NSW Railway Catenary (one
modeller’s experimentation)
A proposed line
One of the original proposals for a railway to Tumbarumba,
was a connection off the Cootamundra-Tumut branch, with a line starting at
Mount Horeb. This line would go via
Adelong, and be steeply graded. The proposal
suggested that such a line be electrified, with power coming from hydro-electric
dams.
Of course, this option was dismissed, in favour of the line
from Wagga Wagga.
I have debated if I should include an article on Catenary in
my Buildingwagga blog, as the subject matter is not anything to do with the area
that I am presently modelling However, construction
of Catenary was part of my long
modelling journey, and gave me confidence in pushing my modelling boundaries
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| Loftus station in 1994 - with a Tangara 8 car train |
Why Catenary?
Whilst modelling catenary is not a requirement for modelling
many railways, modelling catenary can be restrictive on prototype, location, or
time period. In this blogpost, I hope to
demystify catenary, and provide a primer if you do wish to model it.
My own experience goes back many decades, when I travelled a
lot on Sydney’s
suburban network. Whilst waiting for
trains, I would often sketch details of
the overhead, and consider how best to reproduce it in model form. Much of this was theory, until a few years
ago, when I put theory to practice in installing the overhead on the ACT Model
Railway Society’s Sydney prototype
exhibition layout “Yendys”.
Model Catenary
During the preliminary design stages for the ACT Model
Railway Society’s exhibition layout “Yendys”, I wanted to install overhead over
the mainline running tracks. I knew that
this would be a challenge, as at this time (2002), very little information, NSW
catenary masts, or easily accessible reference sources existed.
Fortunately, things
were changing. Train Hobby produced a
series of books “Under the wires”, ARHS
NSW produced “46 Class Remembered” & “Sydney
Electric Trains”, and more lately by Bow
River Publishing “The Leeds Forge Cars” &
“End of an Era”. All of these publications
provide excellent photographic coverage, which both inspire, and instruct the
construction of NSW pattern catenary in
model form.
We have also started seeing a number of models becoming available. Whilst the Friedmont resin kit models date
from the 1970s, the first RTR models from Bergs (Red Rattler 4 car set), and
brass 46 class electric have spurred others.
To get some variety, one had a few kit makers. KeeWizz made the Tangara,
the rare 86 class kit from Ian Lindsay Models, and the S set from Hanovale just
opened the floodgates to some really high quality models. Bergs continued with offering a 4 car UBoat
set, a selection of parcel vans, double deck carriages, and a RTR S set. Casula Hobbies had double deck cars. Southern
Rail also had U boats, and a range of ready to place catenary. But it was Auscision
that really pushed the variety. The NSW 46
class, 85 class, 86 class, and VR L class for locos, interurban V class double
deck passenger sets, the NSW Tangara, and VR Tait cars have been extremely well
received, and most models are now sold-out. Wuiske models has provided catenary
masts for Queensland, and I understand that a kit of the 3 car Brisbane
Electrics was once available from them
A note about the terminology used. I hope that I am descriptive with these
notes, because I am not sure of the names used within the NSW Railways for the
various part of the Catenary system
I trust that this primer, may encourage all to give catenary
construction a go.
Where to start.
Before beginning, I
had a number of design decisions to make.
a) What
height the wire above the track
b) What
components will be used
c) How
does one connect module sections together
d) Is
the overhead to be made live
e) Will
pantographs be touching the wire whilst running
f) What
level of detail would be needed.
Given that the exhibition layout was going to take at least
3 years to build, I knew I would have some time to experiment. (in reality, the
layout was started in 2004, and finally displayed in 2010)
Whilst I had some experience with model tramway overhead,
catenary construction would pose a different set of challenges. I read quite a number of articles in magazines
(British and German), but the best guide was one produced by Sommerfeldt, which
whilst they used their own components, covered a number of different prototype
systems.
However, I also saw that the effect of Sommerfeldt, and
other manufacturers overhead wire was one that looked chunky, and lacked the
graceful, if near invisible nature of the prototype.
