Trouble with de-railment over two curved points.

[topsy11]

Hello.

 

I've been plodding along building my layout and I seemed to be finally making good progress and was hoping to get the fiddle yard 90% completed this week but seem to of hit a problem tonight.

 

I've got two Peco ST-244 right hand curved points which look like this....

 

 

They're going to be on a hidden part of my layout and so I need maximum reliability and error free running.

 

Whilst laying the track I've ran wagons over the points to ensure they run over them OK and encountered no problems or de-railments.

 

Now I've laid a little more track I've started running locos and wagons over the point but experiencing quite a few de-railments over the points. 

 

I've not had chance to spend a long time messing with the points but from a quick google it seems these curved points are a nightmare anyway??  Its already a pain to get access to this area of the loft so would I be best biting the bullet now and using some medium radius points instead of these curved points? It will cause a bit if work messing about with wiring and moving point motors etc but I can't afford any derailments in this area if possible.

 

Many thanks.

[michaelp]

Could the problem be the radius of the Set track point, I ask because I have a Streamline curved point on my layout and have had no problems whatsoever in either direction.

 

Michael

[topsy11]

Thank you.

 

I'll have a check tomorrow regarding the wheel and track distances.

 

I'm not sure if the radius is too tight for the wagons - TEA and KTA wagons tried so far although the locos themselves Bachmann 37 and Hornby 60 run over the points OK.

 

Cheers

Mark

[RFS]

Are you satisfied that the transition from the turnout to the plain track is smooth?  I ask because it seems the two pieces of concrete track come quite close to each other at one point.  Might be useful if you could perhaps post a photo of the two turnouts taken directly above them, if you can access them!

 

I have a large fiddle yard where all 10 turnouts at each end are curved, but they're Peco code 75 ones and I don't have any issues.  But you do have to lay them very carefully to ensure they are flat and there's no slight kink in the track joins.

[Ray H]

It might be helpful if you can ascertain exactly whereabouts the wagons are derailing.

 

Is the track level?

 

Can you place a thin piece of card under the outside of the curve just before the start of the blade to encourage the wheels to take the right hand most route if that's the route where the problem arises? Derailments of wagons taking the larger radius route suggest something more fundamental.

 

Can you lift the points temporarily and experiment with them in a more accessible location?

[topsy11]

Thanks guys.

 

I'll have a proper look at it tomorrow as I come out the loft to watch top gear and a bit late now.

 

I'll check over everything fully tomorrow - I was just wonfering if it was worth persevering with the two ST244's or to ditch them altogether. Ideally I'd like to keep them but only if I can get them running properly!!

 

I'll have a play tomorrow and report back.

 

Thanks

[Theakerr]

Based on my own experience and that of at least one friend, I assume that your points are code 100, that you are using later model rolling stock with "modern  fine" flanges, that the de-railment occurs as the stock try to go over the frog point and that you have checked the back to back.  Further I am assuming that the de-railment is when the stock is going on the outermost curve of the points.  Then the solution is almost certainly to add a strip of 0.010 to 0.015 plastic strip onto the rail side of the check rail.  Basically code 100 track is robust but pretty crude having been developed in the days of very crude wheel flanges so that they would not de-rail.  With todays standards the check rail does not pull the wheel far enough over and it hits or goes the wrong way around the point frog.  Very frustrating to diagnose because it doesn't do it every time.  Depends on the stock item speed and Sods Law

[michaelp]

That bloke 'Sod' has a lot to answer for!

[Kenton]

How were the points secured to the baseboard?

 

The geometry of Peco curved points is not particularly great and they are very easy to distort - even easier to over-egg the transitions into the points. Be very wary of following one curved point with another (without some transition). They tend to derail bogie stock more easily that short wheelbase wagons.

 

Simply hand pushing a wagon through a point is a very inadequate test. You will inadvertently apply forces that will never happen when stock is propelled by a loco - especially downward forces. A better test is to propel a long (5+ wagons/coaches) using the powered loco.

 

There is a natural tendency for any stock to jump the frog to the outer curve - this centrifugal force is even more exaggerated when passing through two curves.

[HLT 0109]

Mark,

 

I have a similar configuration on my layout - thankfully in an accessible position and I can relate to your experience - although my points are Hornby.  In my case the problem was with the inner radius and I overcame it eventually.  Firstly, one of the points had not been laid level (though yours should fine as they appear to be laid on to plywood without a join); secondly the transitions benefitted from adjustment as RFS suggests; and thirdly, I do have a piece of thin plastic stuck to the side of the check-rail on one of them as Theaker suggests.  I do occasionally have a derailment with my Backmann Jinty, which has quite a long 0-6-0 wheelbase, when travelling from the heel of the point (from the right of your picture) though my 9F seems to cope!

 

I think you should persevere with the curved points as they do give a nice flow in such a location.

 

Harold.

[Dzine]

Hi topsy 11,  Have a look at the first outing of Inside Track in BRM mag February.  I've done a detailed account of the point, its problems and possible solutions.  Hope this helps.  Kind regards Paul

[topsy11]

Hello.

 

Well a quick update from me....

 

Had another look at the curved points - I just couldn't get anything to go over the points without derailing. on a 5 wagon train it would only be one set of wheels that'd come off but sometimes on a different wagon.

 

I spent a bit of time playing but just couldn't stop them de-railing. The only thing I didn't try was to modify the point with some plastic on the check rail.

 

Anyway I've replaced the curved points with some medium radius points and can so far report 0 derailments!!

 

It doesn't flow quite as nicely, to the eye, as the two curved points did but the trains seem to prefer the normal points over the curved ones. I can hopefully lay a little more track in the fiddle yard at the weekend and give it a bit more testing and then just tweak it to make sure its all perfectly flat and aligned as I didn't want to get as far as I did with the curves and run in to problems!!

 

I'll update again at the weekend for anyone interested.

 

Thanks

[Joseph_Pestell]

We have had this one before! The geometry of Peco Setrack points is rather strange and does lead to derailments for facing moves. Definitely worth looking at other solutions.

 

Looking at your photo, I think you probably have room for either medium radius Streamline or curved Streamline turnouts. It will mean the track being a tighter radius but you are much less likely to get derailments on plain track than on pointwork.

 

You might also gain by changing them around. The first point going to the branch, the second point doing the split to double track nearer to the tunnel mouth.

[sub39h]

Were the points new or second hand? I am currently making a set track layout as a test bed and I have four old Hornby curve points that would only work in one direction. It seemed to be that all stock would derail. I swapped them for some brand new Peco ones and voila the problem is fixed!

 

There are a couple of other things to consider. I know you mentioned on another thread that it was just the first wagons that derail. Was it the Class 60 that was hauling them by any chance? The Hornby Class 60 (as lovely a model as it is) has a quirk in that the coupling is attached to the body, not the bogie. As a result, it doesn't swing very much and wagons derail on setrack points because the coupling doesn't swing enough. 

 

Final thing, the Bachmann TEA is incredibly light. It derails if you even look at it the wrong way. If you're careful you can get the ends of the tanks off. Some people put pennies in them to weigh them down. Simple and effective!

 

Good luck!