We've searched the internet and found the largest collection of On30 Scale trains for sale is on eBay. Below are the listings for '2-4-4'.

Bachmann Train DCC Tsunami Plug  Play Sound Module for 2 4 4 2 On30 Loco 44952
Bachmann Train DCC Tsunami Plug Play Sound Module for 2 4 4 2 On30 Loco 44952
$65.84
Time Remaining: 13h 32m
Buy It Now for only: $65.84
Bachmann On30 2 4 4 2 Sound Module 44952
Bachmann On30 2 4 4 2 Sound Module 44952
$85.50
Time Remaining: 17d 8h 19m
Buy It Now for only: $85.50

Other On30 Scale train items recently purchased through this site:

Bachmann Train DCC Tsunami Plug Play Sound Module for 2 4 4 2 On30 Loco 44952
Bachmann On30 2 4 4 2 Sound Module 44952