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Lattice Girder Deck Truss Bridge - Kit bashing


zr2498
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45 minutes ago, LNERGE said:

Puts my attempt to shame... Some photo's of the real one too.. Click on the picture and it will take you to a Flickr album. Pictures taken during an engineering block.

 

Br1550 Chesterton Junction.

 

It will be interesting to see how your bridge progresses. Can't really see the sectional detail with just the one side on photo. Thanks very much for the link to the Chesterton 1550 Junction bridge photos. Really useful detailing information. It seems nearly every bridge design in the past used to be different, until BR attempted to standardise them.  

Many of the gusset plates you have cut out may be produced by Central Valley Model Works in the near future. As well as the already available girder sections, Jeff at CVMW said he was working on new sprues with selections of gusset plates. Really useful for scratch builders.

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55 minutes ago, zr2498 said:

It will be interesting to see how your bridge progresses. Can't really see the sectional detail with just the one side on photo. Thanks very much for the link to the Chesterton 1550 Junction bridge photos. Really useful detailing information. It seems nearly every bridge design in the past used to be different, until BR attempted to standardise them.  

Many of the gusset plates you have cut out may be produced by Central Valley Model Works in the near future. As well as the already available girder sections, Jeff at CVMW said he was working on new sprues with selections of gusset plates. Really useful for scratch builders.

That’s my point. My side is finished and on the layout. There is no rivet detail when there really should be. It is hiding an almost impossible span and is an attempt to show a bridge of different design to the main line as it was made at a different time/company. Yours is inspirational for sure and especially the mention of parts to help. 

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A little more progress:

The upper parts of the cross bracing gusset assemblies have been added to the truss frames

Trying to replicate these on the Findhorn viaduct

 

 

903051100_Crossbeamgussetts1.png.86ffea724ead92ceff41c0f3ebe97a11.png

 

or these on the Forth bridge

 

 

608006807_Crossbeamgussetts2.png.ac160f68bc465eb5e088e5ef5fb86dee.png

 

 

DSC06148.JPG.6a2a9fdb6022893c60be19d69afcd4c0.JPG

 

The cross bracing at the bottom of the truss frames will be made up of some straight and some diagonals lattice beams. They will be a modified version of these on the CVMW single track truss bridge sprues

 

 

DSC06156.JPG.096580bcd93d80f9041f5df9ebb51c57.JPG

 

All of these will need to be shortened. The straight pieces are complete and a mock up of a typical position is shown below.

 

DSC06168.JPG.e79492fba59c67044656a94a5e1672f5.JPG

 

 There is another type of gusset plate made up on the opposite side. This will be used for connection between the two sets of truss frames. The bridge will be a double track (4 truss frames) unlike the Findhorn

Corner upper gussets also added but still trying to work out what is at the end of the truss frames (no really good photos)

 

 

DSC06154.JPG.daf8b44ac70ebc8b165efb0a4686a71c.JPG

 

Possibly channel section back to back?

 

 

Still waiting for the rivets from Archers (they have been bouncing around the States for the last 9 days). So moved on to the deck for a change.

Back in the early days of this build the bridge deck was widened. The cross bearers were widened so that walkways could be accommodated each side of the double track. This would need the intermediate braces to be widened also, as below. Made up of 2 braces (cut an butted together, leaving the position for the steel stiffening strips to be unchanged).

 

 

DSC06162.JPG.360346149f505df0c97c07fd26428b18.JPG

 

Now fitted to the deck, the steel strips threaded and glued up after setting square

 

 

DSC06164.JPG.5f33e63c8df7087e0078fd929f1f772c.JPG

 

 

DSC06165.JPG.ccfa9eb2332943a180518394ceb737ed.JPG

 

Also need to work out the cross bracing diagonals as shown in the centre of the photo below. Possibly angle back to back and connected to the lateral cross bracing.

Rather slender pieces which would not add a great deal of strength but perhaps needed as a construction aid?

