Sheffield Exchange, Toy trains, music and fun!

[Peter Eaton]

8 hours ago, Northmoor said:

Those are some of the best transition curves I have ever seen on a OO layout.

 

Out of keen interest !

Is there a formula or spec for producing railway transition curves ? ie a 90 degree curve.

Obviously this takes the model railway layout above the set track level,

 

thanks

Peter

[Gibbo675]

45 minutes ago, Peter Eaton said:

 

Out of keen interest !

Is there a formula or spec for producing railway transition curves ? ie a 90 degree curve.

Obviously this takes the model railway layout above the set track level,

 

thanks

Peter

Hi Peter,

 

Transition curves may be plotted using differential calculus, on the railway they are measured by taking the versines of overlapping arcs taken from such calculated data. The P-Way engineers have tables of versines to easily convert to find the particular radius at any given point on the curve.

 

https://en.wikipedia.org/wiki/Hallade_method

 

The Euler spiral is regarded as one of the smoothest ways to transition from linear to circular path and would be the ideal plot.

 

The speed of the train trough any given curve will be determined by the radius of the curve and also the elevation that may be applied to that curve.

 

Hope you like doing sums !!!

 

Gibbo.

[Andrew P]

7 hours ago, Dagworth said:

Thank you, lots more of the layout here at RMweb members day at Ricoh in September 2014 and there is a thread about the layout here rather than detail Clive’s layout thread  

 

Andi

I WOZ THERE, Not on your Video, but my mates took me there and it was my first day out after my Stroke, a very enjoyable day, and a superb Layout Andi.

[St Enodoc]

6 minutes ago, Gibbo675 said:

Hi Peter,

 

Transition curves may be plotted using differential calculus, on the railway they are measured by taking the versines of overlapping arcs taken from such calculated data. The P-Way engineers have tables of versines to easily convert to find the particular radius at any given point on the curve.

 

https://en.wikipedia.org/wiki/Hallade_method

 

The Euler spiral is regarded as one of the smoothest ways to transition from linear to circular path and would be the ideal plot.

 

The speed of the train trough any given curve will be determined by the radius of the curve and also the elevation that may be applied to that curve.

 

Hope you like doing sums !!!

 

Gibbo.

There are much easier ways. The Scalefour Digest describes one such but it's copyright, so I can't reproduce it here. I've described how I use that method here:

 

 

 

 

 

[Enterprisingwestern]

 

Just do a Fibonacci spiral, sorted!

 

Mike.

[Dr Gerbil-Fritters]

44 minutes ago, Enterprisingwestern said:

 

Just do a Fibonacci spiral, sorted!

 

Mike.

 

Too lumpy for smooth train running

[Clive Mortimore]

2 hours ago, Peter Eaton said:

 

Out of keen interest !

Is there a formula or spec for producing railway transition curves ? ie a 90 degree curve.

Obviously this takes the model railway layout above the set track level,

 

thanks

Peter

There is always the Mortimore method, guess. 

 

Hence all my curves are not transitional but I model 00. 

[Clive Mortimore]

11 hours ago, Clive Mortimore said:

If you were to know Taigatrommel he is properly very proud to have thought of it.

 

8 hours ago, Dagworth said:

Thank you, lots more of the layout here at RMweb members day at Ricoh in September 2014 and there is a thread about the layout here rather than detail Clive’s layout thread  

 

Andi

 

There is a brief cammo appearance of Taigatrommel at about 3 minutes.

[Dr Gerbil-Fritters]

4 minutes ago, Clive Mortimore said:

There is a brief cammo appearance of Taigatrommel at about 3 minutes.

 

One of the most disturbing things I've ever seen on youtube...

 

that and all the sparklers are operating pans down of course

Edited August 14, 2020 by Dr Gerbil-Fritters

[Anadin Dogwalker]

Ravensclyffe- this is awesome ! Best looking Mk1 catenary ever.  I don't remember ever seeing it on the exhibition circuit- is it still around?

 

[Dagworth]

5 minutes ago, Anadin Dogwalker said:

Ravensclyffe- this is awesome ! Best looking Mk1 catenary ever.  I don't remember ever seeing it on the exhibition circuit- is it still around?

 

Very much so, it's only ever been shown as a work in progress as it is still under construction. 

 

Andi

[Clive Mortimore]

Less of that rowdy punk rock, 

 

 

[John Tomlinson]

3 hours ago, Clive Mortimore said:

There is always the Mortimore method, guess. 

 

Hence all my curves are not transitional but I model 00. 

I'm sure I'd seen that video before, but seeing it again I was struck by how good "OO" track can look when it's carefully laid and nicely ballasted.

 

As someone else said, the Overhead is very convincing too.

 

John.

[Peter Eaton]

8 hours ago, Gibbo675 said:

Hope you like doing sums !!!

 

Gibbo.

 

7 hours ago, Clive Mortimore said:

There is always the Mortimore method, guess. 

