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

Robert Richardsons Rio Grande Southern Chasing The Narrow Gauge VolIII
Robert Richardsons Rio Grande Southern Chasing The Narrow Gauge VolIII
$40.00
Time Remaining: 8h 58m
Gramps UTLX tank car narrow gauge weathered Blackstone Models HOn3 scale
Gramps UTLX tank car narrow gauge weathered Blackstone Models HOn3 scale
$48.00
Time Remaining: 9h 35m
36028 Roco TT Gauge DBAG18201 Red Steam Locomotive 18201 Analog New  Boxed UK
36028 Roco TT Gauge DBAG18201 Red Steam Locomotive 18201 Analog New Boxed UK
$269.74
Time Remaining: 1d 4h 15m
Buy It Now for only: $269.74
A Century + Ten Of DRGW Narrow Gauge Freight Cars 1871 To 1981 2nd Edition
A Century + Ten Of DRGW Narrow Gauge Freight Cars 1871 To 1981 2nd Edition
$40.00
Time Remaining: 1d 20h 47m
Rio Grande Narrow Gauge In Color Vol1 1947 1959
Rio Grande Narrow Gauge In Color Vol1 1947 1959
$40.00
Time Remaining: 2d 20h 53m
AY76 05 10 x Utz Fama Roco AlpinLine Gauge 0 m 145 DC 90 5107 Track MINT
AY76 05 10 x Utz Fama Roco AlpinLine Gauge 0 m 145 DC 90 5107 Track MINT
$36.97
Time Remaining: 2d 22h 2m
Buy It Now for only: $36.97
BINKLEY KIT BUILT HOn3 NARROW GAUGE DENVER RIO GRANDE DRGW BOX CAR WAGON 315 nd
BINKLEY KIT BUILT HOn3 NARROW GAUGE DENVER RIO GRANDE DRGW BOX CAR WAGON 315 nd
$68.98
Time Remaining: 3d 17h 19m
Buy It Now for only: $68.98
SPECTRUM NARROW GAUGE  LITTLE RIVER LOGGING  RAIL BUS  On30 Scale TrainNEW
SPECTRUM NARROW GAUGE LITTLE RIVER LOGGING RAIL BUS On30 Scale TrainNEW
$129.97
Time Remaining: 6d 11h 48m
Buy It Now for only: $129.97
SPECTRUM NARROW GAUGE  GREEN BRIAR  BIG RUN  RAIL BUS  On30 Scale TrainNEW
SPECTRUM NARROW GAUGE GREEN BRIAR BIG RUN RAIL BUS On30 Scale TrainNEW
$129.97
Time Remaining: 6d 11h 57m
Buy It Now for only: $129.97
SPECTRUM NARROW GAUGE  GREEN BRIAR  BIG RUN  w SOUND  On30 Scale Train NEW
SPECTRUM NARROW GAUGE GREEN BRIAR BIG RUN w SOUND On30 Scale Train NEW
$239.97
Time Remaining: 7d 2h 31m
Buy It Now for only: $239.97
AY100 05 3x Utz Fama AlpinLine Gauge 0 m DC 5251 Gradient running track MINT
AY100 05 3x Utz Fama AlpinLine Gauge 0 m DC 5251 Gradient running track MINT
$28.46
Time Remaining: 7d 5h 31m
Buy It Now for only: $28.46
AY98 05 3x Utz Fama AlpinLine Gauge 0 m DC 5251 Gradient running track MINT
AY98 05 3x Utz Fama AlpinLine Gauge 0 m DC 5251 Gradient running track MINT
$28.46
Time Remaining: 7d 6h 42m
Buy It Now for only: $28.46
SPECTRUM NARROW GAUGE  RAIL BUS  FULL INTERIOR  UNDEC On30 Scale TrainNEW
SPECTRUM NARROW GAUGE RAIL BUS FULL INTERIOR UNDEC On30 Scale TrainNEW
$129.97
Time Remaining: 9d 9h 35m
Buy It Now for only: $129.97
BINKLEY KIT BUILT HOn3 NARROW GAUGE COLORADO NORTHERN CN ORE WAGON
BINKLEY KIT BUILT HOn3 NARROW GAUGE COLORADO NORTHERN CN ORE WAGON
$138.67
Time Remaining: 9d 22h 16m
Buy It Now for only: $138.67
Narrow Gauge Cumbres  Toltec 6 CD PHOTO SET 1300 JPEGS
Narrow Gauge Cumbres Toltec 6 CD PHOTO SET 1300 JPEGS
$29.99
Time Remaining: 11d 1h 40m
Buy It Now for only: $29.99
ULRICH O SCALE 1 48 On3 On30 FORD CAB  CHASSIS NARROW GAUGE ALL METAL
ULRICH O SCALE 1 48 On3 On30 FORD CAB CHASSIS NARROW GAUGE ALL METAL
$49.99
Time Remaining: 11d 5h 27m
Buy It Now for only: $49.99
ULRICH O SCALE 1 48 On3 On30 FORD CAB  LOGGING TRAILER NARROW GAUGE ALL METAL
ULRICH O SCALE 1 48 On3 On30 FORD CAB LOGGING TRAILER NARROW GAUGE ALL METAL
$69.99
Time Remaining: 11d 6h 52m
Buy It Now for only: $69.99
ULRICH O SCALE 1 48 On3 On30 FORD TANDEM CAB  CHASSIS NARROW GAUGE ALL METAL
ULRICH O SCALE 1 48 On3 On30 FORD TANDEM CAB CHASSIS NARROW GAUGE ALL METAL
$52.99
Time Remaining: 12d 3h 46m
Buy It Now for only: $52.99
Tillig 85637+ Tillig 85638 H0E Pair of Switches Right+Left for Narrow Gauge H0E
Tillig 85637+ Tillig 85638 H0E Pair of Switches Right+Left for Narrow Gauge H0E
$50.97
Time Remaining: 12d 10h 12m
Buy It Now for only: $50.97
BINKLEY KIT BUILT HOn3 NARROW GAUGE DSPPRR DENVER SOUTH PARK REEFER BOX CAR 605
BINKLEY KIT BUILT HOn3 NARROW GAUGE DSPPRR DENVER SOUTH PARK REEFER BOX CAR 605
$68.98
Time Remaining: 13d 1h 39m
Buy It Now for only: $68.98
BINKLEY KIT BUILT HOn3 NARROW GAUGE COLORADO NORTHERN CN TRACK CLEANING WAGON nd
BINKLEY KIT BUILT HOn3 NARROW GAUGE COLORADO NORTHERN CN TRACK CLEANING WAGON nd
$124.73
Time Remaining: 13d 13h 43m
Buy It Now for only: $124.73