 

 

image.png.d8051e783ed161e5dec3e0e91576b9c2.png

 

I should have had a trip there to get up close during the refurbishment project!

 

 

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The resin rivets have arrived from Archers. Quite a lengthy process. There are 320 decal rivet strips to apply and I've completed 75% of them. Hopefully this will have been worthwhile as they are quite prominent on the Findhorn diagonal beams.

 

 

1467133265_Rivetsondiagonals1.png.f1f552cf3ccd4ae4804a558134b12fe6.png

 

 

1196077582_Rivetsondiagonals2.png.688ea22f7c72821f4f0f07d9fecb098d.png

 

Here are the rivets used. N scale gave the right size and spacing. Fortunately, for the double row of rivets I was able to cut out the two rows in one decal strip.

 

 

DSC06206.JPG.1dab03b927ae1b7aa4fce5885b2c8501.JPG

 

I ended up with a slight variation on the method as shown in the Archer turorial video. Instead of making a cut in the clear film , I found it easier this way:

a) cut the decal to the required length

b) shift the decal off the backing at one end (light finger touch needed), and hold the exposed backing paper with tweezers

c) move the decal from the backing at the other end

d) lay the part-removed decal onto the 'wetted' workpiece and hold with a blunt cocktail stick

e) slowly pull the backing away with the tweezers

 

Here is the Archer video https://www.youtube.com/watch?v=aptnvFeEqio

With the 'Archer' method, I found that the backing tore easily at the place where the film was cut through. For the small decals with rivets, the clear film is simply slid off the backing with a cocktail stick after placing it on the surface of the model.

 

Needless to say, I hope the painting does not hide the rivets too much. I may well need to highlight them during the weathering.

 

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Time to have a go at the ends of the truss frames as seen on the Findhorn

 

 

1152212984_Trussframeends1.png.1f41141c7b442711f56ad844731c840a.png

 

1219634385_Trussframeends2.png.8809a3f2e6947c22ad237cc200b0f220.png

 

There appears to be beams top and bottom (better seen on the Forth bridge arrangement), and then channel sections back to back.

I will be using parts from the CVMW single truss bridge sprues as below

 

 

DSC06150.JPG.209ae357c56718db270dc11bfabf55e7.JPG

 

8 of these needed (4 ends top and bottom). The exact width was measured between the plate stringers on the deck assembly; minus the truss frame beam width where they are attached. The above parts are then cut and butted together.

Again the sander makes a good job of this

 

 

DSC06152.JPG.cd6cabec32475ffc657704208fd65d56.JPG

 

To get the accurate width these were sanded and measured with vernier callipers

 

 

DSC06159.JPG.27d4839a7f1358b40892d85b9c8b5401.JPG

 

From this point the unwanted material could be removed and the channel section added. As these pieces are cut to a length and angle which was unknown a jig was set up. The temporary white square tube sections are to the height of the end assembly which sits between the end gusset plates

 

 

DSC06211.JPG.14f74dd7ad7a277200a734d39f26aaa1.JPG

 

Another useful bit of kit (sitting on the shelf ready to use sometime), can be seen. A metal tray with square magnets. No matter how accurately parts are made so far, there needs to be some allowance made for tolerances so the 2 of the channel section joins will be finally made on assembly to the truss frames.

 

 

DSC06213.JPG.2a021dea06fcf0d3ff5dcf6c855c9af5.JPG

 

The next stage is taking some working out, as most of the painting and weathering of the truss frames needs to be done before assembly. Access would be impossible later.

Gluing after painting is an issue, so either masking off or scraping back paint at those positions will be needed.

 

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Painting of the truss frames started. The styrene colour mix of black and white needs to be addressed first

Step 1

So a black primer coat was first air brushed over the white diagonals (to provide a key). Only 2 of the 320 decals came off in the wind. Not too bad I guess.

 

Step 2

This was followed by brush painting of the same primer over the white parts including all the white H sections sitting inside the outer beams.

