Working Bridge and Boat Diorama

[Relic]

This is my first model and diorama. It is going to be a working lift-span bridge with a boat traversing underneath it. The Ballina Naval & Maritime Museum acquired the original (1964) control console-panel for operating the Wardell Bridge. My job is to convert the console, yet using the original control panel instrumentation, to operate a scale model of the bridge. The model bridge and the electronics to operate it is being built from scratch.

There are no other plans or schematics other than what I come up with. So I collected images of the bridge. Measured with a tape the length of the span, and the width of the road. From these two diagonal references I was able to draw a plan of the bridge from the collected images.

The display area given to me, for the bridge diorama, is 2.4 x 1.2 m. A scale of 1/72 is the nearest to using up the whole length of the bridge.
Here is the actual bridge:


I do not plan to make an exact reproduction, but will make one as close to scale with readily available material. The focus will not be on replication but on operating the bridge. For example, instead of miniature steel bridge framing, I will be using 6 mm square lengths of hardwood.

The console appearance is antiquated and we have decided to keep it that way. Though it has been rust treated and satin varnished, it looks the same. However, the screws holding the panels onto the console will be replaced with new ones. The interior will be updated with new wiring and, in itself, will become a separate wiring diorama display. To do this, the front vertical panel will be replaced with a clear perspex sheet, plus interior lighting.
Here is a photo of the console and panel with a reference drawing.




I am currently half-way through the project and still have many months to go before its completion. I will endeavour to post images with descriptions so you can see, and read, what has been done so far. This may take a while to compile. When I get to my current status I'll let you know.

[Relic]

My first problem, besides building the model, is to work out how to make the bridge and boat operate.



The motors for operating the bridge span is slightly too big to fit in the span hut (where the actual motor is). I did not want the motor to be visible, so my only alternative was to have it under the display table. So now the pulley cabling has to move through the tabletop (water) and the bridge road.

The boat motor will also be under the table. It too will be operated via pulley cables. A thin slot in the table, running laterally under the bridge, will accommodate a sliding plate with the boat attached to it.

Both bridge and boat motors, with some electronics, will be housed in a box under the display table.



Below is a rough layout of how the display will look like.

[Relic]

The display area already has a steel frame for holding the table. Both the tabletop and control box has to fit on and through the frame respectively.
Here is one of my drawings which show how and where the control box will be mounted.



Below, the construction of the table and box.





You may notice that the box has two doors which swing down for access and servicing. The box section is currently separated from the table, otherwise the display would not fit through the door. It will be assembled once all the parts are ready to be transported to the museum.

[digger303]

Could you run the lifting cables under the bridge behind the girders towards land where it would be easy to hide them and the motor.

[Relic]

Could you run the lifting cables under the bridge behind the girders towards land where it would be easy to hide them and the motor.

Thanks for your thoughts and input.

To answer your question: Not really, because there is cabling at both ends of the span. One set could go under the north-bound girders to a motor, but the other set would have to go to another (synchronized) motor at the other end. This would become more complicated to manage.
Also, if I were to use only one bridge motor, under the girders, one set of cables would have to cross the path of the traversing boat. Even so, the boat motor and pulley system, to be hidden, must go under the table anyway. So I might as well have the bridge cables go there too.

The cables will be running near the end piers, and they will only be about 0.7 mm thick (enough to handle 20+ kg)... which the span should not weigh more than 1 kg. I am hoping cable thickness will be somewhat unnoticeable.

[Relic]

While building the display I am thinking about the electronics required for the job. My first task is to build a DC power supply. Three voltages are required; 24 volts for control panel lamps and all other lighting (LEDs), 12 volts for motors and relays, and 5 volts for logic circuits. I had a few problems based on the available transformer ratings. It was a tad too high for most voltage regulators. But I figured a way around it. Here is the circuit used.



and the building of the circuit.



The power supply unit will be housed in the bridge console.

[Relic]

Now for the bridge. The first thing is to make and locate the bridge footings onto the tabletop. Available dowel was too small or big and only came in long lengths. So I made my own. I used bamboo skewers as dowels for aligning and securing the footings, and later the piers.



