Insulated rail joiners

[Robin Webster]

Perhaps you have heard of Gapmasters. They claim to make perfect electrical rail gaps. Their item number is GM016 for PECO SL-400 flex track.
They are known as American tie and timber company. I have not used their product.

Robin

[Ian McAulay]

Another product I never knew existed! Thank you, Robin.

The URL is: http://americantieandtimber.com/4.html and scroll down; the HOe/HOn30 (009 to us Brits) version is almost at the bottom of the page. They are quite pricy at USD 2.50 per unit, with unstated carriage charge to us on the RHS of the pond.

They will hold rail ends very firmly in alignment as they are soldered. To provide insulation, extra gaps in the copper cladding would need to be filed. They definitely don't address the secondary issue of providing expansion gaps (see previous discussion), but derailment through misaligned rail ends just won't happen.

A slightly inferior home-grown solution, would be to solder an N-gauge copper clad sleeper lengthwise (ie right angles to usual position) under each rail with the gap in the copper under the gap in the rail. Cosmetic bits of sleeper base could then be glued in place to fill in the gaps. However, that wouldn't provide the gauge rigidity of the Gapmaster.

I don't think this what I'm looking for at the moment, but will definitely file away for future reference!

Ian

[Graeme Dunbar]

My attempts at dyeing Peco insulating rail joiners today.






I used Rit DyeMore dye for synthetics and kept the dye hot in an improvised double boiler.

Left to Right: apricot  orange, apricot orange followed by graphite, mixture of apricot orange and graphite, graphite

The colour differences are not so clear here, but a lot more marked when lit from behind. The orange looks raspberry coloured on white paper and a bit more orangy-brown against the sky or cool white light. The orange followed by graphite looks sort of brownish or a bit purpleish and a dark orange against the sky. The other two both look black on a white background but the mix has a dark red tinge lit from behind.

They are more reddish than I hoped. I was assuming the orange would be more yellowy and the graphite would be a very dark blue rather than a pure 'carbon' black but the dye when very much diluted has a Ribena tinge.

I will try again with a mix of much less orange but I  suspect it needs yellow. That is if I can find some more rail joiners!

[Alan Feldon]

sorry Ian and Andy I dont understand . My method would leave an expansion gap for hot exhibition halls etc . -your method wouldn't as this would be filled with a nylon joiner !
Alan

[andy1878]

If your track is nailed down why would it move ? I never use insulated joiners  , merely leaving a gap with no problems .
Alan

Alan
Must have miss-understood what you mean. By nailed down I took it to mean fixed solid. ie a rail is soldered to pins in the baseboard, thus both ends of the rail are fixed in place.

In plastic sleepered track the rails are free to move along the chairs, thus giving generally linear movement closing slightly any gaps, so yes that'll work  - until two rail ends, in separate sections touch. Insulated rail joiners mitigate this. I would still include expansion gaps at metal rail joiners on longer runs

In my case the two ends of the track were fixed solid (to Copper clad sleepers pinned to the baseboard) The expansion caused the track to snake, quite significantly.

[Ian McAulay]

sorry Ian and Andy I dont understand . My method would leave an expansion gap for hot exhibition halls etc . -your method wouldn't as this would be filled with a nylon joiner !
Alan

That would be true if every joiner was an insulating one, but if there are enough non-insulating ones with gaps, the rail ends should never hit each other.

[Graeme Dunbar]

Even then it does not necessarily mean the end of the rail has to butt hard up against the insulating web in the joiner that separates the two rail ends. There can still be a small gap, though the additional thickness of the web may limit how big it is sensible to make it.

From memory I think I worked it out that the maximum likely expansion for a length of flexitrack was about 0.5 mm over a temperature change of something like 30 degrees C.

[Ian McAulay]

Matters arising from discussion so far:

Dyeing rail joiners:

Following discussion at the ScOONs Zoom meeting last week, Graeme and I are going to carry out some more experiments. We will report back here.

Expansion:

I looked up the thermal expansion coefficient for nickel silver and found several values ranging from 16.2 to 19.2 parts per million per degree celsius. (Probably different compositions of nickel silver and the coefficient also seems to depend on the temperature range over which it is measured. This is also beyond my understanding of metallurgy!)

Let's take a generous 20 (to make the sums easier) and see where that takes us. The temperature an exhibition layout is exposed to could plausibly range from 0C in a freezing attic to 40C in a sweltering exhibition hall. That gives us an expansion of 20x40=800 parts per million over that temperature difference. For a metre of rail, that's 800µm (microns or micro-metres) or 0.8mm. It's not a huge amount of movement to accommodate, but it's also certainly not zero.

A confounding factor is that the rail doesn't slide frictionlessly in the chairs on the sleeper base, especially after weathering and ballasting. I think my conclusion is that the gaps need to be little and often for safety.

There's probably some advice on this out there on the internet, but I haven't done any serious searching.

Ian

[Ian McAulay]

From memory I think I worked it out that the maximum likely expansion for a length of flexitrack was about 0.5 mm over a temperature change of something like 30 degrees C.

I was still typing when you posted - our figures for expansion seem to be consistent.

[Graeme Dunbar]

I've found the link I think I used as a source for cupro nickel thermal expansion.

https://www.scottprecisionwire.com/technical-data/alloy-data-sheets/copper-nickel-alloys/

[B.Meldon]

A confounding factor is that the rail doesn't slide frictionlessly in the chairs on the sleeper base, especially after weathering and ballasting. I think my conclusion is that the gaps need to be little and often for safety.

Ian

Yes I 100% agree 'little and often' is the way to go. A tiny gap at every single normal, non-insulated rail joint may well be the best way.

I have two layouts that are now over 40 years old all built with this principle in mind. They were built in an outside gararge, they are now stored in my loft railway room and have been to exhibitions in sweltering heat and freezing cold. I have had no isuses at all with expansion of the rails.

My main layout in the loft, again with track laid using this same 'little and often' aproach to expansion gaps, has never had any issues.