You have to be so careful with track laying.

[Robert Stokes]

Earlier today I ran some new wagons round the layout. It was a train of six wheeled milk wagons. At one place some of them derailed and the train split. I put things right and ran the train round again. The same thing happened at the same place. I examined the track carefully. This wasn't easy because it was near the back of a 24" wide baseboard set 48" above the floor and I am only 5' 7". In fact I had to get a step ladder so that I could lean over and look at it directly from above. I could then see a slight dog-leg where two pieces of flexi-track joined. When I had corrected this the wagons ran round with no trouble. A mystery about the situation is that no rolling stock, engines, wagons or coaches, had previously "found" this dog-leg.

[doilum]

Is it a new layout? Has the central heating come on for the first time in recent weeks? Only ask because I have had similar experiences on my SM32 greenhouse track. Easier said than done is to stagger the rail joints so that two lengths of flexitrack do not butt up together. Good ballasting will help too.

[Robert Stokes]

The layout is several years old and is in a shed which I haven't yet found the need to heat this autumn. So far I've found that just putting on a coat is enough.

[Vistisen]

1 hour ago, Robert Stokes said:

Earlier today I ran some new wagons round the layout. It was a train of six wheeled milk wagons. At one place some of them derailed and the train split. I put things right and ran the train round again. The same thing happened at the same place. I examined the track carefully. This wasn't easy because it was near the back of a 24" wide baseboard set 48" above the floor and I am only 5' 7". In fact I had to get a step ladder so that I could lean over and look at it directly from above. I could then see a slight dog-leg where two pieces of flexi-track joined. When I had corrected this the wagons ran round with no trouble. A mystery about the situation is that no rolling stock, engines, wagons or coaches, had previously "found" this dog-leg.

We're they Dapol 6 wheelers? I have three of them and they are all very fussy. I also have a Hornby 6 wheel tank that has no problems . Pushing these three Dopol wagons with a loco through hand built points has destroyed my faith in my own point building abilities.

[Robert Stokes]

I think they are Dapol ones. (I'm indoors now so can't easily check.)  Also, prior to running them, I checked the wheel back-to-back settings. Several of them needed easing out a little.

[Phil Bullock]

At Calne show a few years back I set up the Carlisle - Swindon milks - 25 tanks with a 40 up front. Looked cracking! Round it came on to the scenic part of the layout when the rear tank derailed …. And every other tanker in the train slowly fell over towards the inside of the curve. Cue much hilarity and comments about yoghurt!

 

The upshot was I checked the B2B on all the wagons …. All Hornby. Some were significantly out …. And using my truck tuner opened up the centre pair of axle boxes to give the centre axle more float. Touch wood they are now reliable…

 

They are undoubtedly sensitive vehicles…

Edited October 26, 2021 by Phil Bullock

[MikeJT]

If they are indeed the Dapol 6 wheelers then that's likely to be your problem rather than your track.

 

Have a look at this thread:

 

Dapol 6 Wheel Milk Tanker

Hope that helps.

 

Mike

 

[AndrueC]

I think alignment matters most. I've developed a few rough spots since my track was fixed down due to various projects. Even with N-scale it's surprising quite what you can get away with. The trains might click/clunk a bit but they keep on rolling

[The Johnster]

3 hours ago, Vistisen said:

We're they Dapol 6 wheelers? I

The first thing that occurred to me when I read the original post.  I have never had any Dapol coach or wagon that did not immediately benefit from having it's wheels removed, given an exciting opportunity of a new career*, and replaced with Hornby or Bachmann equivalents, and I have now learned by experience to remove the flaccid NEM couplings and their housings in order to replace them with Bachmanns' in Parkside PA34 mounts.  Any 6 wheeler is asking for trouble in my bitter experience of them, and if all else fails I suggest the Five79 (Chivers) kit approach of a dummy, non-turning, centre wheelset with the flange and tyre filed down to a flat which clears the railhead by a smidgeon; I have an LMS fish van from this range which runs perfectly, though it is of course really a 4 wheeler!  The dummy wheels are not obvious unless you look closely (so don't look closely...) on 30" radius turnouts.

 

Pity, because Dap do some otherwise good stuff at very reasonable prices.  I believe the Hornby miltas are the old Lima model with better couplings (well they could hardly be worse than Lima's, could they?), and my memory of the Limas was that they ran well enough despite the pizza cutters.  Checking and adjusting B2Bs is never a waste of time whatever the make, though.

