Dual-Gauge Track: 45mm and 16.5mm

BakerJohn

BakerJohn

Baker, Modeler, future husband
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Has anyone tried this sort of thing? I just did a quick SketchUp drawing for what I'm thinking. Ultimately, I want to the LHRR to have its 'full size' engines (running on 45mm track) and its own 1/4 scale engines (my HO stock running on 16.5mm track). My biggest problem I'm coming up with so far is that the flangeway for the 45mm through the HO rails would be way to big for HO trains to be able to safely cross the gap.

Below: my drawing with the flangeway gap (5mm gap) which results in a rail gap of about 25mm for the HO trains to (attemp to) cross. Screenshot 2025-02-10 16.45.33.png

Below: No gap for the 45mm track, just to show my drawing.
Screenshot 2025-02-10 16.45.49.png

Any thoughts, suggestions are appreciated! Thanks!
 
Gap the 45mm rails, and mount the 16.5mm on a foam underlay, thick enough for the heavier loco's and stock to push the 16.5mm rail down..
I think you would have to limit the crossing speed of the 45mm consists?

Or perhaps arrange for the narrow gauge trackbed to be 'lowered' in some way?

PhilP.
 
BakerJohn said:
Has anyone tried this sort of thing? I just did a quick SketchUp drawing for what I'm thinking. Ultimately, I want to the LHRR to have its 'full size' engines (running on 45mm track) and its own 1/4 scale engines (my HO stock running on 16.5mm track). My biggest problem I'm coming up with so far is that the flangeway for the 45mm through the HO rails would be way to big for HO trains to be able to safely cross the gap.

Below: my drawing with the flangeway gap (5mm gap) which results in a rail gap of about 25mm for the HO trains to (attemp to) cross. View attachment 338765

Below: No gap for the 45mm track, just to show my drawing.
View attachment 338766

Any thoughts, suggestions are appreciated! Thanks!
Click to expand...
Wow John, that is a very ambitious project that you are considering.
 
PhilP said:
Gap the 45mm rails, and mount the 16.5mm on a foam underlay, thick enough for the heavier loco's and stock to push the 16.5mm rail down..
I think you would have to limit the crossing speed of the 45mm consists?

Or perhaps arrange for the narrow gauge trackbed to be 'lowered' in some way?

PhilP.
Click to expand...
I think PhilP PhilP might be onto something: could you lay the 16.5mm rails straight onto the 45mm sleepers? I'm assuming that you can get track chairs for OO gauge, much as you can for 45mm gauge...
That might lower the smaller rails enough for the 45mil flanges to clear. If you run deep-flanged stock in 45mm (I'm thinking LGB) then this might be a non-starter...similarly if you want trackwork any more complex than a parallel run, ie turnouts. Trial and error might be the way ahead on this, though an engineer would no doubt disagree! A good challenge for the grey matter, though! :clap:
 
My pal did this in Swindon many moons ago with 45/32/16.5 gauge. He just had a circuit with no points thus the 16.5 track could be laid straight out of the box onto the inside on the rails. I think there was a common rail for the 32/45 tracks. This was a long time ago now, last centuary!
 
Software Tools said:
The tricky part is going to be the difference in rail profile/height and flange depth at the crossings.... with mixed gauge track the same rail profile/height is usually used for both gaigues.

View attachment 338773
Click to expand...
Wow, where is that track work?

I see a loco in the distance but I couldn't identify it....
 
Mmm, flange depth on the 45mm vehicles will be the issue.

In order for the 16.5mm stock to run through where the rail is cut, then a base for the 16.5mm flanges would be necessary, but this would cause the 45mm stock to bounce up, especially if using LGB wheels.

Oh forget that rubbish - everybody else has already worked it out :banghead:
 
Rhinochugger said:
Mmm, flange depth on the 45mm vehicles will be the issue.

In order for the 16.5mm stock to run through where the rail is cut, then a base for the 16.5mm flanges would be necessary, but this would cause the 45mm stock to bounce up, especially if using LGB wheels.

Oh forget that rubbish - everybody else has already worked it out :banghead:
Click to expand...
That is spot on Rhino, if there are to be as in the first drawing divergencies in either points or just a change of side not using a point but requiring rail crossover the issue of a gap to allow larger gauge wheels through will be a big issue for the 16.5 gauge. I had considered a similar problem with running 45mm on the local miniature line with 5 and 7.5 inch mixed gauge points (the 45mm sits between the 2 and 3rd rail being ok for the smaller gauge). To get the 45 across the gaps a slot in riding rail would be required. Not sure that would be viable in the smaller scale as asked by BakerJohn BakerJohn .
 