As Sommerfeldt also made a number of “H” beam masts, similar
to those used in Sydney,
I acquired a dozen masts for
experimentation. In addition, I bought a large diameter roll of 300’ of 26 gauge
phosphor bronze wire, and a Lima
unmotored South African Blue train electric locomotive.
Gather information
A major step is to gather information:- plans, lots of photographs,
and guidebooks. For the Sydney catenary,
we have been blessed with some great publications, which I have listed below. Of course, I also had taken a lot of my own
pictures.
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Allawah in 1994. The new catenary masts had been installed on the platform, but the earlier masts style was still in use
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| Allawah again in 1999. New masts now in use. The earlier brick buildings on the platform had now been replaced with steel and glass shelters. |
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| Allawah in 2004. The main station had been upgraded with lifts for disabled access to the platforms. Note the way the catenary is squeezed under the building - and effect that I wanted for Yendys |
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Kembla Grange - simple modern style mast. Note the chain support for the arm, and the double contact wire. The earlier NSW catenary only had one contact wire
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| Kembla Grange - showing the wire tensioning details |
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| Single track mast - using a lot of chain supports |
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| Another single track mast - the concrete base, and "H" beam is evident. |
Mast modification
The Sommerfeldt mast is correct for German prototype but
apart from the actual mast, and concrete base, it looked nothing like the
Sydney pattern. So I removed everything
german. I then drilled holes for the contact
wire pulloff, the support bracket, and the chain.
Bend up the support bracket wire, remembering to fit the
insulator above the loop. The chain can
then be fitted, and the pulloff wire, suitably bent, with insulator.
The pictures below show this procedure with a Sommerfeldt German
prototype mast
The test track
–or- your first attempt at catenary.
The first task was to
construct a height jig. I chose a
contact wire height of 7cm above rail height.
NSW standards show that it is closer to 6.3cm, but by keeping the wire
higher, it should be possible to fix the pantograph height of models at the
right height, and still maintain a gap, to prevent pantographs from fouling, or
getting caught in the wire. It might also be suitable for some of the larger USA
models that club members may try to run. (as a note, it is difficult to tell this ruse
from normal viewing angles, and distances).
But I am getting ahead of myself.
Taking a length of old track, I affixed a short length to
some wood. Holes were then drilled for the
masts into the wood at a consistent distance from the track centreline. The distance between masts was also around
40cm, this seemed to be a reasonable distance.
Without modifying the masts, I screwed them into the wood, and secured them
with the supplied nut.
The first wire to be run is the catenary, or messenger wire,
which forms the graceful curve typical of catenaries everywhere. It fits in the upper loops of the supports
off the masts. This wire could possibly
be correctly formed off the large diameter roll if one was good enough, but for
my purposes, I weighted this wire down with wooden clothes pegs, which gave
approximately the right shape.
The contact wire fits below the catenary wire. Unfortunately, the slight curve of the wire
from the roll is not ideal for this next step, and some method of straightening
it would be desirable. As my experiments
were unsuccessful, I finally fixed one end to something solid, and kept this wire under tension during the
installation. The results of my fudge
worked to some extent, but I am the first who would say that this is not ideal.
(After I installed all the catenary on the layout with this
method, I read of a method that used fine piano wire, and silver soldering for
the contact wire.
I soldered a “L” shaped piece of phosphor bronze to the
contact wire, and positioning the jig underneath at the right height, the top
of the “L” shape droppers was soldered to the messenger wire. Note, the “L” shape droppers extends above
the messenger wire by some distance, as this allows height adjustment once the
majority of the “L” shapes had been soldered between the 2 main wires. During installation on the club layout, I
found that one could tack the “L” shapes in place at quite long distances, and
come back later to install the extra “L” shapes in the spaces skipped or missed.
Once the contact wire had been soldered to all the “L” shape
droppers, it is time to test the wire height with the jig, and locomotive if
one has one. Make any adjustments with
the soldering iron, and once happy, trim off the excess length of the “L”
shapes.
