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

HO HOn3 LAMBERT SHINOHARA CODE 70 6 LEFT HAND TURNOUT SWITCH TRACK II I
HO HOn3 LAMBERT SHINOHARA CODE 70 6 LEFT HAND TURNOUT SWITCH TRACK II I
$38.00 (7 Bids)
Time Remaining: 1h 15m
ON3 CONVERSION FROM BACHMANN 2 6 0 BRASS TRUCKS NARROW GAUGE CS
ON3 CONVERSION FROM BACHMANN 2 6 0 BRASS TRUCKS NARROW GAUGE CS
$119.00
Time Remaining: 1h 41m
Buy It Now for only: $155.00
FROM an UGLY DUCKLING to a GORGEOUS SWAN
FROM an UGLY DUCKLING to a GORGEOUS SWAN
$49.99
Time Remaining: 2h 42m
Buy It Now for only: $49.99
KEMTRON HON3 K 2003 PASS BAGGAGE COMBINE 212 RARE KIT UNTOUCHED
KEMTRON HON3 K 2003 PASS BAGGAGE COMBINE 212 RARE KIT UNTOUCHED
$44.95 (1 Bid)
Time Remaining: 3h 18m
BACHMANN SPECTRUM NO 44 6681 MAGNUM TRANSFORMER
BACHMANN SPECTRUM NO 44 6681 MAGNUM TRANSFORMER
$29.99
Time Remaining: 4h 20m
Buy It Now for only: $29.99
Sn3 Berlyn Locomotive Works CS RGS Bettendorf Trucks W Brakes 5 PACKAGES
Sn3 Berlyn Locomotive Works CS RGS Bettendorf Trucks W Brakes 5 PACKAGES
$34.99 (1 Bid)
Time Remaining: 5h 22m
RS O On3 On30 KEIL LINE MODELS 48 125 INDUSTRIAL STIFF LEG DERRICK CRAFTSMAN KIT
RS O On3 On30 KEIL LINE MODELS 48 125 INDUSTRIAL STIFF LEG DERRICK CRAFTSMAN KIT
$103.50 (14 Bids)
Time Remaining: 6h 27m
Bachmann ON 30 item 27391 logging  mining cars skeleton log cars set of 3
Bachmann ON 30 item 27391 logging mining cars skeleton log cars set of 3
$86.00 (4 Bids)
Time Remaining: 7h 1m
RS O On3 On30 SEQUOIA SCALE MODELS BRANCHLINE SAND HOUSE AND BUCKET CRANE KIT
RS O On3 On30 SEQUOIA SCALE MODELS BRANCHLINE SAND HOUSE AND BUCKET CRANE KIT
$32.00 (3 Bids)
Time Remaining: 7h 29m
O SCALE On3 On30 BANTA MODEL WORKS 6153 Oakboro Hay  Grain
O SCALE On3 On30 BANTA MODEL WORKS 6153 Oakboro Hay Grain
$132.00
Time Remaining: 7h 40m
Buy It Now for only: $132.00
Hon3 Blackstone Models DRGW High Side Gondola Road Number 9206  Weathered
Hon3 Blackstone Models DRGW High Side Gondola Road Number 9206 Weathered
$54.95
Time Remaining: 7h 49m
Suncoast Models 004 148 O Scale Logging Camp Craftsman Kit On3On30
Suncoast Models 004 148 O Scale Logging Camp Craftsman Kit On3On30
$56.00 (8 Bids)
Time Remaining: 7h 49m
CHB Models VB 630 148 O Scale Vertical Boiler Kit On3On30 LoggingMachinery
CHB Models VB 630 148 O Scale Vertical Boiler Kit On3On30 LoggingMachinery
$54.95
Time Remaining: 7h 49m
Sierra West 302 148 O Scale Tool Shed Craftsman Kit On3On30
Sierra West 302 148 O Scale Tool Shed Craftsman Kit On3On30
$182.50 (5 Bids)
Time Remaining: 7h 49m
Wheel Works WW 110 148 O Scale On3 Rail Truck Kit OOP
Wheel Works WW 110 148 O Scale On3 Rail Truck Kit OOP
$29.95
Time Remaining: 7h 49m
KMP Models O Scale Steam Powered Sawmill w Planer LumberLogging Interior MIB
KMP Models O Scale Steam Powered Sawmill w Planer LumberLogging Interior MIB
$129.95
Time Remaining: 7h 59m
O On30 Bulldozer Logging Diorama custom weathered after historic pictures
O On30 Bulldozer Logging Diorama custom weathered after historic pictures
$128.00
Time Remaining: 8h 53m
On30 Logging Steam Donkey custom weathered metal wheels lot 2
On30 Logging Steam Donkey custom weathered metal wheels lot 2
$165.00
Time Remaining: 8h 53m
Old Ford Logging Truck custom weathered lot 4  O SCALE  ON30
Old Ford Logging Truck custom weathered lot 4 O SCALE ON30
$118.00
Time Remaining: 8h 53m
Boulder Valley Models 302 Enclosed Cab Dunkirk Geared Steam Locomotive
Boulder Valley Models 302 Enclosed Cab Dunkirk Geared Steam Locomotive
$39.99
Time Remaining: 8h 59m
RS O On3 On30 COLORADO SCALE MODELS 475 LEAVERITE MINE CRAFTSMAN KIT
RS O On3 On30 COLORADO SCALE MODELS 475 LEAVERITE MINE CRAFTSMAN KIT
$93.47 (5 Bids)
Time Remaining: 9h 16m

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Rio Grande K 27 2 8 2 steam loco Japan Westside BRASS HOn3 Narrow Gauge H953
RS O On3 On30 COLORADO SCALE MODELS 475 LEAVERITE MINE CRAFTSMAN KIT
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On30 trains
SPECTRUM NARROW GAUGE LITTLE RIVER LOGGING RAIL BUS On30 Scale TrainNEW
OOn30On3
O On30 On3
SPECTRUM NARROW GAUGE RAIL BUS FULL INTERIOR UNDEC On30 Scale TrainNEW
ALL 11 VOLUMES NARROW GAUGE PICTORIAL
SPECTRUM NARROW GAUGE UNITED TRACTION STREET CAR LIGHTED On30 Scale Train
KMP Models O Scale Steam Powered Sawmill w Planer LumberLogging Interior MIB
RS O On3 On30 ROGERS LOCOMOTIVE SHOP 84 KNEE BRACED WOOD TRESTLE KIT RARE
Narrow Gauge Cumbres Toltec 6 CD PHOTO SET 1300 JPEGS
RS O On3 On30 THOMAS A YORKE O 144 CHINESE LAUNDRY CRAFTSMAN STRUCTURE KIT
RIO GRANDE MODELS DRGW WATER CAR 0470