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Wardell Bridge and boat by Tecko - Small - 1:72

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To be honest, the boat in this diorama will be built near the end of the project.

The diorama is going to be a working lift-span bridge with a boat traversing underneath it.

The bridge fits on a 2.4 x 1.2 m (8 x 4 ft) tabletop. The scale is 1/72.

There are no available plans for the bridge. Created my own plans from photographs and two diagonal reference measurements (road width and span length).

An antiquated control console of the actual bridge will be converted to operate the model. Created my own electronics for the diorama.

I am a volunteer for the Ballina Naval & Maritime Museum. They are funding the material costs.

The diorama will be an interactive display for the museum.


This is my second model I have ever built. The first was done 26 years ago. It was a 1/10 scale working Tesla coil used in Colorado Springs in 1899.

The current model is halfway to completion.

My task is not to make an exact reproduction, but a close simile. Available materials limit the accuracy, but I endeavour to do what I can.


The boat is not following any plan other than my own. It has to look symmetrical because the boat only travels along a straight line under the bridge forward and back.

Seventy percent of the project will not be directly related to the boat.

I have considered the Shore Leave forum but felt that it would get in the way of all those fun threads and other non-modelling topics.


So I hope you all don't mind me being here.


The model is based on this bridge located at Wardell, NSW, Australia.


The display area for the diorama will be something like this..


There are quite a few photographs to upload - to catch up to where I am currently at.

When I do catch up I'll let you know in the post.


to be continued.

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Thanks Patrick and Keith. I hope not to disappoint. 


To start of with, I thought it would be good to share know what is inside one of these consoles.

The plan is to keep the exterior looking as is - antiquated (rust treated and satin varnished). However, the interior will be spruced up and visible through a perspex front panel. The interior will become a lit wiring diorama - an added treat for the museum visitors.


Below includes a drawing of the panel layout


The control panel components will be used for controlling homemade electronics for the model. However, I needed to know what each control component was used for.

I soon discovered that there is a purposeful sequence of events to raising and lowering a lift-span of the bridge.

For quick insight...

  1. Bridge navigational lights must be on. Vessel traffic lights for both up and down stream are red. 
  2. Road traffic lights are switched over from green to flashing amber lights for a delay of 20 seconds, and can be delay longer if necessary. During this time an alarm bell is sounded. The bridge operator, in span hut, looks through an inverted periscope to check that no cars or people are between the two set of traffic lights.
  3. Traffic lights go from amber to red.
  4. Four gates close across the road.
  5. Span lock is disengaged.
  6. Span is raised all the way to the top of bridge towers.
  7. If vessel is upstream then its traffic light switches from red to green.
  8. After boat passes under bridge, both vessel traffic lights are red again.
  9. The bridge lowers about 60% of the way, then it gets inched down in four stages. The last stage is fairly close to road base.
  10. Span gets locked again.
  11. Gates are opened, Then road traffic lights turn to green.

My task is not only have the control panel operate as mentioned, but to also make it childproof. In other words, a switch cannot work unless it's turn in sequence is for it to work. This is so, for example, the span cannot be lowered onto the traversing boat. This bit has not yet been fully worked out. It's a bit of a headache for this out-of-date technician. But I know I will have the logic circuitry worked out.


Below, the console has been opened for examination. It was built around 1962 and those two large rotating switches are custom made for the task.

I took all looses wires out to make access to wiring harness for further eaxamination. Eventually I took the whole console apart. It needed a complete rewiring.


Next is the display table.

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My goal is to create something like this.


The boat and bridge motors will be under the display table - in a control box. Both will be moved via cable and pulleys.


The tabletop.



Yes, my lounge is my studio-workshop. The museum did not have enough workshop room for this display.


The control box to be aligned directly under the tabletop slot for the boat pathway.

It has two access doors.


Next is the bridge substructure.

Edited by Tecko
Motor cabling diagram needed to be amended.
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The bridge footings. I used bamboo skewers for doweling. The footings 

I do not have access to a lathe, or round stock of near size. So it's just good old fashioned hard labour for a pirate (cut and file). Arg!


The piers


The girders


And an undercoat.


Above, you may notice some holes in pier ends. These are for electrical contact points for bridge span. The span will have a rechargeable battery to power its vessel traffic lights. Battery gets recharged while docked onto road base.