Then came the piers. Wood putty surrounds the base of the footings to conceal any line between it and the river water (once painted).



The girders.



and an undercoat of paint.



You will notice several holes where the span will rest. These are for wiring the contact points which will supplying power and data to the span and hut. To explain, on top-centre of the span framework will be a set of vessel traffic lights (red & green). Underneath the span will be a set of navigational lights. However, as soon as the span rises it will be isolated and then it will be powered by a rechargeable battery which is in the hut.

Below, fender piers (aka dolphins) are being prepared for later installation. The outer fenders have navigational lights and their centre piers have been drilled to accommodate them.



Oops! It's time to go to work.

[Relic]

Back to some more electronics.

To operate the bridge it has to be done in a sequential way. Before the bridge can be raised the road traffic, and pedestrians, have to be stopped. Traffic lights go from green to flashing amber, for about twenty seconds, then the red stop lights come. During those twenty seconds a warning bell will be heard. This sound will be an electronic simulation.

Below is a test board I use for circuit designing. The top half, with relay and LEDs is for the flashing amber lights. The relay is used for the 20 sec delay. The bottom half is for the bell sound circuit. Once I am satisfied with the circuit operation I make a circuit drawing, a printed circuit layout, etch the circuit board, and solder the components to it.



I needed a pair of speakers for the sound effects, so I used the speakers from my old analogue TV set. However I needed to make a bracket for them. For this I used 3 mm MDF board and some vinyl mesh.



Holes needed to be cut out of the console to accommodate the speakers, power socket, and cable connector sockets (between console and control box under the tabletop).



Since the console interior will be a diorama too it needed a coat of paint. I decided to use a dark water blue colour to contrast the brighter colours of the interior wiring.



I decided to add some lighting to the power supply circuitry by adding a 'blown fuse indicator' circuit. While the DC voltage outputs are okay, a green LED for each of the three voltages will be lit. As soon as any of the voltages experience an overload its fuse will blow, which in turn extinguishes its green LED and its red LED lights up - to indicate that its fuse has blown.



Below, the three terminal strips got cleaned up and new numbers (0-60) added to the terminals. The power supply board is attached and hooked up to the terminal strip.

[Relic]

I searched everywhere for some slim pulley wheels, especially for the top of the bridge towers. Unfortunately none suited the job, so I had to make my own. I decided to use washers. I knew that if I sweat soldered them together nothing, short of extreme heat, could pull them apart. After a trial run I was able to determine the amount of soldering wire needed between each washer. I greased the bolt and placed the washers and solder to make a sandwich of sort. The gas torch heated it all up and the washers collapsed together as the solder melted. I think they turned out okay.

[Fridgy]

Um.... . What to say besides wow!

[Twokidsnosleep]

Wow indeed, very impressive
There are styrene 'steel' beams made for train modelling bridges...you might be past that need already but I can pop up a pic if you want
You should put down your country of origin so we can be of more help

[Relic]

Thanks Mick and Scott for your kind words.

Thanks Scott for the input and heads-up, Australia it is.

I did not know about the plastic girders. I found this web page http://hobby.uk.com/materials/plastic/s ... beams.html, they look good, but as you said, I have already passed that need. Know I know they can be bought.

[Relic]

Now for the bridge span. This is a complete project in itself. I had already glued Masonite sheets, onto the span board, for a road and footpath base. Under the span are a set of navigational lights (red and green LEDs), and contact points for the electrics.

I still use a mallet and chisels. Due to impact, I needed to cut channels to accommodate the LEDs and wiring, before adding framework to the span.



On the Internet I saw how modellers used a paper template for making framework. I did the same. I used 6 mm square Tasmanian Oak.



Then I decided to make the cable anchoring points - in preparation for later installment. The placement of the span gangway (to the hut) depended on size and placement of these anchor points.
I used fishing swivels and 1/8 (3mm) bolts. I filed flat the bolt heads and the edges of the cut swivels. Solder coated the heads and then soldered the swivels onto them. They are quite strong.