Other On30 Scale train items recently purchased through this site:

Robert Richardsons Rio Grande Southern Chasing The Narrow Gauge VolIII
SPECTRUM NARROW GAUGE GREEN BRIAR BIG RUN w SOUND On30 Scale Train NEW
SPECTRUM NARROW GAUGE UNITED TRACTION STREET CAR LIGHTED On30 Scale Train
Narrow Gauge and Short Line Gazette Magazine lot of 13 Model Railroad 1979 1981
Gramps UTLX tank car narrow gauge weathered Blackstone Models HOn3 scale
Bachmann On3 NARROW GAUGE EXPRESS TRAIN SET 25005 Great Northern NEW
Narrow Gauge Cumbres Toltec 6 CD PHOTO SET 1300 JPEGS
SPECTRUM NARROW GAUGE RAIL BUS FULL INTERIOR UNDEC On30 Scale TrainNEW
BTS 17143 On30 Laser Cut Narrow Gauge Cheat Run Trestle Craftsman Building Ki
SPECTRUM NARROW GAUGE LITTLE RIVER LOGGING RAIL BUS On30 Scale TrainNEW
ULRICH O SCALE 1 48 On3 On30 FORD CAB CHASSIS NARROW GAUGE ALL METAL
SPECTRUM NARROW GAUGE V DUMP MINING LOGGING CAR On30 Scale mint
Westside Model Company HOn3 Narrow Gauge Brass Trucks 1 Pair NOS
ULRICH O SCALE 1 48 On3 On30 FORD TANDEM CAB CHASSIS NARROW GAUGE ALL METAL
SPECTRUM NARROW GAUGE GREEN BRIAR BIG RUN RAIL BUS On30 Scale TrainNEW
AY100 05 3x Utz Fama AlpinLine Gauge 0 m DC 5251 Gradient running track MINT
ULRICH O SCALE 1 48 On3 On30 FORD CAB LOGGING TRAILER NARROW GAUGE ALL METAL
AY76 05 10 x Utz Fama Roco AlpinLine Gauge 0 m 145 DC 90 5107 Track MINT
ALL 11 VOLUMES NARROW GAUGE PICTORIAL
Tillig 85637+ Tillig 85638 H0E Pair of Switches Right+Left for Narrow Gauge H0E
ay81 0 5 10 x Utz FAMA Roco alpinline Gauge 0 M 145 90 5207 Rack Rail
New Spectrum Narrow Gage On30 Camp Car Bunk Car 26998
ay93 0 5 3X Utz Fama alpinline Gauge 0 M DC 5252 Slope Spout Track MINT
36028 Roco TT Gauge DBAG18201 Red Steam Locomotive 18201 Analog New
AY71 05 10 x Utz Fama Roco AlpinLine Gauge 0 m DC 90 5117 Compensation pieceW