The best way I reckon you could 'make it work' is by having the 16.5 mm track dive under the 45 mm track....
 
I think a big part of the problem here is the angle on the curve HO track. If the curve wasn't so steep, it'd be a smaller linear gap created by the large scale flangeway.

My first thought is to have pieces of HO rail swing in and out to open the flangeway for the 45mm stock. But, I do like PhilP PhilP idea of the HO track being able to be pushed down by the 45mm stock. I could see rolling stock being a problem though, as most of mine are quite light. Setting the HO track lower than the 45mm could work, except for when the HO needs to cross the 45mm rail. But, maybe a single "door" there would work, too.
Back to sketchup...
 
Gizzy said:
The best way I reckon you could 'make it work' is by having the 16.5 mm track dive under the 45 mm track....
Click to expand...
There was a video a few years ago, of a temporary crossing constructed over the top of an existing track to allow a loco to cross from a workshop to, I think, a heritage railway.

However, the big issue here is LGB flanges - it would be easier and maybe even possible with Accucraft Fn3 wheelsets and European HO wheelsets on the 16.5mm track. Even Bachmann Fn3 wheelsets have deeper flanges than the Accy ones.
 
I drew up a quick 90 degree crossing.
Screenshot 2025-02-11 08.32.37.png
Obviously, bare minimum flangeway for the 45mm would have to be 5mm. I think this MAY be possible, but smaller wheels will likely get stuck. I think I may just just up a piece of my HO track and see what happens...

Another thought: These crossings will likely see more HO activity than 45mm (it'd be inside, in a basement where the HO trains can just run roundy round all day). So, maybe I should build the crossings with HO being the focus and when a LS train comes through, I can modify the piece how I need to (ie. a section of rail that comes out manually to create the needed flangeway).


EDIT: Likewise, if I were to set the HO track lower than the 45mm, I could just have a piece of 45mm rail the is removable unless a LS train is passing through.
I drew this too... Track is clear for HO trains (25mm clearance on inside of curve, 21mm on outside).
Screenshot 2025-02-11 08.49.45.png

Track is in place (manually) for 45mm trains. All I'd have to do is cut a grove in the brass rail for the HO rail to fit into. Then, I'd be able to use SplitJaws or something similar to keep the piece of rail in place.
Screenshot 2025-02-11 08.49.36.png
 
Last edited:
Rhinochugger said:
There was a video a few years ago, of a temporary crossing constructed over the top of an existing track to allow a loco to cross from a workshop to, I think, a heritage railway.

However, the big issue here is LGB flanges - it would be easier and maybe even possible with Accucraft Fn3 wheelsets and European HO wheelsets on the 16.5mm track. Even Bachmann Fn3 wheelsets have deeper flanges than the Accy ones.
Click to expand...
Rhino, Is this what you're talking about? Imgur Video
 
BakerJohn said:
I drew up a quick 90 degree crossing.
View attachment 338782
Obviously, bare minimum flangeway for the 45mm would have to be 5mm. I think this MAY be possible, but smaller wheels will likely get stuck. I think I may just just up a piece of my HO track and see what happens...

Another thought: These crossings will likely see more HO activity than 45mm (it'd be inside, in a basement where the HO trains can just run roundy round all day). So, maybe I should build the crossings with HO being the focus and when a LS train comes through, I can modify the piece how I need to (ie. a section of rail that comes out manually to create the needed flangeway).


EDIT: Likewise, if I were to set the HO track lower than the 45mm, I could just have a piece of 45mm rail the is removable unless a LS train is passing through.
I drew this too... Track is clear for HO trains (25mm clearance on inside of curve, 21mm on outside).
View attachment 338785

Track is in place (manually) for 45mm trains. All I'd have to do is cut a grove in the brass rail for the HO rail to fit into. Then, I'd be able to use SplitJaws or something similar to keep the piece of rail in place.
View attachment 338786
Click to expand...
I think your last edit is feasible and the way to go.

I have a kit built diamond crossing from Bertram Heyn which used this notching method for the code 332 rails....
 
Will the HO be track-powered?

Perhaps, ALWAYS, use the same socket outlet for the HO and GScale power supplies..

That way, there is less chance of you shorting the HO controller, when you insert the other rails.

PhilP.
 
PhilP said:
Will the HO be track-powered?

Perhaps, ALWAYS, use the same socket outlet for the HO and GScale power supplies..

That way, there is less chance of you shorting the HO controller, when you insert the other rails.

PhilP.
Click to expand...
Hadn't considered that, Phil. Yes, my plan is to power the HO track. The 45mm won't be powered, but if it is metal it would short the line. Maybe I make a piece out of something else then. 3D printed piece, maybe? just to fit in that space when needed.
 
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