I continued with the framework. After gluing the struts together I used bamboo skewers for doweling the joints. However I stopped short of completing the top because I needed to finish the span bottom before adding a bridge control hut and gangway - to make the job easier.



to be continued...

[Twokidsnosleep]

Yes I-beams, but also girders


They do build up nice


In a pinch, maybe to dress up a side railing or something without going all scratchbuild

[Relic]

Thanks Scott. Good idea.

The framework of 6 mm is equivalent to 1.5 feet square in 1/72 scale. It is already slightly too thick. Adding to it will make it look too bulky and/or the bridge length too short. However, I will definitely use the prefab plastic steel framing in future projects. Thanks for the tip.

Just to let you know, the museum which I volunteer for, pays for the material. It is a non-profit org; and is limited with its funding. So I try to cut corners where I can. So with a mixture of ready available material, and ignorance on my part, I will inevitably miss out on some better deals.

An example of me cutting corners, last month I ordered some model trees, but soon realized that I will need many more. After a closer look at them I knew I can make my own (maybe not the foliage). So over the last few days I've been making trees from all that scrap wiring from the original console.

Here is my first three trees. Number (3) is 200 mm (about 50 feet to scale 1/72). They actually take awhile to make. I will be focusing more on thickening the trunks on my next ones.

[Relic]

Back to the span. It was time to finish off the span undercarriage before building the span hut and gangways.
I used thin shim steel for the contacts to ensure all 8 terminals will make contact when span rests on the bridge.
Bottom centre shows all 8 (4 x 2) wires, for the LEDs, converge and soldered to make 5 (4 + and 1 earth) wires.
The wires will eventually be made to follow the framework to the span hut.



After testing the LEDs and contacts were all working I filled the channels with wood putty. After sanding, I applied some acrylic undercoat.

[Relic]

The span hut and gangway floor is made from 3 mm MDF board. Below shows my plan for the base plate and gangways. There is a small on either side of the span. They are part of the balconies. All those little sluts, on the drawing, are for securing matchstick railing posts.



On the right, you can see that the anchoring points have now been installed. They had to be located with having knowledge of where the pulley wheels will be on the towers. Also a hut floor plate has been added to the base. Its edge will both govern and secure the hut walls into place. The rectangular hole is for allowing the wires to enter the hut from underneath.



Before going to much further, I decided to add the extras before it got too cramped from the gangways. Besides the anchoring points there are longitudinal bumper rollers fitted. These will guide the span lengthwise so as to avoid the span from catching onto the bridge tower. The rollers are modified from actuator levers for micro-switches (I was able to get a bag of ten - dirt cheap).

That black U-shape device is a slotted optocoupler (light beam switch). This is used for the vessel traffic lights on the span. Once the span reaches the top a 'blind' will pass between the (U) and trigger the green 'go' LED, and turn off the red 'stop' LED.



The next step was to route all the wiring to and through the hut floor.



By now I worked out how to make the lateral (sideways) bumper rollers. I used some 6 mm timber and used a pencil sharpener to cone the ends. Then attached the rollers to the ends via a nail (glued). I simple doweled them in. It sure looks cramped at the corners.

[Relic]

My next job was to add the vessel traffic lights. I used the same LED indicators for the 'blown fuse indicators'. I routed the wires down and up through the hut floor (it looked better that way).



Below is my plan for the hut floor and where several boxed like structures are located. These boxes housed certain bridge equipment such as an auxiliary generator, tools, etc. The bottom picture shows the boxes (blocks of wood) painted and waiting to dry.



Building the hut. The windows are thin clear perspex. The window frame and doors is white card.



After finishing the railings I added fly-screen wire (plastic) for mesh.



Painted the span from framework up. The top left picture, on the laptop, shows what the span hut really looks like.



Below, the undercarriage got painted. I found some thin washers that fitted over the navigational LEDs perfectly. Now the look like lamp bezels.
I added railings (matchsticks and split bamboo skewer) for both sides of the road and footpath. And a touch of paint.



to be continued ...

