Lift Span Bridge

[Sparky]

Great build thread!  I'm following along.

Hello Mark, thanks for following.

to continue:

Back to the bridge, I decided to focus on the more complicated part of the bridge - the lift span. I need to have this section built so I can build and position the bridge towers to suit the already made lift-span.

The first thing I did was to attach the road base, kerbing and footpath to the span base.



Then on the underside I cut trenches for inlaying wiring for the navigational beacons and for eight contact points (not yet shown).



Then I drew a full-scale template of the span framework. I am using 6 mm square Tasmanian Oak for the bridge frame. I know the bridge is a steel structure, but the timber version is both more convenient and cheaper. I used bamboo skewers for doweling the framework.



While I was building the frame I came up with a solution to the cable anchoring points to the span. I cut small fishing swivels in half and soldered them to the heads of 3 mm bolts. This should also unravel any twisting of the cable during its use.



This is just to show how the span looks on the bridge.



Then I laid the wiring into the trench work. Attached contact points made from a sort of silver-tin plate which had a bit of a spring to it.
The wiring got routed towards the vertical sections of the framework. The wires will then follow the framework towards the span hut atop of the span.



After making a continuity check of all the connections, I covered the trench work with wood putty. Sanded it down and then painted it with white acrylic undercoat.

[ACL1504]

Peter,

WOW, this is really quite the project and expertly done as well. Love the thread.

Tom

[tct855]

ACL 1504,
        I'm perplexed to why you are so impressed with Peter's amazing build.  This is the same type of building process you show to others on your daily layout A&S builds.  It's nice to see even a master builder like yourself is wowed by another master builder like Peter.

Now if we can fast forward a couple years and we all can have two master builders with tonnes of cool building pictorials to entertain and learn from.  I'm still riveted here!  Thanx Thom...

Keep building boys, keep building!

[cuse]

         Wow!


Awesome project and presentation...I feel smarter just for following along.


John

[PRR Modeler]

Amazing work.

[Janbouli]

This thread is getting better and better.

[Sparky]

Thank you Tom, tct855, John, Curt Webb, and Janbouli for your encouraging and kind words.
Hope you and other members had a wonderful Christmas Eve and Day.

to continue:
More framework was added to the top of the span. Then I drew up plans for the Hut base, balconies, and gangways to the hut. There is a caged ladder outside the bridge tower for the operator to access the hut. However, I decided to delete this detail to keep the aesthetics of the structure of the bridge clean and simple.

3 mm MDF board was used here.



Used matchsticks for the railing posts. The stepped base area is the hut floor, plus an edge for me to attach the hut walls to. The rectangular hole is for feeding the wires into the hut from under the base plate.



The top left photo shows the cable anchoring point, longitudinal bumper rollers (modified microswitch actuators), and an opto-coupler https://en.wikipedia.org/wiki/Opto-isolator for signalling the hut electronics when the span has been raised to its upper position.



Here you can see how the wires got routed to the hut. The side of the span, which has the wiring attached to the vertical beams, is not seen by the museum visitor. Once the framework gets painted, it will be even less noticeable.

[Sparky]

Made lateral bumper rollers to stop the span from swinging across the bridge.


Then added vessel traffic lights. They are centrally located on the span, and on the railing of the hut balcony.
The wiring is routed under the balcony and back up into the hut.


There are storage and service boxes on the span balconies.

Bottom photo shows them drying on my window sill.

[bagman]

Peter....


This is a very, very impressive build you are doing.


A lot of the construction from "scratch" so to speak ?


You are one clever guy. What scale is this being built in ?


Cheers
Bagman

[Sparky]

Thank you bagman for kind words.
The scale is 1/72.

[S&S RR]

Peter




Very interesting build - I love all the attention to detail.  Great thread.

[Sparky]

Thank you John for your support.

to continue:
The hut wall were made from 3 mm MDF board, 2 mm clear Perspex sheet for windows, and white card for window trims and doors.




Wishing you all a...

[Sparky]

to continue:
Added split bamboo skewers for railings, and fly screen for mesh. Started to paint the span with a home mixed, Bridge Grey oil enamel.





Found some washers that fit over the LED nav; lights. Now they look more like beacons.
Added railings for the road and footpath. Gave that a paint. Will paint road later.



To be honest, at this point of model making I felt really good on how the span turned out.

[MAP]

Your build is fascinating to watch.  The details are great.  Keep those progress photos coming!

[Jerry]

Just saw this thread.  That is some really nice work and some fine details.

Jerry