'Pizza' G scale 'layout'

Rowan Bravington · 14 Dec 2017

I was looking in my video camera for a video of the monorail in Ireland from our recent visit there, and found this ............ may be of interest to our members.

It took 30 minutes to upload to You Tube........... surely there is a faster way, or aren't I pedalling fast enough?

Rowan Bravington · 14 Dec 2017

And here it is with Ivor painted.

dunnyrail · 14 Dec 2017

M piza

Mattawa · 14 Dec 2017

Great little big pizza !

Thanks for the videos. What's the radius of this very very tight curve ? How did you make the track ? Thanks for your answers.

dunnyrail · 14 Dec 2017

Yes Track Radius of perhaps the outside curve and a pic of the chassis naked as well would be very interesting as it appears to be of staggered construction.

Zerogee · 14 Dec 2017

dunnyrail said:
Yes Track Radius of perhaps the outside curve and a pic of the chassis naked as well would be very interesting as it appears to be of staggered construction.

Great bit of modelling, and I love the "curved" loco!
Unless there is some sort of differential incorporated into the gearbox, do you have any problems with the wheels on each axle turning at the same speed, but the outer wheels having to travel much further than the inner ones on every lap?
Not something that we normally have to think about, although to some much smaller extent it must also affect R1 operations....?

Jon.

dunnyrail · 14 Dec 2017

Zerogee said:
Great bit of modelling, and I love the "curved" loco!
Unless there is some sort of differential incorporated into the gearbox, do you have any problems with the wheels on each axle turning at the same speed, but the outer wheels having to travel much further than the inner ones on every lap?
Not something that we normally have to think about, although to some much smaller extent it must also affect R1 operations....?

Jon.

I think the chassis is unusual with the wheels like this so that the effect of that would be reduced. Am I correct?

Zerogee · 14 Dec 2017

dunnyrail said:
I think the chassis is unusual with the wheels like this so that the effect of that would be reduced. Am I correct?
View attachment 230993

That reduces any flange alignment problem, JonD, but not the speed differential.... if you think about it, both inner and outer wheel on a rigid axle are turning at the same speed, but the outer one has to cover significantly more distance than the inner one..... this is exactly why your car has a differential in the driven axle, so the wheels can turn at different speeds when cornering.
It probably doesn't matter that much in model terms, but the inner wheels will always be slipping against the rail. Just a thought, but if it runs OK (as it seems to from the vids) then it's obviously not a problem.

Jon.

Gavin Sowry · 14 Dec 2017

That is why the tread on railway wheels is tapered... bigger radius closer to the flange, smaller to the outer.
When going around a curve the wheel on the high leg is running with the flange close to the rail, on the low leg the wheel is/should be running with its outer edge (smaller diameter) on the rail, hence travelling a shorter distance. This is also why we have gauge widening, to allow relative sideways movement of the wheelset across the rail.

Rowan Bravington · 14 Dec 2017

Mattawa said:
Great little big pizza ! Thanks for the videos. What's the radius of this very very tight curve ? How did you make the track ? Thanks for your answers.

Thanks to all for the comments.
Track measurement is approx. 10.5 inches diameter to the outside rails.
I made the track using a one-rail manual rail bender - it was a bit of a challenge. I made it to fit on a display layout for the Caulfield Model Train Show here in Melbourne, Vic.
The base pictures should explain the mechanism - the plastic bit holding the motor is from a sliding curtain rod.

Both axles are 'fixed' and not offset in any way. Much trial and error went into the design - mostly error.

Zerogee · 14 Dec 2017

Looks like a very cunning bit of plastic engineering!

Jon.

trammayo · 15 Dec 2017

Zerogee said:
That reduces any flange alignment problem, JonD, but not the speed differential.... if you think about it, both inner and outer wheel on a rigid axle are turning at the same speed, but the outer one has to cover significantly more distance than the inner one..... this is exactly why your car has a differential in the driven axle, so the wheels can turn at different speeds when cornering.
It probably doesn't matter that much in model terms, but the inner wheels will always be slipping against the rail. Just a thought, but if it runs OK (as it seems to from the vids) then it's obviously not a problem.

Jon.

R1's DO play havoc with wheel treads - wearing the plating on the likes of the big haulers! I've had to convert tenders to pick up the current.

Rowan Bravington said:
Thanks to all for the comments.
Track measurement is approx. 10.5 inches diameter to the outside rails.
I made the track using a one-rail manual rail bender - it was a bit of a challenge. I made it to fit on a display layout for the Caulfield Model Train Show here in Melbourne, Vic.
The base pictures should explain the mechanism - the plastic bit holding the motor is from a sliding curtain rod.

View attachment 230995
Both axles are 'fixed' and not offset in any way. Much trial and error went into the design - mostly error.
View attachment 230996

Absolutely marvellous - and great lateral (or radial) thinking. We only have a tiny tree at Christmas (non-organic) it sits on the cuboard top - out of the way of our two amateur lumberjacks (overactive cats). Now you've brillianty demonstrated how I could have a G Scale train running around the tree! I probably won't go there as I'm running out of paper for my "to do" list - but it is great food for thought!

dunnyrail · 15 Dec 2017

Gavin Sowry said:
That is why the tread on railway wheels is tapered... bigger radius closer to the flange, smaller to the outer.
When going around a curve the wheel on the high leg is running with the flange close to the rail, on the low leg the wheel is/should be running with its outer edge (smaller diameter) on the rail, hence travelling a shorter distance. This is also why we have gauge widening, to allow relative sideways movement of the wheelset across the rail.

Understanding the logic of what you say Gavin I think the best way may have been to use a Ballbearing Wheel Axle. Looking at the construction that Rowan has shown us with only a single wheel drive that would have been an option. An LGB Ball Bearing Axle would also help with the pickup having Tabs for this purpose.

Mattawa · 15 Dec 2017

Nice work. No wagon or coach in sight ?

stockers · 15 Dec 2017

Going back to wheel differential, the flange squeal that we are all familiar with on the big railway is often not actually the flange but one wheel catching up with the other by slipping the tread on the rail.

Rowan Bravington · 15 Dec 2017

Mattawa said:
Nice work. No wagon or coach in sight ?

Not at this stage... it might just around the corner !

trammayo · 16 Dec 2017

Rowan Bravington said:
Not at this stage... it might just around the corner !

They might take some finding as there are 360 corners!

Rowan Bravington · 16 Dec 2017

trammayo said:
They might take some finding as there are 360 corners!

And, I've just discovered I am unable to locate the motorized unit... it may have started to play up and with my short - well, attention span - it may have got the big A !!

Ivor still exists however.

So there may be light at the end of the tunnel. And I may need to make another. And, if so, the track may appear on next years Caulfield Train Show layout.

ColinK · 12 Jan 2018

Its almost prototypical. While over in Germany in December we briefly visited Halberstadt. There was a Christmas Market on which included a train going round a tight circle of track. So add a couple of coaches full of children and so Christmas lights and you’ve got it.

Rowan Bravington · 15 Jan 2018

ColinK said:
Its almost prototypical. While over in Germany in December we briefly visited Halberstadt. There was a Christmas Market on which included a train going round a tight circle of track. So add a couple of coaches full of children and so Christmas lights and you’ve got it.

Sounds like a good idea. Will have find a small tree to place inside the tracks.

'Pizza' G scale 'layout'

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