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

On3 On30 WISEMAN MODEL SERVICES COLORADO  SOUTHERN PASSENGER COACH 70 KIT
On3 On30 WISEMAN MODEL SERVICES COLORADO SOUTHERN PASSENGER COACH 70 KIT
$99.95
Time Remaining: 3d 55m
Buy It Now for only: $99.95
Box of 12 Peco SL 600 Flexible 36 Flex Track Code 200SM 32 Narrow Gauge Scale
Box of 12 Peco SL 600 Flexible 36 Flex Track Code 200SM 32 Narrow Gauge Scale
$179.99
Time Remaining: 14d 18h 22m
Buy It Now for only: $179.99
On3 On30 WISEMAN SM 108 SHORTY COACH OPEN PLATFORM PASSENGER CAR KIT
On3 On30 WISEMAN SM 108 SHORTY COACH OPEN PLATFORM PASSENGER CAR KIT
$89.95
Time Remaining: 21d 23h 33m
Buy It Now for only: $89.95
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT
$89.95
Time Remaining: 22d 1m
Buy It Now for only: $89.95
On3 On30 WISEMAN MODELS SM 102 DRGW OPEN PLATFORM COMBINE PASSENGER CAR
On3 On30 WISEMAN MODELS SM 102 DRGW OPEN PLATFORM COMBINE PASSENGER CAR
$89.95
Time Remaining: 24d 16h 22m
Buy It Now for only: $89.95
Peco SL E695 Streamline RH Right Hand Turnout Switch SM 32 Narrow Gauge Scale
Peco SL E695 Streamline RH Right Hand Turnout Switch SM 32 Narrow Gauge Scale
$94.99
Time Remaining: 24d 20h 53m
Buy It Now for only: $94.99
Peco SL E696 Streamline LH Left Hand Turnout Switch SM 32 Narrow Gauge Scale
Peco SL E696 Streamline LH Left Hand Turnout Switch SM 32 Narrow Gauge Scale
$94.99
Time Remaining: 24d 20h 53m
Buy It Now for only: $94.99

Other On30 Scale train items recently purchased through this site:

On3 On30 WISEMAN SM 108 SHORTY COACH OPEN PLATFORM PASSENGER CAR KIT
On3 On30 WISEMAN MODELS SM 102 DRGW OPEN PLATFORM COMBINE PASSENGER CAR
Box of 12 Peco SL 600 Flexible 36 Flex Track Code 200SM 32 Narrow Gauge Scale
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT
On3 On30 WISEMAN MODEL SERVICES COLORADO SOUTHERN PASSENGER COACH 70 KIT
Peco SL E696 Streamline LH Left Hand Turnout Switch SM 32 Narrow Gauge Scale
Peco SL E695 Streamline RH Right Hand Turnout Switch SM 32 Narrow Gauge Scale