Dapol pannier de-railing is all as it should be?

[t8hants]

Eager to try out my just laid O gauge garden track (Peco code 124) I was slightly disappointed when my Dapol pannier derailed after only a few feet, this I put down to it not being properly flat yet, it is laid on stone chip roofing felt.  I was also concerned that my tightish radius was too tight, it’s about 100mm bigger than a No2 curve.  I tried my loco on a quadrant of No 2 set-track which it went around Ok, but with a distinct rumble of what I presume was the flanges running on the plastic rail chairs.  I measured the over flanges distance on my loco and got 30.5mm and the width of the top of Peco rail is 1.5mm, so it seems to my inexperienced eye that it is quite possible for my loco to fall between the rails.  Is the over flange measurement on my pannier correct for the model please?

 

Thanks.......Gareth

Edited August 23, 2021 by t8hants

[Simond]

Gareth,

 

not sure I understand your measurements, but I hope this will help:

 

modellers often use “back to back” measurements - this isn’t terribly prototypical, but it’s easy. Use a digital caliper if you have one (they’re a tenner in Lidl if you go on the right day) and measure parallel to the axle.  You should have a measurement of 29mm with a tolerance of  +/- 0.2mm.  I’d be very surprised if they’re wrong on a loco but it could happen.  It’s more common on wagons & coaches.

 

I’m sure the tyres of the loco will be wide enough, I’d expect them to be between 3.2 and 4.5mm.

 

the flanges will be between 0.5 & 0.8 or thereabouts which ties in with your “over flanges” measurement.  
 

the distance between the rails is 32mm. If you have an “over flanges” of 30.5, the tyre of the wheel would need to be less than 1.5mm wide to fall into the four foot, but it’ll be something over 2.7, so that won’t happen!

 

I could have saved myself some typing, it’s all here;

 

https://www.gaugeoguild.com/revised_manual/New_manual_files/Sept 2017 part 1 Standards..pdf

 

Hope this helps

simon

 

 

 

[t8hants]

Hi Simon, thank you for taking the effort to do the typing.  I have just measured the back-to-back on the loco and all are 29.2mm ish, so the loco is Ok.  I am slightly puzzled by the apparent bumping along the rail chairs on the set track curve, but it stayed on, which is more than it did on my trackwork so far.  Having eliminated the unlikely, it must be the most likely, which is my trackwork needs a lot more fettling yet.  It has a long way to go before I risk my precious Adams O2 on it.

I also found the O gauge guild standard sheets, but I have a degree of learning to do before that fully sinks in.

[brossard]

I'm using Peco code 124 on my indoor layout and there are lots of Dapol locos running on it (along with some from the likes of Minerva, Lionheart and even Fine Scale Brass).  I have never noticed anything like the rumble you describe.  It's a BLT so no particularly challenging curves.  If you check the FB link there's a video of a recent shunting sequence so you can hear for yourself.

 

I was just remarking the other day that our most recent running session did not have any derailments (apart from me running through a catch point the wrong way).

 

I can't recall what No 2 radius is but as long as it is at least 4', there shouldn't be issues with Panniers.

 

Good luck with finding the solution.

 

John

[47606odin]

What wheels have you got fitted for it to run on the rail chairs?

[Happy Hippo]

Gareth,

 

If you have successfully run the pannier on Peco set track 2nd radius curves which is a 40.5" radius (for Brossard!) then you should have no problems on larger radius curves.

 

Simon, in his usual thorough fashion, has covered the gauging and the need for consistency in the various dimensional areas issue.

 

So a couple of pointers as to the derailing issue:

 

Does the loco derail at the same point on the curve every time?

Is it at a track joint?

Are your track joints staggered or opposite each other?

Apart from running on roofing felt, what type of surface is underneath it?

Is that surface flat?

Is the track flat?

 

It can sometimes be a rather long winded operation, but you need to systematically check each factor before moving onto the next one.  

It could be a combination of a number of factors.

 

You mentioned that the track is not fixed down yet, so consider carefully how you intend to secure the track when that time finally comes.  Don't be tempted to put a pin in the centre of the sleeper, but secure the ends as this stops the potential for the sleepers to bow.  As an aside remember that pins going through the mineral felt topping will create an entry point for water to get under the felt.

 

Getting the track alignment spot on is also very important.  We can get away with 'flat curves' where the inner and outer rails are at the same height.  Derailments can still occur on such track, but they are guaranteed where you have an adverse camber:  The inner rail being higher than the outer rail.  This need only be a fraction of an inch but it is enough to tip the balance.

 

The real railways use what we modellers term 'super elevation' where the outer rail is higher than the inner rail.  It can be achieved with care and could help with your running issue.  Again it need not be much.

 

Rather than test curves (and straight track, pointwork etc) with a loco, I've always found that pushing a couple of light 4 wheelbase wagons through to check everything is all right is a far more effective way of checking if alignments are ok. In my experience, any minor issue will be indicated with a derailment.  Always propel the wagons as if you pull them through the pulling will tend to guide them rather than the leading wheelset finding the  problem.

