Minimum Radius

[John Lewsey]

Hi ,what is the minimum radius you can have in P4 bearing in mind that there will be 0-8-0 engines.
John

[Will L]

Depends on the compromises you are prepared to make on the chassis. My LNER O2 goes round 3'6" no trouble.

We did have a discussion about gauge widening a while ago, and part of the upshot of this is information (a graph) about how tight a curve you can get a given length of fixed wheelbase round. It will answer your question but does get a bit technical.

[Tony Wilkins]

Hi John. I would say sensibly about 4 feet in old money or 1200mm.
It is possible to go a bit less, but the loco chassis needs to be designed to cope with that.
One also needs to consider the end throw if buffer locking is to be avoided, especially if it is a tank loco.
Regards
Tony.

[John Lewsey]

Thanks guys,so 4ft should be ok

[davebradwell]

Although I'm wary of encouraging tight radii, I should point out that 8cpld locos have very similar wheelbases to normal 0-6-0s with a WD coming in at 3" less than a J27 (or a 4F). A Q6 is a bit longer but only 2" more than a J39. Common problems with these sharp curves are wheels hitting front steps or bogies catching drain cocks. Tony mentions overhangs and my Q6s are on the mk2 tender coupling because I underestimated the effect - essentially the old rule of copying the prototype is best.

I get everything round a metre radius but it's best not to look. Pacifics certainly don't look comfortable. If you have space for 4ft rad then that would be a very good idea - I would place the reasonable minimum at around 3ft 6in but it may depend on regional differences. My WD tender was one of the biggest challenges, although the last big pacific tender was no trouble at all, despite minimal sideplay. Don't forget to test running tender first.

Don't forget to consider the offset on coaches and the number of wagons you might want to propel round curves.

All my curves are on Exacto widened bases, some flycut at an angle to get the cant. Len Newman was horrified.

DaveB

[Martin Wynne]

Hi ,what is the minimum radius you can have in P4 bearing in mind that there will be 0-8-0 engines. John

Hi John,

Aim for the Hastings radius as a practical minimum. 1066 mm (42").

Martin.

[bécasse]

It is also worth remembering that you can haul round a tighter radius curve than you can reliably propel round, particularly with anything more than a single vehicle.

[Hardwicke]

I have a 2ft radius and can get a 4F around it but only at walking pace. The real thing probably had to do the same.

[Tim V]

My retired layout had 3' radius curves, I ran 30 wagon trains and eight coupled engines round it easily.

Some of those wagons were re-wheeled r-t-r, just changed the wheels and couplings. Don't try propelling over those curves.

However, visiting engines/stock sometimes worked but often didn't. Lack of sideplay. Engines in particular had to be built for the tighter curves.

I was guided by an article by the MRSG in an old MRC showing the sideplay on a Castle class loco (GWR loco for those of lesser railways) on a 3' radius curve as 1mm. I thought I could build to those standards and yes I could.

[jim s-w]

Hi ,what is the minimum radius you can have in P4 bearing in mind that there will be 0-8-0 engines.
John

Do you mean absolute minimum something will run on or minimum that will look ok? Bear in mind that something like a 10ft radius curve scaled up would barely be big enough to not need a check rail and would have a 30mph restriction in it.

Personally I think once you get into the 6ft radius area it looks ok

[Julian Roberts]

I made a short test track 2ft radius curve simply to test what happens. Here 7 compensated wagons are propelled without any problem. AJ couplings. Looks terrible of course unless you're modelling some exciting industrial setting. Longer vehicles bufferlock on reverse curve. The 0-6-0 loco sideplay calculation was for 4ft radius, but that just shows my calculation was too conservative.

[youtube]WT07OjFIKic?si=HjVzfvQ_dBM3A9KM[/youtube]

This doesn't seem to work. This link will

https://youtu.be/WT07OjFIKic?si=HjVzfvQ_dBM3A9KM

[Will L]

This doesn't seem to work...

Does now, you only have to include the WT07OjFIKic bit from the full youtube url (https://www.youtube.com/watch?v=WT07OjFIKic) in the {youtube] command.

In case your wondering, the one you posted on your KYLE MPD thread recently which also didn't work had been posted in the Youtube smalls section which out forums [youtube] command does not seem able to cope with (webmaster?). I did try.

[grovenor-2685]

The problem comes if you use the Youtube "Share" button which gives a completely different URL.
The embedding works with the URL from the browser using just the bit after the v=.
Hovering over the youtube button gives you the syntax.