Thanks Gentlemen.

Hoping someone  saying ''Templot '' would help ?

only bit understanding is running into the respectable 3 foot curve.

will have to scratch my head more.

my A level result this week was not respectable in current maths.

was though in 1972.

An ex Railway draughtsman I should be able to plot a curve.

Peter

[5BarVT]

7 minutes ago, Peter Eaton said:

Hoping someone  saying ''Templot '' would help ?

If you don’t want to go to Templot, XtrackCAD does transitions too.  Takes a bit of time to get into the programme but there’s plenty of tutorials and the help function is quite good.

It’s free too!

Then you can print out and lat track over the top.  Worked well for me last time and I’m using it this time too.

Paul.

[Gibbo675]

5 minutes ago, Peter Eaton said:

 

Thanks Gentlemen.

Hoping someone  saying ''Templot '' would help ?

only bit understanding is running into the respectable 3 foot curve.

will have to scratch my head more.

my A level result this week was not respectable in current maths.

was though in 1972.

An ex Railway draughtsman I should be able to plot a curve.

Peter

Hi Peter,

 

Templot ?!?!

 

Trammel:

 

 

Or string and loci:

 

 

 

Batteries not included.

 

Gibbo.

[Clive Mortimore]

10 minutes ago, Peter Eaton said:

 

Thanks Gentlemen.

Hoping someone  saying ''Templot '' would help ?

only bit understanding is running into the respectable 3 foot curve.

will have to scratch my head more.

my A level result this week was not respectable in current maths.

was though in 1972.

An ex Railway draughtsman I should be able to plot a curve.

Peter

Hi Peter

 

Templot does help with transitional curves. It is not a system I use now but have in the past. I cannot remember fully but if you check Martin Wynne's Templot forum  I am sure there will be a tutorial on how to do so.

 

A very friendly word of warning, this thread was started by lazy pillock (well that is what Mrs M called me earlier today) so don't always expect a sensible answer form me.

 

 

[Gibbo675]

Hi Folks,

 

The tightest mainline railway curve in Britain is that of the 17 chain curve at Morpeth on the ECML, in 4mm scale 17 chains works out at 176.69" (14' 9") a considerably greater radius than most toy train sets.

 

The curve at Morpeth has a maximum speed of 50 mph which means that 4mm toy trains would need to be travelling at a maximum of 11.54" per second.

 

To give an idea of size a figure of eight track layout that scales to the curve at Morpeth would pretty much fill a tennis court with the added bonus that you would have to run your trains very slowly.

 

Most railway vehicles will traverse 5 chain curves but only very slowly, 5 chains works out at 51.96" (4' 4").

 

I do wonder if I have just "out-pedanted" the P4 types with such as the above ?

 

Gibbo.

[simontaylor484]

The repetitive maths can also be taken care of using Excel spreadsheets used it my self when doing surveying

 

Ooh Gibbo you are a pedant 

Edited August 14, 2020 by simontaylor484

[Enterprisingwestern]

 

Just to chuck the cat amongst the pigeons, as long as the curve isn't of SetTrack proportions, then with flexible track a little easement going into the curve should suffice in our scale, whether it's actually mathematically correct isn't of any great concern.

 

Mike.

[Gibbo675]

20 minutes ago, simontaylor484 said:

The repetitive maths can also be taken care of using Excel spreadsheets used it my self when doing surveying

 

Ooh Gibbo you are a pedant 

My dear Simon,

 

I think you will find that I am either, absolutely, completely, and utterly around the bend, or, as by way of my own preferred, representative perception of reality, somewhat ahead of the curve !

 

Gibbo.

[Dagworth]

The curves that were shown in the video that I posted were laid by mk1 eyeball with no calculations to get them exact, the only calculations used on the layout were the gradients. There’s also very little visible straight track as I am hopeless at laying it. Everything has a very gentle curve (and a reverse curve through the closed station to really get that APT to tilt)

 

Andi

[Satan's Goldfish]

On 12/08/2020 at 23:55, Clive Mortimore said:

It wasn't my joke. Mr Dagworth done the same thing on a recent operating session, placed a Bell container on the last freightliner wagon.

 

Couple of days late, but was rude not to have a Bell end when we'd take WL out. Even had a pot of paint labelled 'Bell End Purple' from when a 30ft Bulktainer was painted up

[Flying Fox 34F]

12 hours ago, Dagworth said:

The curves that were shown in the video that I posted were laid by mk1 eyeball with no calculations to get them exact, the only calculations used on the layout were the gradients. There’s also very little visible straight track as I am hopeless at laying it. Everything has a very gentle curve (and a reverse curve through the closed station to really get that APT to tilt)

 

Andi

It just goes to show, the Mk1 eyeball is the best device for track laying.  If it looks wrong it is wrong! 
 

Paul

[simontaylor484]

I remember when Wakefield railport  opened all you  would see were Bell  containers