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Howdy Everybody. So, I am planning an O-Gauge model railroad of the East Tennessee & Western North Carolina (ET&WNC) "Tweetsie" Railroad, specifically the Johnson City to Elizabethon, TN portion of the line, which had dual gauge iron (track to accommodate both standard and narrow gauge stock), and my desire is to model this dual gauge track in order to accommodate both O and ON30 Scale trains. however, there is a big issue with my idea: I use 3-rail O-Scale like the the majority of people in this hobby do, so I'm worried about providing enough clearance for the underside of both trains, and to prevent either train from causing some sort of short. My plan is to use either Lionel Super O or Gargraves track due to it's thin 3rd rail. Can any of y'all help me figure out how to make dual gauge iron with 3-rail, O-Scale track? Thanks!

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Why not use 2 rail standaard Gauge?    It will look so much better and you have more options for control systems.   

In either case you are going to have to handly the narrow gauge rail.    Since HO is closer to 32 inch gauge and O standard for most hobbiests is 5 ft or 60 inches,  you narrow gauge rail is going to be almost on top of the center rail.

Are you planning on running down the middle, or use one outside rails for both gauges?  I assume you want to use a common outside rail.

I remember trying this as a kid with my o gauge trains and my brothers' ho stuff.  As stated above, the scale is really close but doesn't quite work out, my brother's trains would always get lopsided and start falling between the rails. 

If you are will to relocate the center rail however, I think the small offset needed to make your ho stuff work would not bother the wide pick up rollers on most 3 rail equipment.  I am not away of commercially available track to do what you want, but I think you are headed in the right direction talking about a thin center track, but if you need to move the center rail I think you are much better off with mth scaletrax or atlas O.  The reason I say this is that Gargraves and super O both have a center rail that is embedded in the tie. Otherwise I think you are totally into custom track from the get go.

Check out this thread for some views of how the various track systems are constructed.

You might consider using Atlas O 3-rail track and re-gauging the wheels on your On30 models. To run the On30 equipment you would then need to convert the AC power into the middle rail by rectifying it to DC within the locomotive (probably difficult) or you could supply DC from a power pack directly across the center-rail and an outside rail (probably easier). Atlas O 3-rail track might be a good choice because the precise flat-top rail cross-section shape might be the most compatible with the small On30 wheels and flanges. You could first test this by re-gauging an On30 locomotive, supplying DC across the center and outer rails, and running... This approach, if it works, would let you run your 3-rail O gauge and On30 equipment without any modification to the track.

MELGAR

Last edited by MELGAR

One other possibility just brainstorming,another possibility comes to mind. It won't be very realistic if your goal is to look like prototype standard/narrow gauge dual trackage, which would have 3 rails, though the inner rail would not be centered as it is on O gauge 3 rail track, then my idea won't work. You could do dual gauge by having 4 rails, with the HOn3 track centered around the middle rail. Obviously, this would cause problems with switches, but given that the middle rail to outer rail is not exact for HO gauge (.625 is O gauge 3 rail spacing between inner/middle rails, .65 is HO gauge track), you might have problems with binding and other issues with the HO gauge wheelsets using the outside and middle rail. 

The other problem with using the middle rail is the  obvious one, HOn3 uses DC. You could put a rectifier in the HOn3 engines, you also would need to be careful with speed control given that AC transformers put out a max of 18v, 12V DC for scale trains. If you wanted to run command control using the shared third rail using DCC I would hazard a guess is possible, but likely would be complicated, too. a 4 rail approach would allow basically isolated power, but allow dual running. The tough part of 4 rail would be switches, not sure if that is even possible (Haven't tried sketching it). 

In any event, I suspect any implementation would require a lot of trial and error and custom fitting. If someone did this commercially, there may be existing track out there at the very least to act as a pattern. 

 

 

jhz563 posted:

Are you planning on running down the middle, or use one outside rails for both gauges?  I assume you want to use a common outside rail.

I remember trying this as a kid with my o gauge trains and my brothers' ho stuff.  As stated above, the scale is really close but doesn't quite work out, my brother's trains would always get lopsided and start falling between the rails. 

If you are will to relocate the center rail however, I think the small offset needed to make your ho stuff work would not bother the wide pick up rollers on most 3 rail equipment.  I am not away of commercially available track to do what you want, but I think you are headed in the right direction talking about a thin center track, but if you need to move the center rail I think you are much better off with mth scaletrax or atlas O.  The reason I say this is that Gargraves and super O both have a center rail that is embedded in the tie. Otherwise I think you are totally into custom track from the get go.

Check out this thread for some views of how the various track systems are constructed.

My plan is to put each HO/ON30 Rail in between the center and outside rail, as I figured that would be the easiest thing to do, and it would allow me to minimize the modification needed to the track, but like I said, my biggest worry if I do this would be clearance for the underside of either locomotive. if the Narrow Gauge rails are too low, than the ON30 engine won't sit correctly on the rails. if the rails are too high, then my O Gauge Engine won't sit on the rails properly. 