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| Take the Sommerfeldt german oattern mast (Left), and remove all the arms, leaving just a mast and concrete base |
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| Fabricate new parts. The chain is fine twisted copper wire. Add these to the mast, soldering the parts. Note you might have to drill out the existing hole in the Sommerfeldt mast |
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| Continuing to make the contact wire pulloff. The RHS picture shows the final result |
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| I made a test bed with 3 masts (3rd mast out of picture). Stringing the phosphor-bronze wire was to start with the catenary, bending as appropriate, and follow up with the contact wire which is soldered with droppers. |
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| 4 track mast at Kogorah. The modern style has each contact wire supported with their own descender brackets |
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| V set interurban approaches Springfield in the Blue Mountains. The older mast behind the newer mast has yet to be removed |
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| Ballasting at Strathfield. The older catenary, and masts have more of a lacy look than the current style. Note the pulloffs are attached to wires only. This is the effect I wanted for Yendys |
Installation on
the layout “Yendys”
Unfortunately, I did not take nearly enough photos of the Yendys
during my catenary installation, so I will describe the process.
1)
After the benchwork had been built, the trackwork
was surveyed for appropriate mast locations.
The jig constructed earlier gave a consistent distance from the track
centreline, and the distance between masts was adjusted to fit the baseboard
size, and to get around curves.
Occassionly, (as we used opengrid construction), we did not have enough
width of plywood besides the track for the mast, so some extra plywood was
added.
2)
All mast holes were drilled VERTICALLY. This is most important. The location of the holes was then marked,
as the scenery has a habit of filling holes.
(Marking holes on the underside of the benchwork would have made finding
the holes easier)
3)
Construction of the layout then continues in the
normal fashion.
4)
Once trains are running, and the majority of
scenery is in, relocate your catenary holes, and add the “naked” masts – i.e.
after they have been stripped, and before drilling, or adding the NSW
modifications.
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| A lot is going on here. The masts are in, and the contact wire is being installed under the catenary wire. Note I have started from the #2 track - this would be harder if I had started with #1, or #3 tracks. Modified Clothes pegs being used as a "third hand". The height jig (block of timber) is visible. The loco is a south African prototype (Lima) but an unpowered dummy |
5)
Using the height gauge, mark the height for the contact wire on the
masts. Remove the masts, relocate them
to the workbench, drill holes, and modify them with the modifications as
earlier described.
6)
Reinstall
the masts, and then string the catenary wire.
I used clothes pegs to weight this wire between each mast section. Careful tensioning caused the pegs to lift
off the track, and this simulates the curve of the catenary wire between
masts. Kink the catenary wire at each
mast, and solder the wire to the mast.
7)
Once the catenary wire is there, the contact
wire should follow. Make sure this is
under tension, as we do not want it to sag.
Working your way along, solder the “L” shaped droppers onto the contact
wire, and solder these to the catenary wire.
Keep checking with the height gauge, and fix any irregularities as you
go. Occassionly, I had to retension the
catenary wire, by a mm or two, but generally this was not a major issue. (The next picture shows this)
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| The contact wire is awaiting installation on track #3. The subtle curve of the catenary wire can be appreciated from this angle |
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| Another angle from the previous picture. I haven't yet made a start on track #1 |
(Note that the L droppers extend
above the catenary wires. This is to
allow modifications in the contact wire height above the track – either up or
down.)
1)
Once the section had been wired, and adjustments
made, it was time to move onto the next section.
Note. The catenary section between masts acts like
a girder – it can be bent side to side, but fairly rigid in the vertical
plane. This is a useful trick for the
next point
2)
One of the extra challenges with an exhibition
layout, is that each section, or module of the layout has to be separate for
transportation, but able to be connected together. My method was to utilise the ability of the
phosphor bronze of the catenary to bend easily, but spring back to its original
shape. So by making one module edge
rigid, the other modules catenary could be simply unhooked, and swung back and rested
on part of the scenery (I used a lineside pole). This allows the modules to be separated,
keeps the loose wire secured, and also prevents losing the connecting wire.