[Relic]

Now for the bridge towers.



Over 11 metres of 6 mm square timber went into building the towers.



Time for mounting the pulley wheels on top of the towers.
The brackets were made from sheet aluminium. Top-centre picture shows an old school method of drilling a smooth hole into thin metal.
For those that don't know: Place sheet metal on top of scrap wood. Drill a small pilot hole, then place a folded rag between the pilot hole and the drill. When drilling, the rag and wood fills the drill fluting to stop the drill from wobbling around.



Assembling the brackets.



The bottom picture only has the towers resting on the bridge. I was seeing how the wheels align with the anchoring points. They were spot on.



Below, I was just seeing how much clearance there was between the bumper rollers and the towers.

[Relic]

There is a servicing gangway around the pulley wheel brackets.



The gangway follows a similar design to those used around the span hut.



And now painted.

[Relic]

Before I could mount the towers onto the bridge a few preparatory tasks were needed. Firstly I needed four sets of traffic lights to be built, The road surface, gutters and footpath assembled but not yet attached to the bridge girders. Both the traffic lights and the span wiring had to be laid down along the girders for the span and under the road for the traffic lights. Once all is prepared the road can be attached to the bridge. Then the towers can be attached through the road to the girders.

I used 5 mm LEDs for the traffic lights, because the 3 mm LEDs looked too small. However, they look bigger than they are. I used them anyway.
Top left picture shows my first few attempts failed. Finally I got the right approach. The outside walls, of the housing, is made from card. This will allow easy access if I need to do any repairs.



During this stage of modelling I realized, that once the towers are in place, the span would not be able to be removed for servicing. The bumper rollers and the pulley wheels restrict removal of the span. The only way out was to exchange two of the fixed lateral bumper rollers for removable ones. Now the span can be removed laterally (sideways).



Below are pictures of assembling the road, traffic lights, wiring, and finally attaching the towers into its straight and aligned position. It took most of the day to mortise, align and secure the tower exactly where it supposed to be.

[Relic]

Now it was time to add the railings along the road and footpath. I split about 50 bamboo skewers to get about 35 good railings. Because the road is curved I had to use a square to align the matchstick posts to the tabletop surface. The gap you see near the traffic lights is for the swing gates.



This is my last post to where I am currently at.

To be continued.

[Relic]

This is my first model and diorama...

Today I just realized that the above statement is not true . Sorry about that, it slipped my mind. I had a senior moment.
This bridge is my second model. The first model was done 26 years ago. It was a scratch build working model, 1/10 scale, of a Tesla coil built by Nikola Tesla in Colorado Springs in (1899).
https://en.wikipedia.org/wiki/Tesla_Exp ... al_Station

I no longer have this model, it was lost in a house fire, but I do have some photos of its construction.
I hope it's okay to post these in another "Everything else" thread.

[digger303]

Did you burn the house down

[Relic]

Did you burn the house down

No I did not.
We were away at the time, and a teenager who knew we had a .22 rifle for pest control, broke in and stole it. He wanted to shoot a neighbour with it, because the neighbour would not allow his daughter to see this teenager. However, before leaving our place, he decided to burn the house down to rid of any finger-prints. He got caught after the neighbour called the police.

[Fridgy]

Before or after shooting said neighbor??

[Relic]

Nobody got shot.

[digger303]

do you normally hit what you aim at

[Relic]

do you normally hit what you aim at

Ha ha ha
23/25 kills from 25-300 m with 5 rounds per 5 body positions. And I still missed out of the RAAF target shooting team.

[digger303]

Maybe the .22 too small for ya

[digger303]

But shame you just missed the team

[Relic]

Maybe the .22 too small for ya
But shame you just missed the team.

The teenager held off the police for awhile before being apprehended. Later his parents were bragging how he was a hero of sorts like Ned Kelly. They too had no feelings about burning our place down. Some people!
Anyway enough of that. In a few days I will be uploading an update of the model bridge.

[digger303]

look forward to it.