 

 

DSC06219.JPG.dab4942f6e7cb9e01c6e7590dfd4c30e.JPG

 

 

DSC06221.JPG.104250601c9edd35942c8b2856a22cb4.JPG

 

This is just the primer and I need to ensure the paint layers are particularly thin over the Archer rivets (OK so far)

 

 

DSC06222.JPG.17ba2f6a47088abe7f380d079b4570ef.JPG

 

Next is a primer coat over the black styrene

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Painting continued

Step 3

Next are two thin air brushed coats of primer over the black styrene.

Panzer grey acrylic surface primer used

 

 

DSC06225.JPG.c8def1b50f37d157cac3814ceaee3aa2.JPG

 

 

DSC06223.JPG.01f5a6ace1b517b38cbb2ac2904a9714.JPG

Now I need to replicate as best as possible the steelwork before the Findhorn viaduct was refurbished, but perhaps not particularly neglected.

Fortunately I managed to find a couple of pictures of the steelwork before painting

 

 

1619550977_Weatheringinfo1.jpg.b89fb8c28679bf47ca7194402477b2b5.jpg

 

1796194773_Weatheringinfo2.jpg.4d2073aece4c28ac2a85bf64f3e530d2.jpg

 

Only small areas of rust on ledges, some discolouration and flaking of the paint. The dirty appearance and some green patches can be added during weathering. The colour fading might be done with washes. The initial colour variation and modulation will be done by varying the base colours.

Step 4

Initially a light base coat has been air brushed with the following mix:

8 drops thinner : 12 drops battleship grey : 2 1/2 brush loads of flint grey

 

 

DSC06230.JPG.1420be419cab30cf86feb9abdaeb5778.JPG

 

DSC06228.JPG.f698fa68e88b2f57548a258b04aa3a92.JPG

 

 

 

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Next is my first go at colour modulation. This attempts to accentuate shadow and highlights.

Step 5

Applied to the underside of the diagonals. A very light air brush of panzer grey (12 drops thinner to 8 drops of paint), and on the top side of the diagonals a lighter shade with just the slightest hint of green from lichen (12 drops thinner + 12 drops battleship grey + 2 brush loads of flint grey + 1 drop of Vallejo grren gry 70.886).

This is a thinner mixture as the pressure at the air brush was turned down to allow a close proximity when spraying.

 

Step 6

Weathering. A thin wash of enamel track wash applied  to all of the surfaces. This was heavily diluted with white spirit so was more of a 'filter' than a wash.

 

 

DSC06236.JPG.7dbc107ddb13e049cba8bb32fe54f9d2.JPG

This is the result so far:

 

 

DSC06237.JPG.4e839683093e28b24dd6ea0ae6122ec8.JPG

 

DSC06238.JPG.b2cafe04bf060b78e02bca2820ff43bc.JPG

 

All four truss frames reached this point.

 

Step 7

To show patches of colour fading emamel neutral wash was was used. Thinned in a pallete and applied with a small brush and blended in with a small flat brush.

 

Step 8

Pigments. Army Green for lichen, Burnt Umber for rust, Urban Industry Dirt for 'Dirt' accumulation.

Needless to say the green on diagonals is hardly on the brush and very little when applying the other two. I use the technique taught me by Mick Bonwick. Shake the conatiner, open up and only use the very fine pigment which is attracted to the inside of the lid.

 

 

DSC06240.JPG.7b823f9a93fd8eaba2f2bcb2b5a848e0.JPG

That's one of the 4 truss frames painted and weathered as far as possible. Will be finished off after the cross beams are installed.

