Prototypical Pointwork Radius

[Qweqwe]

Hi,

For steam locos, a “run around” was used to allow the loco to couple to the other end of the coaches. Does anyone know approximately what radius would be realistic for such pointwork? For example on a terminus station on a branch line with 0-6-0 tank engines, how sharp would the curves on the points be? Would Peco “large radius” points be fairly prototypical, or still too small of a radius to be truly accurate?

Edited May 10 by Qweqwe

[Hal Nail]

Still too sharp according to a previous thread. You may well find dimentions on one of the manufacturers of hand built track parts, as well as Templot.

 

 

Edited May 11 by Hal Nail

[Siberian Snooper]

I would use Peco medium radius turnouts, proper turnouts would be in the order of 1 in 7 or 8 B's, but I would use a 6B, due to space.

 

 

[Wheatley]

Prototype pointwork is specified in terms of switch length (A, B, C...) and the crossing angle (1 in 6, 1 in 8 ...) rather than radius. The Peco large radius is about 1 in 5, I've no idea where to measure the switch length from though. So A6, B8 etc. 

 

I've laid out a double to single  junction on my layout using entirely Peco large radius points, it's roughly half the length the prototype plan says it should be which gives you an idea how compromised Peco points are. That said it looks good and it effectively self-compressed itself to fit the space available without me having to do anything complicated !

[Jeremy Cumberland]

1 hour ago, Wheatley said:

The Peco large radius is about 1 in 5, I've no idea where to measure the switch length from though. So A6, B8 etc.

The crossings are more like 1 in 7.5. Your 1 in 5 comes from the 12 degree diverging angle, caused by the diverging line continuing to curve beyond the crossing. Peco's "frog angle" is misleading.

 

The effective switch length (using the length of the turnout and radius as a guide, rather than the actual length of Peco switches) is something a little shorter than an A.

 

Peco large radius turnouts are tighter than the B7 points you might expect to find in such a situation (approx 1780 mm radius in 4 mm scale), but at 1524 mm radius they aren't far out. Radius isn't everything, though, and given the excessive flangeway widths and switch clearances found in Peco points, to cope with older, coarser, wheel standards, I think I might agree with @Siberian Snooper and opt for Peco medium radius instead, as having a better overall look. Where large radius points really make a difference is when you are moving whole trains across them rather than engines on their own, where the larger radius makes for smaller end play between the vehicles.

Edited May 11 by Jeremy Cumberland

[Qweqwe]

Thanks for the informative replies. Seems like existing options from track manufacturers are still a compromise in terms of realism. So if money and space were no object, the way to get 100% prototypical points would be through kits/scratch building?

[bécasse]

1 hour ago, Qweqwe said:

Thanks for the informative replies. Seems like existing options from track manufacturers are still a compromise in terms of realism. So if money and space were no object, the way to get 100% prototypical points would be through kits/scratch building?

....... and necessarily using P4 rather than OO or EM. Using a scale where the track gauge is less than that of the scaled down prototype inevitably requires compromises to track work geometry. For example, in OO a point of the same scaled-down "radius" as the prototype will inevitably actually be over 12% shorter simply because of the use of a narrower than scale track gauge.

[Izzy]

1 hour ago, Qweqwe said:

Thanks for the informative replies. Seems like existing options from track manufacturers are still a compromise in terms of realism. So if money and space were no object, the way to get 100% prototypical points would be through kits/scratch building?

Yes, and probably space more than money. But realism is subjective. A lot of smaller stations would occupy a great deal of space yet could end up being boring both to look at and operate. Some selective compression is often quite helpful, but of course discussions like this have been down this road a great many times down the decades. At the end of the day space is what most people struggle with in combination with other factors and why scaled down radii and such like are common in modelling simply because it’s the best compromise for the majority.

 

Bob

[Bittern]

Because of the constraints imposed by the 12° angle and wider-than-scale double track spacing, handbuilt/kit trackwork can sometimes fit larger radii into a comparable length (ISTR a fairly long post by Martin on that point, either here or on Templot Club), especially when you have more complex formations. You'll probably still want to shrink radii, but perhaps less than you otherwise would need to.
 

 

[Qweqwe]

11 hours ago, Izzy said:

Yes, and probably space more than money. But realism is subjective. A lot of smaller stations would occupy a great deal of space yet could end up being boring both to look at and operate. Some selective compression is often quite helpful, but of course discussions like this have been down this road a great many times down the decades. At the end of the day space is what most people struggle with in combination with other factors and why scaled down radii and such like are common in modelling simply because it’s the best compromise for the majority.