[Relic]

Finally painted the bridge railings.



The cement bridge and concrete road is to be painted next.
I don't think I will show weathering. It's against my schooling, in architectural rendering, to show polluted buildings. Especially when it is a show piece for a museum owned by the shire council.

[Relic]

After three coats of paint I finally got a good flat matt paint job for the cement parts. The concrete road will be painted next.

[privatepete]

Hi just a quick question is this you young man.


Peter
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First Name:Peter

[Relic]

Hi just a quick question is this you young man.

Yep. I am trying to get as much help as I can; and as much awareness, without pushing it, about the museum.

Anyway, I finished painting the concrete part of the road, minus the white traffic lines, and other small bits.
At first it was an experiment that blow up in my face. The splattering got blotchy by overdoing it at places.
Then I tried to fix it up with some dry brush work. Used dark paint on the lighter areas and visa versa.
Then with a fine brush, using the same approach, got the different shades into finer dots to blend it all in.
I think it looks more like a concrete road now.

[SergioSolo]

Wow! You certainly fix it

[Relic]

Thank you SergioSolo.

I am still working on the road section within the bridge span. It's a bit tricky, especially putting in the white fog lines.
But as soon as I complete it, I'll send in some photos.

[Relic]

Finally completed the road.
The bottom pictures is just me fooling around with some 1/72 scale cars I will install at end of project.

[Relic]

Cleaned up and painted parts of the console.


Revamped the Control Panel.

[Relic]

Looks like I am a relic.
I know I have been away for awhile. Things get in the way, especially health issues.
Is anybody interested in this project anymore?

[BobM]

Looks like I am a relic.
I know I have been away for awhile. Things get in the way, especially health issues.
Is anybody interested in this project anymore?

Absolutely. Not that I would attempt anything this complex, but it is a great inspiration.

Yes, life has a way of being difficult at times. I hope that whatever it was, the worst is behind you and that you are able to enjoy the holiday season...

[Relic]

Thank you Bob M for your interest and well wishes.

To continue with the project, the console needed rewiring, particularly having the necessary wires from the various switches and panel lamps to the three terminal strips. I never done a wire harness bigger than what you might find in an old transistor amplifier. This required a completely different approach than one done in situ. I discovered several sites which showed how they make harnesses for automobiles and such. They use a board with anchoring points to create an measured out harness map. So I decided to do the same. It took longer than I thought to complete this.





Then I I attached the top half to the underside of the control panel. There is close to fifty wires going to various parts. It is not as neet as I would have liked it, but nobody is going to see the underside unless they look up into it (through the perspex front panel).

[Relic]

Then I placed the whole control panel onto the console and then attached the bottom half of the wiring harness to the three terminal strips.
In a way I was pleasantly surprised how well the harness terminals were easily aligned and installed.



Now the opposite terminal, of the three strips, needed to be wired also. Most of which were routed to the two 25 pin D-connectors at the rear of the console. These feed power and data to the control box under the display table (via cabling, I think. Not yet decided).

[Relic]

Added a Passive Infrared (PIR) sensor to the interior of the console.
This will activate the display whenever someone walks near it, and nobody else is operating the display.
The PIR had to be above the kick-board, so I made a slanted bracket to follow the lean of the front panel area.



Then I added some grey dyed felt around the edges of the console. This is to seal the perspex sheet from dust etc.






And by the way.

[aur0ra145]

This is seriously cool. Glad it's coming along well!

[Relic]

Thank you aur0ra145 for your support.
____________________________________________
Drilled holes in the thick Perspex, allowing heatwaves to reach the PIR sensor. A portion of the front panel was used as a kick board to protect the Perspex.

[Relic]

The PIR sensors movement in its vicinity. When it does it will turn the console lighting on. The only times it turns off is when the PIR no longer sensors movement for 10 seconds, or when someone starts working the console.

[DrSprue]

Wow, I just read your entire posts (yes all 5) and I have to say what a cool modeler you are and an outstanding Technician. Just awesome work on this bridge dio. Your museum must be very proud of what you are doing.