Fender piers (aka Dolphins). The outer centre piers have a hole through them for installing the navigational lights (small 3mm LEDs).


Next is some electronics

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Keith, I am glad you are enjoying this side-track.

I too did some googling about control panels for nuclear reprocessing plants. It looks similar but 100 times the instrumentation :stunned:. I am glad a lift bridge is not so complicated. 


Electronically, this project requires both analogue and digital components. Three voltages will be required; 24 volts for panel lamps and LEDs, 12 volts for relays and motors, and five volts for digital circuitry. I created a spare vacancy, on the circuit boards, for any future requirements. So my first task is to build a Power Supply Unit (PSU) to fit into the console. 


Side note: part of such a build for a museum is to put together an operating and service manual. Any drawings and diagrams you see in this thread will be part of that manual.

The circuit diagram.



Since the console will also be a diorama, I added visible LED 'blown fuse indicators' for the DC outputs.


There will be certain sound effects added to the diorama, such as the alarm bell, boat fog horn, and diesel engine for boat.

I needed some speakers so I cannibalized my analogue TV set. However they needed a spacer-bracket for speaker diaphragm clearance. 


Holes cut for connectors, power socket and speakers (not seen here).


Interior of console painted a Boatshed Grey, as a background, in hope of contrasting the wiring harness when installed.



Next is the bridge span.

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Before building the span framework I decided to use mallet and chisel to entrench the wiring for both navigational lights and contacts.


Then added some of the framework so I could see where the wiring needs to go.


Then I got an idea for making the cable anchoring points on the span. I attached part of a fishing swivel to the small bolt heads. These will untwist any rotary tensions on the cables.


Just to see how it looks compared to my drawing.


It was about at this point I went around all the joints and added 3 mm dowels for added strength.

Below, I installing the wiring, tested all connections and made a map before covering it all up with wood putty.



to be continued... time to do some work.


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4 hours ago, KeithAug said:

How long did all that lot take? Moving along very well and very fast.

Hi Keith. I started late last year. This is the fifth month. I am only doing it on my spare time. The museum gives no deadline to volunteer workers, so I can go at my own pace. Currently about halfway. More photographs are yet to come before I catch up to where I am at.

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2 hours ago, Omega1234 said:

...The bridge is coming along beautifully, but the wiring...OMG, I'd get totally lost...

Thanks Patrick.

But as we modelers know, we just worry about the step we are on, step by step, and let the results take care of itself. 

Besides, I always make a mud-map so as to not get lost. But keeping track, of what does what, gets harder to retain as age creeps in. :unsure:

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Next is the span hut, gangways and other bits.

The base plate and gangway paths.


Used matchsticks for railing posts.

The anchoring points have been installed. The rectangular hole in base plate is for feeding the wires into the hut. The floor plate on the base is for securing the walls.


TOP L-R:  Next to anchoring points is a bumper roller for guiding the span and eliminating any snags while span is in motion. I used micro-switch actuator arms for the rollers.

The black U-shape bit is a light switch which gets triggered when a blind passes in between. This happens when the span reaches the top of the bridge towers. Then the red vessel traffic lights change over to green.


Gangway posts are installed. The wiring has been routed to and through hut floor.


to be continued...


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Now the span needed another set of bumper rollers for lateral movement.


The vessel traffic lights, positioned at top centre of span.


Around the hut, on the balcony, are four containers storing auxiliary equipment.


Fabricating the hut walls using 3 mm MDF board, 2 mm perspex for windows, and white illustration board for window frames and doors.


Gangway railings. used matchsticks, skewers, and fly-screen.


Painting the span. Laptop screen shows image of actual hut.


Installed road and footpath railings (matchsticks and split skewers), and painted them.

Found narrow washers that fit the navigational lights (LEDs) perfectly. Now they look like beacons.


Next is the bridge towers.

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Hello Andy.


Yes I am hoping it will be a fun interactive display. But I think it will, at least in the beginning, need to be supervised. Some may become too impatient to follow the operating procedures from start to finish. If it got abandoned halfway through, a museum worker will have to rested the switches.


Would not be able to ride counterweight here in Australia, not these days.


If you are referring to the Carlton Bridge it sure is a nice looking bridge. Pity it recently had problems and possibly facing closure. Do you know anything more about it?


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Thank you all who have registered 'likes' to the above posts.

