We've searched the internet and found the largest collection of On30 Scale trains for sale is on eBay. Below are the listings for 'observation car'.

ENHANCED Bachmann On30 Observation Car Painter of Light
ENHANCED Bachmann On30 Observation Car Painter of Light
$95.00
Time Remaining: 14d 16h 24m
Buy It Now for only: $95.00

Other On30 Scale train items recently purchased through this site:

ENHANCED Bachmann On30 Observation Car Painter of Light