 

Bob

This is a fair point I forgot to consider! The thing that got me thinking about this topic was the fact that I’ve just bought a house with a double garage and lots of room but I I’m interested in modelling just a small branch line terminus station. Not more than a runaround and maybe a single siding. Which got me thinking with all this space maybe I could consider doing fairly prototypical track work geometry. But anyway my skill level isn’t high enough for scratch building track just yet so Peco large radius will do just fine. But I was still curious about that would be considered most realistic

[Izzy]

8 hours ago, Qweqwe said:

This is a fair point I forgot to consider! The thing that got me thinking about this topic was the fact that I’ve just bought a house with a double garage and lots of room but I I’m interested in modelling just a small branch line terminus station. Not more than a runaround and maybe a single siding. Which got me thinking with all this space maybe I could consider doing fairly prototypical track work geometry. But anyway my skill level isn’t high enough for scratch building track just yet so Peco large radius will do just fine. But I was still curious about that would be considered most realistic

That’s a nice lot of space. If it’s just (!) going to be a small and simple terminus to get you going so to speak could you perhaps consider using the British Finescale points and trackwork? I presume we are considering 4mm here. They do an ever expanding range and whilst not cheap all you have to do is slide the rail into the track base. Well there is very slightly more to it but not much, and the pointwork is to prototype diemensions. So B6, B7, and so on. Something to think about anyway.
 

Bob

[Qweqwe]

That’s something I might have a look at later on, for the time being I have a few Peco large radius points and flex track lying around so I’ll be using that. But I’ll definitely have a look at your suggestions. Thanks!

[hayfield]

9 hours ago, Qweqwe said:

This is a fair point I forgot to consider! The thing that got me thinking about this topic was the fact that I’ve just bought a house with a double garage and lots of room but I I’m interested in modelling just a small branch line terminus station. Not more than a runaround and maybe a single siding. Which got me thinking with all this space maybe I could consider doing fairly prototypical track work geometry. But anyway my skill level isn’t high enough for scratch building track just yet so Peco large radius will do just fine. But I was still curious about that would be considered most realistic

 

 

Not quite true as far as cost,

 

Wanting something more prototypical certainly rules out most (cheap) ready to run turnouts due to size and design, both of which do not comply with the original requirements

 

This leaves you with either buying expensive finescale RTR products/ potentially changing gauge/building your own

 

Taking the latter building your own, British Finescale produce a range of easy to build and competitively price (£30 appx) products in 4 mm scale in 3 gauges

 

The new kid on the block and in development is Templot plug track, The cost of a turnout base and chairs is under £1 and rail would cost £2 to £3

First of all the system is very easy to build

Probably more detailed and prototypical than anything else on the market

Cheap and reusable filing jigs available 

Not for everyone but in a couple of years may well be far more mainstream for finescale modellers

[34theletterbetweenB&D]

On 13/05/2024 at 10:26, Izzy said:

... realism is subjective. A lot of smaller stations would occupy a great deal of space yet could end up being boring both to look at and operate. Some selective compression is often quite helpful, but of course discussions like this have been down this road a great many times down the decades...

I am in complete agreement with the above, but would add the 'artistic vision' element and the layout builder's interests and capability.

 

Every now and again a layout appears which is chronically boring and sprawling due to realistic but operationally  limited track layout: but is actually positively enchanting in operation because those that constructed it composed a scene that was attractive and so interesting, that the 'defect' of the track layout is simply not noticed.

 

This is where the potential layout constructor has to 'know thyself'. 

[martin_wynne]

On 13/05/2024 at 10:26, Izzy said:

A lot of smaller stations would occupy a great deal of space yet could end up being boring both to look at and operate.

 

This may be true for terminal branch lines.

 

But a through station on a lightly-used secondary route is very different. It might be double-track, or a passing loop on single track. But the real activity arrives when you imagine that it is part of a diversionary route while the main line is blocked for engineering work.

 

Here for example is Rubery on the Halesowen Railway:

 

 http://www.photobydjnorton.com/HalesowenLineEnthusiast.html

 

(The above web site does not have a security certificate, so some browsers may refuse to link it.)

 

Martin.

 

[johnofwessex]

4 hours ago, martin_wynne said:

 

This may be true for terminal branch lines.

 

But a through station on a lightly-used secondary route is very different. It might be double-track, or a passing loop on single track. But the real activity arrives when you imagine that it is part of a diversionary route while the main line is blocked for engineering work.

 

Here for example is Rubery on the Halesowen Railway:

 

 http://www.photobydjnorton.com/HalesowenLineEnthusiast.html

 

(The above web site does not have a security certificate, so some browsers may refuse to link it.)

 

Martin.

 

 

Mid Hants?

[Harlequin]

@Qweqwe When you design your layout it's best to think about all the elements in combination. The trackwork, the landscape, the era, the region, the signalling, operations, the level of compression, real vs. fiction, how the rest of the world will be represented, etc, etc... They all feed into each other and the radius of your existing turnouts is just one tiny part of that picture that may or may not fit in a fully worked out design.