 

As far as the noise is concerned,  if the track is not secured then some of it could be down to vibration as the loco moves along the track.  If the track is secured to a baseboard, then it is quite possible that the baseboard and it's frame are acting as a form of loud speaker for any sound coming from the loco and rolling stock.

 

 

 

 

 

 

[t8hants]

51 minutes ago, 47606odin said:

What wheels have you got fitted for it to run on the rail chairs?

The loco is straight out of the box as supplied by Dapol, but there was a distinct brrrr as it was going along on the set track test piece.  Further tests on a straight length have not repeated the noise and it won't always do it on the curve.  Thinking about it, as the track was on the carpet and the floor is not an easy place for me to get to these days, I wonder if I had one wheel slightly mis-aligned, but there was no visible shaking and I would have expected more of a bump-bump-bump, rather than the gentle brrrr I could hear.

                Returning to the derailments, I am convinced they were caused by slight deviations in the track, which is not fully fixed down yet as I await more track pins.

[Nearholmer]

Another thing to watch for when pinning or screwing track down is not to nail/screw down too hard. If you do, it can deform the sleepers, causing the gauge to go narrow and trains to ‘jump out’ of the track.

[New Haven Neil]

There's certainly no issue with Dapol loco flanges and Peco set track, as someone mentioned above, I also have Minerva and Lionheart Panniers and all run superbly on the track and points, including a 90 degree setrack curve

 

It does sound rather like you had the centre drivers off the track in your test?

 

[pwr]

Is it possible to replicate this in a video and post it here?

 

Paul R

[doilum]

2 hours ago, Nearholmer said:

Another thing to watch for when pinning or screwing track down is not to nail/screw down too hard. If you do, it can deform the sleepers, causing the gauge to go narrow and trains to ‘jump out’ of the track.

And with brass kit built locomotives, overtightened chassis / body screws can induce just enough twist in the frames to cause derailment. It took a while to work out why several of my locos would only run 100% in one direction only.

[t8hants]

I am now discounting any fault with the loco apart from my inability to place it on the track correctly.  That’s a good tip to push wagons around the track to check for track issues, save seeing my loco taking a dive into the pond.  You will have to excuse me; this is my first venture into garden O gauge and I probably was expecting things to be slightly more tolerant than they appear to be. The track panels are fixed on the ends of the sleepers, but because I am short of track pins, I have until now been staggering them up the length of the track panel, and possibly fixing them too hard. They are soldered together for power continuity   The under framing is two layers of 5” wide ¾ ply, with the top layer chamfered on the edges to round the felt over, screwed into 4”x 2” on edge, as most of the track is only single line.  It is level and flat, jungle joinery I can do. Railway wise this is very much an on the job learning curve. 

                One quick question how many feet apart should one consider putting power booster cables in around the track?

[Simond]

I would tend to put a pair of busbars around the garden layout, and supply each yard of track directly from them by soldered wires. 

 

This allows the fishplates to slide, and they will certainly need to, the curent weather is miserable but high teens, and it can get into the 30's in direct sunlight, even hotter perhaps.  When it's below zero (does it do that in the IoW?) the rail will contract around 16 microns per degree C for each metre length.  So perhaps half a millimetre per yard.  Add a few lengths together and you need to allow for it, or your track will either break joints, break free, or buckle.

 

And if you are not reliant on the fishplates for continuity, you can put a drop of oil on them, and they'll last rather longer.

 

belt and braces, but I hate doing jobs twice!

 

Simon

[t8hants]

Thanks for the advice, I can see I have not allowed sufficient droppers onto the busbar at the moment.  I think I am Ok with the track expansion, as I have allowed 1mm per joint/yard.  Thanks to Happy Hippo’s tip of pushing trucks around the trackwork to test it, I can now see exactly where due to absent fixings, there are slight twists that are causing the derailments.  As I now need to get hold of other bits and pieces the P-way gang have been put on other duties.  The Dapol pannier has been returned snug in its box awaiting the day when it can make a complete circuit.

[Stephen Freeman]

Never mind the ambient temperature, more of a problem is direct sunlight on rail at almost any time of the year. 1 mm per yard may not be enough.

[pwr]

1 hour ago, Stephen Freeman said:

Never mind the ambient temperature, more of a problem is direct sunlight on rail at almost any time of the year. 1 mm per yard may not be enough.

 

I've had that problem when I set up Black Notley outside. Nearly burnt my skin on the rails. Not going outside in August again!!!

[jcm@gwr]

20 hours ago, pwr said:

 

I've had that problem when I set up Black Notley outside. Nearly burnt my skin on the rails. Not going outside in August again!!!

 

Wouldn't have happened this year! 

[pwr]

On 26/08/2021 at 06:05, jcm@gwr said:

 

Wouldn't have happened this year! 

 

I know but it would probably have got soaked instead!

 

Paul R

[doilum]

Which is why my SM32 is in the greenhouse. Each running session is preceded by a track inspection for expansion/ contraction issues. It today was fine. In midwinter I may have to swap over some of the Peco rail joiners for ones with a 3mm section of rail soldered midships. These are then removed in the spring. Current continuity is not an issue as Kayti is live steam.