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simon b

Hornby 4th radius curves with larger coaches

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Hi all, does anyone have pics of mk1 coaches on Hornby 4th radius curves? I just wanted to see how much of an overhang a rake of standard length coaches has on a oval of track.

 

I want to build an 8x4 "trainset" type of layout for my father to play trains on, using sectional track. But was concerned that the curves might look a little too sharp for what I have planned. 

 

Thanks in advance.

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Hi,

4th radius curves forming an oval will probably not realistically fit on an 8*4, I'm afraid. The track would be right up against the edges of the board.

 

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Ah, I could bring the board out a little further to compensate for that. Either that or I'll have to lay it in flexitrack but I was hoping to use sectional track for speed, it just needs to be pinned down and operating for the moment. 

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Posted (edited)
On 19/06/2020 at 17:43, Harlequin said:

Hi,

4th radius curves forming an oval will probably not realistically fit on an 8*4, I'm afraid. The track would be right up against the edges of the board.

 

I run them on one end of a 6x4 currently and they work perfectly well. Its tight - you have 20mm breathing space - but it provides a somewhat more graceful run.  It drops to a R3 at the other end and you can get small buildings, line side things in if you want.  You'll probably want to add scenic interest in the middle.

Edited by Shanghai Diver
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To answer the actual question - Hornby Mk 1s on 3rd and 4th radius settrack ....

 

1133655929_IMG_0486(2).JPG.fc7397b956de25fa0a51918474251a2c.JPG

 

Best of luck!

 

Chris

 

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On 19/06/2020 at 10:20, simon b said:

Hi all, does anyone have pics of mk1 coaches on Hornby 4th radius curves? I just wanted to see how much of an overhang a rake of standard length coaches has on a oval of track.

 

I want to build an 8x4 "trainset" type of layout for my father to play trains on, using sectional track. But was concerned that the curves might look a little too sharp for what I have planned. 

 

Thanks in advance.

I guess it's a trade-off.

If you want the convenience of setrack,

you have to accept it'll be less realistic.

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1 hour ago, Chimer said:

To answer the actual question - Hornby Mk 1s on 3rd and 4th radius settrack ....

 

1133655929_IMG_0486(2).JPG.fc7397b956de25fa0a51918474251a2c.JPG

 

Best of luck!

 

Chris

 

Thanks Chris, that's exactly what I was after. 

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On 19/06/2020 at 10:43, Harlequin said:

Hi,

4th radius curves forming an oval will probably not realistically fit on an 8*4, I'm afraid. The track would be right up against the edges of the board.

 

 

Hmmm - I just picked up two 4th radius curves the other day to see what they might look like in terms of coach overhangs - I've not had chance to try yet, but from the photos here I think maybe I need to use a larger radius! So this thread has answered that first question for me!

 

Phil - what radius (feet/inches or mm) would you say is the minimum for a "realistic" look?

 

Steve S

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Posted (edited)

I meant realistic in terms of practicality. If you have tracks close to the edge there's no room for any trackwork outside, very little room for scenery and more chance of rolling stock being knocked and damaged.

 

Visually realistic curves are a subjective thing and you have to decide what attributes you don't like: big gaps between vehicles, overthrow at the ends, overhang in the middle, sharp angles between vehicles, etc.

 

I think Iain Rice said (in a book) that a good test for a realistic radius was if the outside rail was still hidden under the vehicle as it took the curve. (Note that you can't see the outside rail in the photo above because of parallax.)

 

For most of us minimum radii are much more about practicality than realism, unfortunately.

 

Edited by Harlequin
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A feature of trainset curves that's perhaps even more visually intrusive than the radius is the lack of a transition at the end which means trains hit the curve with a noticeable jolt.  Transition curves will consume a bit more length than a simple curve but they also need more width, which is a problem if the nominal curve radius already fills the available board.

 

My theoretical solution (which I stress I haven't seen used in practice) is to save some width by inserting a short section at a tighter radius in the middle of the curve where it is likely to be less noticeable, particularly if it coincides with a scenic break, and form a transition at the ends of the curve with flexitrack. 

 

So a 180° nominally 4th radius curve would have say 1 x 3rd radius double curve in the middle with 1 x 4th radius double curve each side of it and the final 22.5° at each end formed as a transition curve using flexitrack.  This is probably a longer transition then necessary, but avoids having to cut the setrack curves.  In this case I would fix the first few inches of the flexi firmly using a 24" radius Tracksetta and then allow the rest to form a transition naturally.   Note that a double track curve is still possible with a minimum 2nd radius, the inner line being 3rd/2nd radii.