[Julian Roberts]

Thanks, Will and Keith

[Winander]

our forums [youtube] command does not seem able to cope with (webmaster?)

Our [youtube] code does work with Youtube shorts despite the 'shorts' directory in the path. Must be something clever Youtube is doing.

Julian made the same slip he did here by posting [youtube]_ba7agd_bqw?si=LBmC1k9impk_hIDh[/youtube]. The blue text is not required.

Code: Select all

[youtube]_ba7agd_bqw[/youtube] works.


[Will L]

our forums [youtube] command does not seem able to cope with (webmaster?)

Our [youtube] code does work with Youtube shorts despite the 'shorts' directory in the path. Must be something clever Youtube is doing.

Julian made the same slip he did here by posting [youtube]_ba7agd_bqw?si=LBmC1k9impk_hIDh[/youtube]. The blue text is not required.

Code: Select all

[youtube]_ba7agd_bqw[/youtube] works.


I was sure I'd tried that and got an error, hay ho.

[grovenor-2685]

Interesting, so the bit after the v= is replaced by the bit before the ? in the 'share' version.
Is there any way to add that info to the hover help on the button? Might be difficult to state clearly and briefly.

[Winander]

Is there any way to add that info to the hover help on the button? Might be difficult to state clearly and briefly.

I tried

[grovenor-2685]

Pretty good effort I'd say.

[Tony Wilkins]

It took me a while to get to grips with posting YouTube videos on the forum and I still have a fight with it sometimes. I didn't think you could post the video unless you chose to share them first. I usually find that I have to do that and then wait awhile before the desired link comes up. Don't know if this helps.
Regards
Tony.

[stephenfreeman]

[youtube] v=4d-kC2FE3xk&list=PL1UcIQskMxcTFakgZMfKiQFM_wibd_jVk&index=1[/youtube]

tried the syntax didn't work for me - not that it has anything to do with track but the full path does.

[youtube] https://www.youtube.com/watch?v=4d-kC2F ... Vk&index=1[/youtube]

[Martin Wynne]

[youtube] v=4d-kC2FE3xk&list=PL1UcIQskMxcTFakgZMfKiQFM_wibd_jVk&index=1[/youtube]
tried the syntax didn't work for me - not that it has anything to do with track but the full path does.
[youtube] https://www.youtube.com/watch?v=4d-kC2F ... Vk&index=1[/youtube]

Hi Stephen,

Enter the 11-character video ID between the youtube tags:

Code: Select all

[youtube]4d-kC2FE3xk[/youtube]


That is all it ever needs, and it is always 11 characters:




Martin.

[Porcy Mane]

Just as a test for a possible P4 industrial layout and for a but of fun I tried some wagons around a 6" radius curve.

First I tried it in 00 to check for buffer locking etc whilst hauling & propelling. Surprisingly it worked ok.



I then moved on to P4 and introduced a bit of transition between the the straight curved track meaning the radius at the vertex of the eclipse would be somewhat tighter than six inches. Part two is probably the most illustrative. I had to remove the inside buffer on the loco to prevent the three links becoming taut at the tightest part of the curve. Buffer removal would probably not have been needed if I had sprung the couplings or used longer links. Once again all worked OK.



P

[Enigma]

Point work on 'Braynerts Sidings' is based on the geometry of Peco Setrack. Minimum radius through some pointwork is probably about 18" I know this will be an abomination to some - but Rule 1 applies! All my wagons and 4 coupled locos go round fine. Due to increasing years (and an over ambitious track plan) I am having problems with 3-links, even with magnetic bottom links etc. I have tried Dinghams (of both varieties) and found making them up rather a 'toil'. In standard form they will work even on the tight curves but I think that, at times, they do put a side stress on some hooks, especially if two wagons together both have 'long' buffers and this can result in derailments. I have now devised a 'super hook' (based on one seen in a video) and this allows more side play and will hopefully solve the problem. They don't look particularly pretty but in this case, for me, I can live with it.

[Hardwicke]

Just as a test for a possible P4 industrial layout and for a but of fun I tried some wagons around a 6" radius curve.

First I tried it in 00 to check for buffer locking etc whilst hauling & propelling. Surprisingly it worked ok.

I then moved on to P4 and introduced a bit of transition between the the straight curved track meaning the radius at the vertex of the eclipse would be somewhat tighter than six inches.

P

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