Why not go for DCC? DCC typically uses 19v AC. 

Run either the centre, or the common outer rail as one feed, the other as the return and let the O gauge only, outer rail look after itself. 

Regauge the On30 locomotives and stock to suit. I don’t know about in the USA, but O14 is a thing in the UK, with specialist trade support for 14mm Gauge axles and wheelsets.

tweetsie12 posted:

My plan is to put each HO/ON30 Rail in between the center and outside rail, as I figured that would be the easiest thing to do, and it would allow me to minimize the modification needed to the track, but like I said, my biggest worry if I do this would be clearance for the underside of either locomotive. if the Narrow Gauge rails are too low, than the ON30 engine won't sit correctly on the rails. if the rails are too high, then my O Gauge Engine won't sit on the rails properly. 

Use the same size rail.  If you buy 2-rail Atlas, buy enough extra to strip the rails off some of the sections and glue tot he ties at the right gauge.  You'll need to get an HO gauge tool (or 3), but they are cheap and plentiful.  Again, it's the switches that create the complications.

Rockershovel posted:

Why not go for DCC? DCC typically uses 19v AC. 

Run either the centre, or the common outer rail as one feed, the other as the return and let the O gauge only, outer rail look after itself. 

Regauge the On30 locomotives and stock to suit. I don’t know about in the USA, but O14 is a thing in the UK, with specialist trade support for 14mm Gauge axles and wheelsets.

My plan is to use DCC. My lone ON30 locomotive (for right now) is already equipped with a DCC Decoder, so that's something I'll take into consideration.

This approach was reported in another Forum post several years ago though the person hand laid his dual gauge track.  I can't remember the details.

These search results will help.

https://ogrforum.ogaugerr.com/...agination.sort=SCORE

Your center rail will need to be offset a few hundreds of an inch to accommodate the 30" inside spacing.  It won't effect the performance of your center pickup roller.

I am not aware of any Gargraves "thin" center rail.  MTH makes their ScalTrack with a thin center rail.

Jan

Being a Two rail, DC, builder myself, any "narrow gauge" will be correctly laid ( HOn42)...none of this Third rail Toytrain stuff...not even 

Maerklin back in the 60s....

Now that I am starting a 1:48 fine scale 0n42 diorama, it too will be 2-Rail DC...no need for DCC unless I add sound. I can't understand why some hobbyists insist on this antiquated 3 rail power system with out of scale wheels, etc. Not proper Model Railroads/Railways at all....I abandoned my Hornby No.O Tinplate Clockwork set back in the Fifties ( rust and dust).

Moved on to HO, Sn42, andnow On42.

Doc AV    Down under. Plop

 

 

As it happens, this very topic came up during the club “Skype session” last week. There was, apparently, once a well-known layout of this type on the U.K. exhibition circuit - this is NOT recent! It was a product of the 1940s-50s era when scratch building was probably at its peak. 

O Gauge 2-rail hadn’t really caught on in U.K. at the time, and O sized insulated wheelsets simply weren’t available at the time. 

The crux of it was that the dual gauge section comprised a centre rail, all as previously described, using the then-new proprietary 16.5mm gauge wheels, O and OO Gauges. All running rail was the same size.

Narrow gauge switches were conventional in construction, but the track plan was constructed so that there were no O Gauge switches within the dual-gauge section, thereby avoiding the problem. 

All junctions where the narrow gauge crossed the centre rail, were wired as “live frog” crossings - ie, bounded by rail breaks forming isolated blocks, so that the whole area took the polarity of the live rail. 

It would be possible to construct O gauge, dual gauge switches with a “fixed frog” - the moving section being confined to the section between the narrow gauge rails - but 2 rail track building techniques weren’t sufficiently developed at the time. 

 

That was all that could be remembered by the group, but it seemed plenty! 

 

A lot depends on how much dual gauge track you need and whether or not you need dual gauge switch tracks. Buy some code 148 brass or nickel silver rail and hand lay it. I would just move the middle rail over so it is in gauge for On30 and see if you have any impact to the 3 rail powered stuff. Considering O gauge is gauged at 60” I do not see you having much of a problem.

Being a Two rail, DC, builder myself, any "narrow gauge" will be correctly laid ( HOn42)...none of this Third rail Toytrain stuff...not even 

Maerklin back in the 60s....

Now that I am starting a 1:48 fine scale 0n42 diorama, it too will be 2-Rail DC...no need for DCC unless I add sound. I can't understand why some hobbyists insist on this antiquated 3 rail power system with out of scale wheels, etc. Not proper Model Railroads/Railways at all....I abandoned my Hornby No.O Tinplate Clockwork set back in the Fifties ( rust and dust).

Moved on to HO, Sn42, andnow On42.

Doc AV    Down under. Plop

 

 

Because we find it fun.  Sorry you gave up on something you once thought was fun.  I did that with scale modeling though 

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