 

Assuming you have laid your track smoothly between adjoining pieces on a level and rigid baseboard, you should be able to achieve pretty reliable running with RTR stock so long as you respect the minimum radius specification, and ensured that all wheelsets are to gauge, aligned, and run freely.

 

 

 

*In the landfill industry...

[Robert Stokes]

Thank you for some interesting replies. I will do something about the wheels if these wagons give further trouble.

[Il Grifone]

14 hours ago, Phil Bullock said:

At Calne show a few years back I set up the Carlisle - Swindon milks - 25 tanks with a 40 up front. Looked cracking! Round it came on to the scenic part of the layout when the rear tank derailed …. And every other tanker in the train slowly fell over towards the inside of the curve. Cue much hilarity and comments about yoghurt!

 

The upshot was I checked the B2B on all the wagons …. All Hornby. Some were significantly out …. And using my truck tuner opened up the centre pair of axle boxes to give the centre axle more float. Touch wood they are now reliable…

 

They are undoubtedly sensitive vehicles…

 

That's why I don't like tangle tension-locks! I once had a twelve coach train fall off the layout due to the wretched things....

 

Six wheel vehicles are always a pain. The centre axle must be free to move laterally and vertically without twisting and preferably be sprung to keep it on the rails.

 

Dog-legs can appear mysteriously (the inverse of things disappearing...). I always make sure the rail is pre-curved at the ends, so that it falls naturally into position. It may be necessary to slide the sleeper moulding off to do this and not be afraid to cut webs. The sleepers should be closer together at rail joints anyway. I have a point* that keeps dog-legging. I shall have to curve the thing. Cutting a few webs in the centre should do it. The crossing nose is made badly (not by me - the manufacturer - as a cue they make H0 track and sell it as 00!)**

 

*   As it's on an American layout (so H0 is fine), perhaps I should write, "Switch"?

** To be fair, they are not alone in this.

Edited October 27, 2021 by Il Grifone

[DCB]

Flexi does dog leg at rail joints.   The sharper the curve the more it dog legs.    Especially the inner rail as it's difficult to brace it if you cut the rail chairs away for the rail joiners.  I brace the bad bits with self tapping screws against the outer rail but if I can I prefer to use set track for any curve I can get set track of a large enough radius to suit.  Set track rail seems less flexible than flexi, and much less prone to straightening out so I also use set track rail in flexi sleepers for awkward bits of track likely to try to straighten out if laid in flexi.  

I seem to find a new dog leg every time we get a new locomotive these days.

[Andymsa]

There are a couple of things you can do to stop the dogleg of flexitrack on curves because of its tendency to want to straighten. First is to put a very small curve into the end part of the rail either with smooth faced pliers, and or offsetting the rail joints so the are not across from each other. And the final tip is putting in one of the Peco curved track templates and soldering the rail joiners. Using these methods I have not had one derailment on these types of rail joins.

[RobinofLoxley]

Having just successfully layed my first and only piece of curved flexitrack I now consider myself an expert. Its held down by track pins and cant go anywhere. The first 75mm at each end are held straight in line with the points that it meets at each end but doubtless there are many places where that might be difficult in the modelling universe. Lol. 

[scottystitch]

Where there is going to be a join on a curve of flexi-track (Peco Code 55) I join them on the straight first, before laying, and solder the joints.  The curve is then formed from one long piece of flexi rather than trying to join two pieces on the curve. No kink.

 

Best

Scott.

[Halvarras]

Be careful not to solder too many rail joiners! I laid the track (Peco code 100) on my layout during the winter months and when the first hot weather of the following summer arrived the reverse curve on the branch line warped badly, and exerted enough pressure to break the copper-clad sleeper at the baseboard edge. I had forgotten how much model track can expand just like the real thing in hot weather! Remember to leave small expansion gaps when laying yard lengths of flexible track, and especially so if soldering rail joiners in certain locations - but the gaps should be in straight sections wherever possible.

 

OR.........lay your track during hot summer days (when you'd rather be outside......! )

[scottystitch]

Indeed, it pays to restrict the soldered joint sonly to the joins on a curve.

 

Best

 

Scott

[doilum]

Start by laying the curves?

[Andymsa]

All my metal rail joiners are soldered. Where I allow for expansion is on the isolation rail joins. 

[Robert Stokes]

I'm not convinced that soldering rail joiners is a good idea, especially if this means several yards are joined to make a really long run. I wonder whether the whole lot can expand only at its ends. This is especially true if, like me, you glue down the track. It is quite possible that some part of a rail is glued to its sleepers and this will make it difficult for the rail to slide along as it expands. Anyway, if you use dropper wires on every piece of track then the track joiners are only there for alignment. In fact on another forum I have read about someone who does not use track joiners at all.