It is far nicer than getting a pat-on-the-back from Hook. ;)


Below, the bridge towers are being built.


All the corners are doweled, using 3 mm bamboo skewers. By the way, the bridge timber is 6 mm square Tasmanian Oak.


Now for the bridge pulley wheels. I could not find any pulleys large and narrow enough to my liking. So I decided to make my own by sweat soldering washers together.

My first attempt used too much soldering wire, but got it right after that. I needed ten pulley wheels.


Then designed and built four pulley brackets to suit the tower frame.




Note, the towers are not yet installed. I have to put in the road before securing the towers.


Below I am just checking clearance around the bumper rollers.

As it turned out, after installing the towers, I had to extend the longitudinal rollers a 1-2 more millimetres.


Now for a servicing gangway around the tower pulley wheels.




I seem to like the raw look better.


Next is the combination of traffic lights, wiring, and road before installing the towers.


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The only tri-LED indicators I could find used small LEDs which were too far apart from each other, and did not look like traffic lights.

Decided to make my own from 5 mm LEDs and set them close to each other. They look better, but they are bigger in scale.

I think they will look okay, and visible, for this diorama.


My first efforts fell apart, but then found the right approach.


As you know, while doing a repeated job, the mind starts going over what is, what will, and what if. It was on such an occasion I realized that once the span is in place it could not be removed for servicing. Both the bumper rollers and tower pulley wheels restrict removal. To solve this, I decided to replace two lateral bumper rollers with a set of detachable roller arms. Now the span can be removed laterally (sideways).


Now for the tricky part. Installing the towers.

First the road and footpath needs to be built and drilled for railing posts. Wiring along girders need to be routed through the tabletop. Road to be secured by glue and doweling to girders. Notches cut through road for tower legs. Align towers straight and in line where the cable moves between pulleys and holes through the road and tabletop. Once aligned, I glued and doweled the legs into place.

There is not much strain on the cables. The span is about 1 kg. The cable is 0.7 mm and can hold 20 kg.

Also the counterweights are not needed because I will be relying on the span weight for it to be lowered. Instead I will use a block of balsa for the cement counterweights.


Now to tidy up the wiring under the tabletop. All wires are harnessed into the control box underneath ... when I install the box at the museum. But first the diorama needs to be completed, at my place, first.


Next is the bridge railing and some painting.


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Installing the bridge railings. The gaps seen near the traffic lights is for the swing gates that block the road traffic.


Painted the railings and the cement parts. The road is concrete (cement with gravel) and will be my next job.



That's it so far.

Will be posting updates as I reach certain milestones.


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1 hour ago, KeithAug said:

...Its wonderful how the lack of a lathe stimulates ingenuity.

Hello Keith. Thanks.


To be honest, that is what I truly love about being creative.

Ingenuity is like a spark of hope that something new or different will save the day.

It brings wonder, insight, and joy in the heart after it has been applied with good results.

I believe every modeler experiences it.


I also believe scratch building provides greater opportunity for both ingenuity and headaches.

It's amazing how a spark of ingenuity can consume a headache.

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Started to paint the concrete road.


My plan was to splatter the cement surface with darker grey. But the plastic bristle brush soon got softer from the oil paint and became difficult to aim the splattering. I ended up over-doing it in many places. I thought this was a stuff-up and might have to start again. But first I will try to work with it, and if that fails then I'll start again.


BOTTOM L-R: At first it was going well, then up the road it went sour.


So I dry brushed cement grey over the dark, and some dark over the lighter parts.

Then went over the road with a fine paintbrush and added dots of dark into the light, and light onto the dark.


LEFT: Is after a rough evening-out by point work.

RIGHT: Is after another point work coverage but this time I stepped back to see the lighter and darker patches that needed further blending.


I think it turned out okay. :Whew:

I feel confident that once the road has the added double-centred lines, and outer fog lines, it will look more like a concrete road.


Oh, by the way, I have not done the road in the span yet. Hmmm, another challenge. :huh:



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Day off from the bridge. I am waiting for the paint to dry before further work. So, in the meantime, I've been figuring out what a simple symmetrical boat would look like.

It has to be small enough to seem distant from the bridge before and after steaming under it.

It must also be tall enough to warrant the span to be raised to full height.


Below is my plan. Please feel free to make any suggestions that may help it to look more real, yet simple.



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