What do different runway depictions mean in the Chart Supplement?
The glossary I'm looking at (page 13 from the current South Central US Chart Supplement) says that that style of dashed line indicates Runway Centerline Lighting.  So runways that have the dashed lines have lights on the runway.

The complete chart supplements are available online from the FAA, and the glossary for each one is easily found about Page 13 for each section.