Lift Span Bridge

[Sparky]

The museum workshop did not have enough room to accommodate the display table. So it is being assembled in my lounge room.
The timber arrived and so I started building the display table and the control box.

There is a 3 mm gap across the table. This is to accommodate the boat vane and pulley system.



The control box has two doors for accessing the motors, pulley-cable system and electronics.

[deemery]

There's a new lift bridge under construction here in Portsmouth NH. 


The most recent photo is in an article about a truck that blew off a span under construction :-)  http://www.fosters.com/news/20171030/70-mph-gust-blows-truck-off-bridge


dave

[S&S RR]

Peter


I thought you may be interested in this lift bridge - it is between Houghton and Hancock across Portage Lake in Michigan's Upper Peninsula. The upper level is for vehicle traffic and the lower is for railroad traffic.

[tom.boyd.125]

Peter,
Welcome to the Forum. Looks like a neat project. Need to learn some carpentry and bridge building skills so will follow along.
Tommy

[Sparky]

There's a new lift bridge under construction here in Portsmouth NH. 
The most recent photo is in an article about a truck that blew off a span under construction :-)  http://www.fosters.com/news/20171030/70-mph-gust-blows-truck-off-bridge
dave

Thanks Dave for interesting info.
You would think that they would not work in any conditions prone to gale force winds. I am quite sure that truck will be written-off.

[Sparky]

Peter
I thought you may be interested in this lift bridge - it is between Houghton and Hancock across Portage Lake in Michigan's Upper Peninsula. The upper level is for vehicle traffic and the lower is for railroad traffic...

Great photo. If I ever build a model bridge for myself, I would build this one, because it involves all three modes of transport.
My first impression was "That bridge is very low. The railway would get flooded on a king tide." Then I re-read your post... Ah, its on a lake.

[Sparky]

Peter,
Welcome to the Forum. Looks like a neat project. Need to learn some carpentry and bridge building skills so will follow along.
Tommy

Thanks Tommy for your welcome.

[Sparky]

I had enough of wood-work for a while and decided to work on the console.

The first requirement for most electronic projects is to build its Power Supply Unit (PSU). From this point, often the PSU is used for further construction and testing.

This project will require three different voltages, 5, 12, and 24 volts. Each capable of handling 2 amps. Here is the circuit I finally settled with.



Made the circuit boards and tested well on first go.

[ACL1504]

Peter,

Just getting caught up on this thread.

First, welcome to the forum. We are very happy you joined and are sharing your project with us. wonderful stuff and I'm one of the many interested followers.

Again, welcome and great stuff on the lift bridge.

Tom

[Sparky]

Thank you Tom for your welcome and support.

to continue:

Time to start building the bridge.
First drilled and glued bamboo skewers, as doweling, for where the bridge footings go.
I could not source 32 mm dowel cheaply, so I cut and shaped the bridge footings from scrap board.
Drilling center-holes into the footings allowed me to position them accurately via the bamboo doweling. Glued all the footings to the table.



To eliminate any shadow line between footings (bridge) and table (river) I used wood putty around the edges. Hoping that when I paint the river the bridge won't look like it is floating on top of the water.

Glued the piers into place, each set has a different length, for the bridge arches across the river.



Then I attached the plywood girders. The end with a box end has a street (Bridge St) passing under the bridge. The loose board will be the base for the span.

[PRR Modeler]

Very nice work.

[adm.nelson]

Peter, that is one heck of a project. The bridge alone would be a huge undertaking, but all the electronics, well, that's where I get lost. My hat's off to you, mate. I'll be interested to see how the bridge goes together.

Tony

[Sparky]

Thank you Curt and Tony for compliments.

to continue:

I thought I better give the bridge an undercoat before applying any road base. While I was at it, I gave a few coats where the river water will be.
The holes you see along the girder edge where the span sits in, is for contact wires. These wires, eight in all, will serve the span electronically. Part of which is to provide DC power to its 9 volt rechargeable battery for when the span is being in motion (not docked). Other contact points are for signal data, such as vessel traffic lights.



Up and down stream from the bridge are several sets of Fender piers. the outer sets contain navigational lights. Their center piers have a hole drilled through them to accommodate the LED and wiring.

[Sparky]

Collected all sorts of electronic junk from friends and neighbours. Spent a week stripping down old analogue TV sets, computers, video recorders, disk drives, etc. All for the purpose of obtaining parts and components. From this, I obtained a good set of TV speakers. They will be used for the sound effects (alarm bell, boat sounds) for the diorama. However, these speakers were set in a plastic mould, and as a consequence the speaker cannot be mounted without a bracket. This is needed to keep the speaker's diaphragm from touching something (dulling the sound output).



I returned to the museum to cut out the holes, for the speakers, in the back of the console. The museum staff made the suggestion to take photographs of the console interior so the young visitors could get an idea what went into the workings of a console. I suggested to replace the front panel with a thick sheet of perspex. So now the console interior is to become a sort or wiring diorama, with interior lighting. The interior got cleaned up and painted with a dark bluish grey in the hope of contrasting the proposed coloured wiring.



Made a new set of numbers for the terminal strips, and mounted the Power Supply Unit to the side plate.

[MAP]

Great build thread!  I'm following along.