter struggles to remember Agent Farnsworth's first name he correctly calls her by Astrid in the excitement of the watermelon exploding at 27:41.
47 reference: Walter states he stopped counting at 47 needle punches in a victim. 47 is often referenced in the Star Trek shows, and the tradition carried over to Fringe from J.J. Abrams and others.
The glyphs in this episode spell out "burial."
Suburban Station is a real train station but is used by SEPTA, the local public train system. AMTRAK runs out of 30th Street Station which is a little more than a mile west.