 

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Posted (edited)
18 hours ago, Flying Pig said:

A feature of trainset curves that's perhaps even more visually intrusive than the radius is the lack of a transition at the end which means trains hit the curve with a noticeable jolt.  Transition curves will consume a bit more length than a simple curve but they also need more width, which is a problem if the nominal curve radius already fills the available board.

 

My theoretical solution (which I stress I haven't seen used in practice) is to save some width by inserting a short section at a tighter radius in the middle of the curve where it is likely to be less noticeable, particularly if it coincides with a scenic break, and form a transition at the ends of the curve with flexitrack. 

 

So a 180° nominally 4th radius curve would have say 1 x 3rd radius double curve in the middle with 1 x 4th radius double curve each side of it and the final 22.5° at each end formed as a transition curve using flexitrack.  This is probably a longer transition then necessary, but avoids having to cut the setrack curves.  In this case I would fix the first few inches of the flexi firmly using a 24" radius Tracksetta and then allow the rest to form a transition naturally.   Note that a double track curve is still possible with a minimum 2nd radius, the inner line being 3rd/2nd radii.

 

 

I can help here:  I don't have a photo with a 4th radius curve, but I can illustrate the point: the first picture shows a 2nd and 3rd Radius Setrack curved end on a 4' wide board:

 

980497383_TransitionCurve3.jpg.170be714857b30a264c10d03b6c8be3e.jpg

 

There are no transition curves.  All track was spaced using Setrack spacing, so the siding on the far right would be where a 4th radius curve would start.  As noted by @Harlequin at the start of the thread, there's no space left for scenery or structures outside a 4th radius curve.

 

The second picture shows what happened when the track was relaid using a mixture of Streamline and Setrack, as @Flying Pig suggests:

 

1544642142_TransitionCurve1.jpg.fc109811c2005736b7d6d68affb2f324.jpg

 

For 45 degrees either side of the apex of the curve, it is still 2nd and 3rd Radius Setrack, but then eases into Streamline Transition curves.  On the right, the wider curve goes to the edge of the baseboard (like a 4th Radius curve would need to) but then curves back in to make room for a platform.

 

The layouts never progressed beyond bare track and are well gone now, but the end curves never gave any trouble - where derailments occurred they were almost always on the Setrack points (on the first layout).  Fortunately for me I stored the boards and kept the track as I'm now living in a house where I can use them again.  Hope this helps, Keith.

Edited by Keith Addenbrooke
(minor clarification)
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50 minutes ago, Keith Addenbrooke said:

The second picture shows what happened when the track was relaid using a mixture of Streamline and Setrack, as @Flying Pig suggests:

 

Your layout also shows how a streamline point can encroach onto the curve to claw back some of the length used up by the transition.  The overall effect looks very good indeed.

 

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Posted (edited)
14 hours ago, Flying Pig said:

 

Your layout also shows how a streamline point can encroach onto the curve to claw back some of the length used up by the transition.  The overall effect looks very good indeed.

 

 

Thank you.  Your kind comment prompted me to have a look to see if I had any old photos with trains on the curve, and I found this one, which I think I actually took on track-laying day itself. 

 

It does rather demonstrate how large the overhang gets, but do allow for the effect of parallax and the camera angle: both the first and second coaches in the train are on 2nd radius curves but they look very different here.
 

The key point is the gaps and angle between the coaches: but operating the layout from the side (not the outside end) meant the coaches were seen from the inside of the end curve, where they were being pushed closer together, so it wasn’t as obvious.

 

311705082_TransitionCurve4.jpg.69e0691ab9485783764214cdbb90677c.jpg

 

I no longer have this engine or rolling stock - the A4 Pacific was an excellent runner and the train would glide through the Streamline points with minimal throwover (Note: I only used medium points or larger).  As you've spotted, I also avoided an S-curve on the left side crossover by using a curved point. 

 

Based on my personal experience running trains, my conclusion would be that the end curves were something I had to live with - but I could do something about the transitions and points that made a noticeable difference.

Edited by Keith Addenbrooke
(minor edits) (2nd July: Key point paragraph had been missed, d’oh!)
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Posted (edited)

That's a good idea using a gentle curve to ease into a sharper one, not all the curve will be visible so that will help with what I have planned. Not having scenery on the outside of the curve wont be too much of an issue, as the visible curve will be in a cutting with a retaining wall both sides.

