Track undulation - derailment?

Mobi

Mobi

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I ran trains after few weeks of gap and then on a particular curve, trains frequently derailed.

On closer inspection, it seemed to be due to recent weather, ballast washed away from underside and section of track exposed as airborne.

When trains moved over it, it was undulating up and down a bit. Is it what causing the derailment?

I have fixed the track with gravel and now it moves only a tiny it and since then trains have not derailed.

Since I run Playmobil loco and rolling stocks, the wheels are all plastic. Will the situation be different with metal wheels?

PS: my tracks are all LGB (and R1 radius curves).
 
Your track is newly laid and is just settling. You have identified the cause of your derailments. The newly laid balast will move and "lock together" and compact over time and the soil underneath will likewise compact or move with relativly little weight on or around it creating undulations. Also with all the rain we have had it is quite probable that some balast has washed away and the soil is more likley to "subside. Just part of the everyday maintainace of a new garden railway. Enjoy.

That, or a large sinkhole is about to open up near your house and swallow your railway, you and your house :o
http://www.telegraph.co.uk/news/picturegalleries/worldnews/9908055/In-pictures-sinkholes-craters-and-collapsed-roads-around-the-world.html Ooh I'm cruel.

Max
 
The only derailments I get, which fortunately are very few, usually occur in two ares on my railway. In both cases it is due to movement of ballast. A quick repacking usually cures the issue. ;D
It seems that large scale locos - maybe smaller scales as well - are not happy on an uneven lateral movement but seem to cope well with undulating track. This was a tip given to me when I first laid my track by a long experienced garden railroader.
 
I have found that rolling stock with only four wheels has a tendency to not like undulating track. That said, Playmobil freight and passenger cars have a longer wheel base than most four wheel LGB cars. If there is not enough up and down movement in the trucks, the cars tend to derail at less than perfect track.

Rolling stock with two four wheel trucks fairs much, much better. As each truck represents a small piece of rolling stock. With the wheels close together, the ups and downs in the rails are not an issue.

I run a majority of field railway cars. I've found, over the past twenty-two plus years of garden railroading, that they hardly derail.
 
Mobi said:
I ran trains after few weeks of gap and then on a particular curve, trains frequently derailed.

On closer inspection, it seemed to be due to recent weather, ballast washed away from underside and section of track exposed as airborne.

When trains moved over it, it was undulating up and down a bit. Is it what causing the derailment?

I have fixed the track with gravel and now it moves only a tiny it and since then trains have not derailed.

Since I run Playmobil loco and rolling stocks, the wheels are all plastic. Will the situation be different with metal wheels?

PS: my tracks are all LGB (and R1 radius curves).
Click to expand...

:) One phenomena that you need to consider, is what is called twist. This is the major cause of derailments, particularly with 4 wheel wagons. Another is the ballast itself. If you are using rounded peebles, dig it all out and start again (I kid you not.. there is no cure), this time use coarse angular chip. Also doesn't hurt to compacted this chip a bit to help maintain level (and use a spirit level to get the track even. If you get the bubble going one way then the other, and back again, then you have put a twist in your track....derailments gauranteed!)
 
Gavin Sowry said:
:) One phenomena that you need to consider, is what is called twist. This is the major cause of derailments, particularly with 4 wheel wagons. Another is the ballast itself. If you are using rounded peebles, dig it all out and start again (I kid you not.. there is no cure), this time use coarse angular chip. Also doesn't hurt to compacted this chip a bit to help maintain level (and use a spirit level to get the track even. If you get the bubble going one way then the other, and back again, then you have put a twist in your track....derailments gauranteed!)
Click to expand...


Are you on the level?
 
Gavin Sowry said:
Another is the ballast itself. If you are using rounded peebles, dig it all out and start again (I kid you not.. there is no cure), this time use coarse angular chip.
Click to expand...
Ah yes, the use of 10mm size gravel or pea shingle. Mistake #1 I made with my railway. You might just live with it but as Gavin says, dig it out and start again. You can use the left over stuff to make a nice "crunchie" path to alert you if burglars are about. That's what my neighbour did with my dug out and recycled gravel. You know what, it works. They caught a couple of scroats one morning at 5am casing their place. I was next in line.
Max.
 
Mobi,
When you dug out your line before you laid the ballast, did you Consolidate the hole (Trench)? By this I mean did you make walk in it or bash it with a lump hammer or something? This is a worthwhile excersze when digging track bed as you will have loosened soil whilst you were digging it. It is also worth while lining said hole with some kind of Weed Barrier, my choice is a thick builders Black Membrane. But old Black Rubble Sacks will do just as well, cut in to Trench Size lengths.

Good luck with your repairs, and yes Max you are cruel!
JonD
 
I have re-ballasted the base of track and train is running fine now :D

Most part of my tracks is on hard slabs and only a little bit is on soil. It is the curves on soil which was causing the problem. But now I have re-leveled the track and stopped its undulation, train ran fine after that.
 
Mobi said:
I have re-ballasted the base of track and train is running fine now :D

Most part of my tracks is on hard slabs and only a little bit is on soil. It is the curves on soil which was causing the problem. But now I have re-leveled the track and stopped its undulation, train ran fine after that.
Click to expand...

:D In future, every time you have a derailment, you should check the track to see if it was the cause. Check line for peaky joints, and cant measurements for twist. Pays to periodically check the track like this as part of normal maintenance.
 
Hi

To pin point the exact position of a track twist can be a little difficult. Some time ago as an aid to track maintenance I built a couple of wagons using the ‘bubbles vials’ from cheap spirit levels.
The details of the wagons can be found in Garden Rail June 2010.

Mice One
 
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