 

Edited May 14 by Harlequin

[Siberian Snooper]

12 hours ago, martin_wynne said:

 

This may be true for terminal branch lines.

 

But a through station on a lightly-used secondary route is very different. It might be double-track, or a passing loop on single track. But the real activity arrives when you imagine that it is part of a diversionary route while the main line is blocked for engineering work.

 

Here for example is Rubery on the Halesowen Railway:

 

 http://www.photobydjnorton.com/HalesowenLineEnthusiast.html

 

(The above web site does not have a security certificate, so some browsers may refuse to link it.)

 

Martin.

 

 

Teign Valley, a diversionary route for the seawall. Moguls on the Cornish Riviera.

 

 

 

 

[roythebus1]

I have to agree with Hayfield and others about. the finetrax kits, they are just superb. I've been handbuilding track since I was at school in the 1960s when pcb was just about available. I've tried the C&L track components and they are reasonably easy to use. with the advent of Templot that changed things as to how to plan and build a layout.

when the Finetrax kits came along I waited a while before taking the plunge. My home layout has a ladder of slips, includin one double which I could never get to run properly.  I bought a Finetrax double slip as a starter, thinking if I can build this I can build anything. It took a couple of evenings, it fitted perfectly where my hand-made slip was, one of the benefits of using Templot, it was installed and works perfectly.

 

I'd suggest the OP get one of the kits and ditches the idea of Peco points, you won't regret it and you'll save time in wanting to change it later. Those kits really are that easy.

 

 

[hayfield]

On 10/05/2024 at 22:30, Qweqwe said:

Hi,

For steam locos, a “run around” was used to allow the loco to couple to the other end of the coaches. Does anyone know approximately what radius would be realistic for such pointwork? For example on a terminus station on a branch line with 0-6-0 tank engines, how sharp would the curves on the points be? Would Peco “large radius” points be fairly prototypical, or still too small of a radius to be truly accurate?

 

On 13/05/2024 at 08:26, Qweqwe said:

Thanks for the informative replies. Seems like existing options from track manufacturers are still a compromise in terms of realism. So if money and space were no object, the way to get 100% prototypical points would be through kits/scratch building?

 

On 13/05/2024 at 23:30, Qweqwe said:

This is a fair point I forgot to consider! The thing that got me thinking about this topic was the fact that I’ve just bought a house with a double garage and lots of room but I I’m interested in modelling just a small branch line terminus station. Not more than a runaround and maybe a single siding. Which got me thinking with all this space maybe I could consider doing fairly prototypical track work geometry. But anyway my skill level isn’t high enough for scratch building track just yet so Peco large radius will do just fine. But I was still curious about that would be considered most realistic

 

On 14/05/2024 at 08:57, Qweqwe said:

That’s something I might have a look at later on, for the time being I have a few Peco large radius points and flex track lying around so I’ll be using that. But I’ll definitely have a look at your suggestions. Thanks!

 

7 hours ago, roythebus1 said:

I have to agree with Hayfield and others about. the finetrax kits, they are just superb. I've been handbuilding track since I was at school in the 1960s when pcb was just about available. I've tried the C&L track components and they are reasonably easy to use. with the advent of Templot that changed things as to how to plan and build a layout.

when the Finetrax kits came along I waited a while before taking the plunge. My home layout has a ladder of slips, includin one double which I could never get to run properly.  I bought a Finetrax double slip as a starter, thinking if I can build this I can build anything. It took a couple of evenings, it fitted perfectly where my hand-made slip was, one of the benefits of using Templot, it was installed and works perfectly.

 

I'd suggest the OP get one of the kits and ditches the idea of Peco points, you won't regret it and you'll save time in wanting to change it later. Those kits really are that easy.

 

 

 

I think you really should write down what you want to model if you require something prototypical before you actually do anything

 

What era do you want to model then what region/location. You have said space is no issue as you wish to model a branch line station

 

With the exception of their finescale bullhead track, Peco standard track is H0 not 00 and flatbottom so you are starting off with both the wrong scale and probably the wrong era unless you wish to model Modern image to 3.5mm scale, disregarding the geometry of Peco track.

 

In my opinion the smaller the layout the more the trackwork stands out, modelling is usually a compromise, when its not do make the most of it

 

However you could with Peco track quickly and cheaply try out track formations, a small simple branch station may not offer the operating potential you require over the long term. Perhaps buy one of those books which shows the track plans of various stations. try and replicate then and see if they allow the operating opportunities you require. Then once you have settled on a plan then think of how you can make a model which looks prototypical 

[Siberian Snooper]

If you have a particular prototype station in mind , have a look at the map on the NLS website. Here's the link to the 25 inch maps for England and Wales.

 

https://maps.nls.uk/os/25inch-england-and-wales/

 

These maps can be imported into Templot at the correct scale, so that you can add the Tempolot templates over the top.