 

 

DSC06242.JPG.8db86cddc20fd46f42a3742fb16990fd.JPG

 

DSC06243.JPG.eb3ba97af479aea18a7a25d929c6420b.JPG

 

DSC06244.JPG.2f01093933669138c7c7af053575f335.JPG

Pleased that the Archer rivet decals are still visible on the diagonals :)

 

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The 4 truss frames are now weathered with washes, and pigments are completed except for the outside surfaces of the beams. I still need to handle the frames during assembly

 

The end frame assemblies plus lattice cross beams have also been painted and partly weathered

 

 

DSC06245.JPG.c67072ac948e4c83e55760dd137a3167.JPG

The sub-assemblies have been used to connect the two pairs of truss frames as below, and some cross lattice beams also added

Superglue was used for this - three different grades (drying times) depending on the joint

 

 

DSC06247.JPG.71561338fc95c37061956a1eee233658.JPG

Note that these are up-side-down and further weathering will be done on the underside and the ends

 

 

DSC06248.JPG.15e1fc0471ec91def090e6da102b59f1.JPG

 

 

DSC06250.JPG.1c506126e7afa7487de0de2db24c3523.JPG

Now that the frames are connected, the required length of the remaining lattice cross diagonals could be measured (= 92mm). This will need 2 lattice sections cutting out of the cross bracing which is included in one of the CVMW single Pratt truss bridge kit sprues (12 of each type needed)

 

 

DSC06156.JPG.e449a08cc6e931ea10375653da311739.JPG

Needs to end up as this design

 

image.png.b843bc70403f8b6d58535477becfaac0.png

So the truss frames are not far away, then back to the deck assembly

 

Edited by zr2498
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Well, it's taken a few hours to get all of the photos and images reloaded to this thread. Just one missing from LNERGE posted 7th Feb.

I hope it has been worthwhile. I did not see any point in adding more on the build progress unless the project from start to current date was fully available.

Hope to add more on progress later today.

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The cross beams which connect the two truss frame pairs have been cut from a part in the CVMW double track Parker bridge kit. Only 4 of these will be required.

 

DSC06252.JPG.957f8b1c3ba808bdb354d9767c3851a1.JPG

 

These, together with the diagonal lattice cross beams have been primed, base coat painted and a track wash applied. Further weathering will be done after installation to the truss frames

 

DSC06274.JPG.ce0b10245a7ce572f84ae66d544c7a71.JPG

 

Some progress has been made on the deck, however the truss frames and the deck cannot be connected until the maintenance walkways have been fitted into the frames.

The plan is to have 2 walkways with a platform connecting the two and a ladder access from the deck which will sit between the two pairs of frames. As this is double track the arrangement will differ from the Findhorn viaduct but the basic design of the walkway will be as close as possible.

Here are some pictures of the Findhorn

 

789532291_Walkway1.png.6f61deb93a682570d03b249d640cf734.png

 

This one shows an extra platform to access the central walkway and a ladder from the outer edge of the deck

 

362220583_Walkway2.png.e5213d93d843fef4168b4b37de7562c4.png

 

This one shows the underneath of the walkway

 

1065814969_Walkway3.png.51549d2e114191a32e3de782ca3c6a41.png

 

I hunted high and low for a suitable RTR walkway, or even something to kit bash, but realised I needed to scratch build this one. The walkway will be visible from above and below where it will be sited on the layout, so there needs to be representation of the wooden decking from both view points

 

Time consuming, but I have opted to use stripwood for the wooden deck. Only 400 pieces! This was sourced from a hobby shop that supplies materials for model boat building. Again the 'chopper' ensures consistent cut lengths

 

DSC06258.JPG.614ab9268310f3a220a62d36715c1806.JPG

 

I made a mock up of the design to see if it would look OK. Holes will be drilled into the stanchions for 0.5mm brass wire.

 

DSC06267.JPG.ed7ce123f3e3332fedc4b696045f61d6.JPG

 

Materials used

 

DSC06269.JPG.89e48d1b431623e02a3ac3f14b7bea39.JPG

 

 

I would prefer to paint all of the 'steelwork' before installing the wooden deck as the painting and weathering of the wood will be quite different.

So a method was needed to construct the steelwork without the deck in place and all of the parts to be accurate.

A pair of jigs were made, to set the distance between the longitudinal angles and to space the distance between the cross angles (underneath the deck).