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| The masts visible are on the bridge module. The wire from the station module clips into this area, but is free to separate as needed. Looks worse in the closeup, and unpainted |
3)
Once all
the wire had been installed, it was painted black, with a brush. Black helps the wire “disappear” – in reality,
Sydney’s overhead corrodes to a dark bluish-green colour
Cleaning the track.
One objection to stringing catenary is that the masts, and overhead
wires will get in the way. My advice, is
to run trains frequently, and include a track cleaning pad under a number of
wagons. But, yes, sometimes you will
need to physically clean, and your hand will impact the overhead. The advantage of metal masts, and soldered phosphor-bronze,
is that it takes a fair degree of force to break anything – the phosphor bronze
wire by its very nature is springy.
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| My Hanovale model "S" set crosses the bridge over the flooded drain. The join in the overhead between the modules can be just seen. |
A big end note.
The overhead I have constructed for “Yendys” was not designed for
continuous contact with pantographs. Not
only is it higher than the prototype, the joins between sections could snag the
pantograph’s pan, causing damage, and derailments. Also the pressure imparted by the pantograph
would distort the wire, and over time, many of the solder joins could fail, both
adding extra maintenance chores. And I
was learning as I went. For instance,
the first section that I installed was the bridge area, and I forgot the
pull-off insulators. I also stuffed up
with the occasional “pull-off” direction, in that it was on the inside of the
curve, not the outside. Still, after
around 130 hours of effort, the catenary was up, and certainly looks the part.
References
- Prototype Australian
46 Class Remembered ARHS ARHS NSW
The End of an Era Glenn
Ryan Bow River
Publishing
The Leed Forge Cars C3101-3150 R.Howarth/G.Ryan Bow River
Publishing
Locomotive Profile VR L & E class John Sargent Train
Hobby
Railway Electrification in Aust & NZ Geoffrey Churchman IPL Books
Sydney Electric Trains J.Beckhaus/S.Halgren ARHS NSW
Under The Wires – NSW 85 & 86 John Sargent Train
Hobby
Under The Wires – NSW Suburban John Sargent Train
Hobby
Under The Wires – NSW Interurban John Sargent Train
Hobby
- History
Electrification of Sydney and Suburban Railways ARHS NSW
- Modelling
Catenary for Steam Railroad Electrifications Noel
Holley NMRA 1994 Portland (Clinic Notes)
Overhead System Manual Sommerfeldt Sommerfeldt
Traction Handbook for Model Railroads Paul & Steven Mallery 2-10-4
Publications
also
Occassional modelling articles in magazines rare
Modelling material (Australian suppliers)
Sommerfeldt available
from Orient Express and All-aboard Modellbahn
Wuiske Models Queensland catenary
masts – direct from Wuiske Models
Southern Rail NSW
catenary masts and portals – direct from Southern Rail (note – insulators are
incorrect on their masts – they are for 25,000volt, not the 1500Volt Sydney
system)
Postscript. Yendys has been exhibited for 10 years,
and whilst I haven’t been involved for 9 of those years, I am pleased to say
that the overhead still performs, and looks OK, despite the rigors of the
exhibition scene.
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| A bridge makes a convenient place to secure the catenary wires on firm non prototype supports between modules that cannot be seen from normal viewing angles |
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| The flooded drain - inspired by the roadway on Bardwell Creek near Bexley Road after rain, was one was to limit the height of the modules for transportation. An empty river, or creek would not have allowed us to do this. |
However, advances in the hobby since 2010 been significant. and
the latest innovation is to print your own masts. Sometimes the hard design work has been done
for you, and you can download the files for 3D printing for a small cost. Whilst this link is for German, and Swedish
masts, they point the way to what is coming , .
https://www.cgtrader.com/3d-models?keywords=catenary
Very fine catenary wire sections can
be purchased from Sommerfeldt, or even Peco, that will save a lot of time, and
frustration in trying to make your own – with some compromises in mast
positioning, and cost to your pocket..
Until Next time
