Minimum curve for running locos

[pidge456]

Hi everyone, I have limited space for my layout but would like to try and extend what I have. What is the minimum track radius that locos would run on safely 2nd radius ???. I have several 4-6-2's which run fine on 2nd radius could I go any lower? I'd like to buy at some point a Cock o the north 2-8-2. Is is just loco length that is important or wheel configuration. Many thanks.

[walkingthedog]

Don't use 1st rad unless you really have to, perhaps in a siding.  The bigger the better. Don't be afraid to use Flexi track, very useful. 

 

If possible stick to 3rd and 4th. 

[96RAF]

Its usually written clearly on the loco box, but in general if its not an 0-4-0 then stick to rad 2 and above.

[pidge456]

Its usually written clearly on the loco box, but in general if its not an 0-4-0 then stick to rad 2 and above.

Ok thanks didnt realise it was on the box.

[96RAF]

@Midge

It usually written as (e.g.) 438mm radius not 2nd rad from memory so you need to refer to the track geometry download figure for the dims of each radius, although 438mm = 2nd rad.

[walkingthedog]

Do the other companies do it RAF?  If a Hornby loco doesn't have a minimum rad that usually means it's OK for first. 

[Buz]

 Hi pidge456

 My layout is tiny but does not go below 2nd anywhere don't go to first under any curcumstances its not worth it.

I can run 4-6-2's no problem but it looks odd.

The key thing is wheels not so much the wheel arangement,

But how many blind wheels it has that is drive wheels with out flanges and where those blind wheels are.

The older loco's often had the center wheel or wheels blind this allowed some pretty big loco's to look daft going round R1 curves that they should not have got round.

The modern loco's often don't have the blind wheels and the coupling rods are not as flexable or loose as they used to be manufactured.

The real railways some times used the same trick to deal with real sharp curves if they had to

regards John

[walkingthedog]

The BR 9F 2-10-0 centre drive wheels are flangeless on the model and on the real thing. Not sure about the real P2.  

[The Doc]

The BR 9F 2-10-0 centre drive wheels are flangeless on the model and on the real thing. Not sure about the real P2.  

The real P2 had flanges on all wheels - and consequently caused problems to the track on the winding mainline to Aberdeen (which is what they were designed to run on).  Mine cannot cope with 1st radius but just about manages 2nd, though being a very long loco, it does look a bit silly.

Regarding first radius curves, the 0-4-0s  are the only current hornby locos that you can guarantee will go around them,  although my Railroad flying scotsman manages it (just), as does my J15 and J94 (unlike my Railroad 0-6-0s) .  The bachmann class 08 copes fine, so I expect Hornby's will too.  Ii's quite possible that Hornby 4-4-0 tender locos and M7 0-4-4 might manage 1st radius, but hopefully someone else could test this if they have the locos and the curves.  The Railroad Bo-Bo diesels and electrics should also cope with 1st radius in theory, but in practice you may find you have to cut away a tiny bit of bogie of chassis to make sure.

Any older "Made in UK" Hornby locos (only available second hand) should manage first radius without a problem, as the centre wheels of 6 coupled locos had smaller (or non-existent) flanges.

 

 

[Postman Prat]

Hi Doc

 

Would the M7 be a problem with regard to 'throw off' at the bunker end, due to only one end of the loco being fixed and half the loco being over the bogie? On the other hand Pacifics don't have a problem so............

 

Not a problem to me, merely speculating.

[96RAF]

Do the other companies do it RAF?  If a Hornby loco doesn't have a minimum rad that usually means it's OK for first. 

 

The only non Hornby loco I have is a Bachy 0-6-0 Jinty and I quote from their Care of Your Locomotive sheet - "B'mann strongly recommend that locomotives, particularly tender-coupled versions and multiple units, are not used on track curvature of less than 2nd Radius geometry i.e. 17.25" / 438mm Radius"

[LCDR]

  Moderrn locos from Hornby, Bachmann and Heljan will not pass round first radius curves comfortably except the little 0-4-0 and 0-6-0s from Railroad range and the very short wheelbase main range ones like the L&Y 'Pug' and the Sentinel diesel. I am not sure if Henry and Gordon from the TTTE range will go round first radius, as I haven't got these (yet) but I think models they are based on did originally.

 

Beware locos like 0-4-4 & 4-4-0 which look like they might go round. There may not be enough 'play' in the bogie to prevent derailing.

[GreenGiraffe22]

I don't know what radius my inside track is, but my Q1 can only make it round in reverse, and even then I had to file off half the running plate because it was pushing up against the tender and pushing the engine off the rails on nearly every single bend! Fortunately, the rest of my engines are mostly fine, The E4 comes off on one bend on the inside but it's part of a station loop so it can go into the other platform just fine! 

[LCDR]

 Also beware if using flexible track, there is a temptation to create bends even sharper than first radius to make it fit. Use a template like 'Tracksetta' to prevent an unusable curve.

[GWR LNER fan 4472]

Green Giraffe - that sounds like 1st radius to me. Although my merchant navy 4-6-2 sometimes has trouble going round 2nd radius.

I have a whole load of r1 curves just sitting around not being used and unlikely to be. I have a few in a curving station siding but I only park trucks there as bogie coaches foul the platform. Any suggestions as to what I can do with them? I have three or four tank engines that run on them happily but nothing else.

[RDS]

I know it is not recommended but I have a layout consisting of 4 concentric ovals, 1st, 2nd, 3rd and 4th radius.

 

All my Loco's run without problems on the entire layout.  That is Bachmann Class 08, Class 20, Class 37, Class 42, Class 47, Class 66 and Class 70.  Also, Hornby Royal Scott, 3 Loco's from the Thomas the Tank Engine Range,  Intercity 125, Stanier 4MT 2-6-4T and Smokey Joe.

 

The only Loco that would not run around 1st Radius was a Hornby Duchess of Gloucester 4-6-2.  I say 'was' because I sold it.

[GeoFF03]

I have 1st radius curves on my layout, and out of quite a considerable number of locos only one (an 0-6-0 from Bachmann) absolutely refuses to go round it.  With the steam models it does mean that some of the detail parts have to be left off (drain cock pipes, steps etc.) and tenders have to be set further back but I'm not particularly bothered about that.  The larger diesel locos (Co-Cos like the Class 55 or 37) I tend to run on the 2nd or 3rd radius loops anyway but the smaller ones also run fine on the tigher curves.

[Jimbo1707820979]

Hi Pidge

Just adding my 5-bobs-worth, though I'm very far from being an expert. I have read a couple of complaints in the last few months about Cock of the North derailments. It is a looooong loco. (but very attractive) Maybe some others can contribute more specifically to this thread.