[The Johnster]

There is no need to use track joiners for electrically connecting sections of rail if you are going to solder the sections together or use dropper wires so that the rails are conncected beneath the baseboard, but I still consider them advisable in order to assist with alignment in track laying.  DC isolated sections are, IMHO, better achieved with cuts in the rail over the sleeper web base than at the ends of sections where the lack of something that physically holds the adjoining rails together in alignment can cause doglegs, and doglegs are best kept on dogs...

[Phil Bullock]

I wouldn’t advise soldering lengths of track in any environment that is subject to extreme temperatures! The dog legs in our fiddle yard had to be seen to be believed when we were out next to a radiator at our first show… 

 

Expansion is definitely worth thinking about and is the reason why I am not laying our fiddle yard boards which are 3ft wide with a single length of track. All have a minimum of two lengths of track to allow an expansion joint in the middle, critical as the track is soldered to screws at the board edges so expansion can only be towards the centre. There is of course more scope to allow for this on a layout that is not portable.

[Il Grifone]

11 hours ago, The Johnster said:

There is no need to use track joiners for electrically connecting sections of rail if you are going to solder the sections together or use dropper wires so that the rails are conncected beneath the baseboard, but I still consider them advisable in order to assist with alignment in track laying.  DC isolated sections are, IMHO, better achieved with cuts in the rail over the sleeper web base than at the ends of sections where the lack of something that physically holds the adjoining rails together in alignment can cause doglegs, and doglegs are best kept on dogs...

 

I use insulated rail joiners, which are not ideal, but better than nothing. Lengths of loose rail are asking for trouble, even secured by the sleeper webbing. ( I usually cut these as the sleepers are usually too close together - it seems it was too difficult for track manufacturer's to measure 2' 6"! - Peco excused as their product was intended for the American market)

 

According to my calculations (for what they're worth) a yard of rail will expand by a bit over 0.1mm for a rise in temperature of 1 degree Celsius.

It appears to be not just our problem (see photo):

https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html

 

The real thing used to allow 1/4" gap for expansion (presumably allowing for a 20 degree rise in temperature?)

 

The first site I looked at gave coefficients in 'degrees F' whatever that means.  

 

Edited October 29, 2021 by Il Grifone

[RobinofLoxley]

Just to be completely clear on the subject of linear expanson coefficients, plain steel bar has a coefficient of 0.000011.

 

So a 1M bar expands by eleven millionths of a meter per degree (C). That is eleven thousandths of a millimeter, or to put it another way, you need 90 degrees of temperature change to generate 1mm of linear expansion. So linear expansion isnt very much, however the problems arise when the said bar is restrained so that it cannot expand along its length and the resulting dimensional change has to express itself sideways.

 

So a feature like an IRJ, which is compressible, will be effective in containing expansion. But long sections of soldered track will be vulnerable. I generally leave gaps of about 0.5mm per metre on continuous track sections, plus I have many plastic IRJ's. I have to cater for 40C temperature range and havnt had any issues yet. Stock doesnt seem to notice much larger gaps than 1mm between rails provided they are in line.

 

I have droppers on every track piece so technically dont need fishplates but would never leave them out. As has been said, they do help to hold adjacent track pieces in alignment, and having droppers sometimes there will be slight sideways forces. With light pony trucks (I am 100% steam at the mo) they can easily bounce out if tracks not perfectly in line.

 

 

[Robert Stokes]

3 hours ago, Il Grifone said:

According to my calculations (for what they're worth) a yard of rail will expand by a bit over 0.1mm for a rise in temperature of 1 degree Celsius.

 

 

Could you please explain how you got this figure as it seems very high. It would imply an expansion of 2mm for a yard of track if you laid it at 10 C and the temperature went up to 30 C.

    

Nickel silver is actually 60% copper, 20% nickel, 20% zinc. The expansion rates for these metals are 0.0000165, 0.0000134 and 0.0000302 cm per cm per degree Celsius. Allowing for the composition this averages at about 0.000019. This gives for a yard of track (call it 90 cm) over the same 10 to 30 C range

   0.0000193 x 90 x 20 = 0.034 cm 0r 0.34 mm.

so enough to matter but no where near as much as your figure.

    

Edited October 29, 2021 by Robert Stokes
missing decimal point