 

The majority of the setrack curves will be hidden to form a series of return and storage loops, only the ends will be seen. These then exit along the front of the board, and then use the full 4ft board width to gain access to the upper level. 

Edited by simon b
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You may have all you need now, and it sounds like some of your trackwork will be hidden, but a thought came to me this morning I'd not mentioned in my earlier posts that may be helpful to some.

 

This quick sketch illustrates:

 

1900343082_CurvedPoint1.jpg.0a121635aa5948d145477fe4056b1f5b.jpg

 

Taking a 4th Radius Curve as my start point, a transition into a 3rd Radius Curve instead saves on width, but adds length (here: 6").  Where that is not possible, continuing the curve into a point when it reaches the straight, as in the third suggestion, may help mask the sudden change visually - at least when there are no trains present.

 

Just a thought for where space is particularly tight.

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Alternatively, use the curve of the point for the last 12 degrees of the 90 ......

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Posted (edited)
4 hours ago, Chimer said:

Alternatively, use the curve of the point for the last 12 degrees of the 90 ......


Like this?  Assume there is a curve on the right hand side coming into the points from bottom to top.

 

Diagram pinched from my GW Branch Line thread but illustrates the suggestion.

 

8106C8F6-AD79-4B3C-9961-7D1B3FC4418F.jpeg.ce482e140cbf070fc64af96091717f53.jpeg

 

[Note - the purpose of this diagram was to compare the lengths of alternative Peco Streamline points - the angle of entry into the points from the right is not the same in 1 and 2].

 

 

 

Edited by Keith Addenbrooke

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Yes, that's what I had in mind ..... as you say, the inner leg of the curved point diverges 20.25 degrees against the 12 of all the straight points, the outer leg 9.

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Please excuse the crude MS paint drawing, but this is what I'm hoping to get on a 8x4. I've mocked it up with some of the track I have collected so far and it looks like it will fit, just.  Most of the curves are hidden except for the pair on the left side of the board rising from the lower to upper levels. It needs a couple of loco storage sidings adding at the terminus station, but i think it should have some operating potential.   

 

Any thoughts guys?

 

 

8 X 4 TRACK PLAN.png

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Very quick thoughts too late at night - if the gradient is not too steep, and the terminus throat and various junctions fit as you've sketched them, operationally that looks pretty good fun - max 3 coach trains probably?

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Posted (edited)

Whilst it may fit, in theory, are you sure about the double track reverse loop? As far as I can recall, even the master of the compressed main line roundy, CJF,  never squeezed one in. 

 

Speaking of CJF, his later 60 Plans for Small Locations contained an 8x4 incorporating most, if not all, the features you seem to be after (terminus, continuous run, justification for main line stock, tunnels and gradients) and offered space for 4 coach trains. He did note that baseboard construction would be rather involved, and it does feature a visible R1 curve on one of the station approach tracks but it packs in an awful lot. 

 

Edit: It's plan SP14, now that I've dug up my copy.

Edited by PatB

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Posted (edited)

The gradient is probably too steep, around 1 in 20 at best, because the station throat pointwork all needs to be level.

 

And that's assuming only 75mm between railtops which would make supporting the top level a challenge.

 

Edited by Harlequin

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Why don't you download AnyRail & sketch out your design with that? The free version limits the amount of track pieces you can use but it will prevent you from squeezing your curves too much, which is an easy mistake to make when drawing freehand...& you may just like it enough to buy the unlimited version.

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Well it sort of fits using second and third radius curves, but the crippler is only having at best 5 feet for the incline.  The double reversing loop is a no-no (I've left the diamond in but the inner loop can't connect).  And I don't think the think the third upper right loop is possible, even with first radius curves .......

 

163938125_simonjpg.jpg.a66812c8967ebd21f49f8a14689b0eec.jpg

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29 minutes ago, Chimer said:

Well it sort of fits using second and third radius curves, but the crippler is only having at best 5 feet for the incline.  The double reversing loop is a no-no (I've left the diamond in but the inner loop can't connect).  And I don't think the think the third upper right loop is possible, even with first radius curves .......

 

163938125_simonjpg.jpg.a66812c8967ebd21f49f8a14689b0eec.jpg

 

Thanks for setting that plan out, that helps me alot. The third upper loop I can do without, but I'd quite like to keep the double reverse loop. Do you think there is any way of moving the points for that onto the curve to gain more room?

 

The upper level looks ok to me, I wonder if it's possible to put the station throat on the incline aswell to lessen the climb?

 

Thanks.

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