 

These are the jigs

 

DSC06270.JPG.7c3fe093fa7d5977d75ac3a066563bd6.JPG

 

And this is the construction method

 

DSC06272.JPG.bbd8c8584ccb4ec1d67b40bc35256103.JPG

 

Still need to work out how to construct the adjoining platform and ladder access

 

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Diagonal cross bracing installed. Photos show the underside of truss frame assemblies

 

 

DSC06279.JPG.52432755b78095bd733f551270294abd.JPG

 

 

DSC06280.JPG.04ff5361742e4d5bfa0914b7f0bc7196.JPG

Maintenance walkways started. The steelwork of the decks is complete and one of the four sides with handrails added. There will be gap in one side of each walkway for the connecting platform with ladder access

 

DSC06277.JPG.0976cf3c0905d85610cb6f29c537f4f3.JPG

 

 

DSC06278.JPG.0db6edc397fd557c07b97c517fece5e6.JPG

Some work on the deck:

A 1mm ABS sheet has been cut to cover the deck. This will represent a plated deck. The longitudinal edges of the deck will have the supports for the lattice handrails and triangular shaped stanchions

This photo gives an idea of the prototype

 

 

image.png.7f7ef5b297f3e1706e5e0f2399a125a4.png

There appears to be a flange and a rivetted support beam for the handrail. Edge pieces have been made up which will butt up to the ABS sheet

Made from CVMW beam sections

 

 

DSC06254.JPG.d4ccd8b10e7ff4b56f601175d91d9ca9.JPG

Extra styrene added to represent the flange

 

 

DSC06255.JPG.a1620d536e17822dc2f7af5f08ba3aa5.JPG

Temporary position as below

 

DSC06281.JPG.6ca8791c8f419c39994ec087d327f710.JPG

 

 

I have added 30mm extra length to the ABS at each end of the deck. The bridge will be removeable, and I was thinking of using magnets on the underside of the extensions to fix the position. I will need to do some tests to see if the alignment of track will be good enough

 

 

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On 01/04/2022 at 11:43, zr2498 said:

Well, it's taken a few hours to get all of the photos and images reloaded to this thread. Just one missing from LNERGE posted 7th Feb.

I hope it has been worthwhile. I did not see any point in adding more on the build progress unless the project from start to current date was fully available.

Hope to add more on progress later today.

Well, just hoping that the images I have reloaded do reappear at some time? Yes all back 🙂

Fortunately this time I copied the pages to a word file

 

Edited by zr2498
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2 minutes ago, Enterprisingwestern said:

 

image.png.e1b9a4d318c39369b07adf272c9a5a9b.png

 

There is P4 track going across this masterpiece, of course?

Got to keep up ones standards dontchaknow.

 

Mike.

Mike

I could, but then trains might derail! At least the plan is to use baulk timbers and include guard rails with chairs I purchased quite some time ago from Scalefour Society.

The bridge will be at quite an elevated level for the viewer, so perhaps not such a problem.

Sorry to let the side down.

 

Seem to be getting near the end point of this bridge construction now, but the design and production of the photetches for the lattice handrails will extend the timescale.

Have received the stone work castings from Townstreet which will be used for the bridge abuttments and arches either side. Another fair sized project.

 

Dave

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Painting started on the walkways

Initially, an enamel primer has been brush painted on the brass rails

 

DSC06312.JPG.c00ee2a33a9ad292e865d93e0d5c2df7.JPG

 

Acrylics will be subsequently air brushed now that the brass has been primed

 

Some progress  has also been made on the deck

This includes the rail bearers and outer deck plate supports

Materials used:

 

DSC06325.JPG.5bd46e29093c6223b2f6b307d9dae69a.JPG

 

The rail bearers can just be seen on the Findhorn viaduct as below

 

image.png.cbc0808b562d84feb1286237ec218708.png

 

The rail bearers were cut to equal length with the 'chopper', notches taken out where it sits under the cross bearer flanges and slots filed out where they slide over the intermediate cross supports

 

DSC06314.JPG.f3b012eae66cad987fdd9490a4bffff0.JPG

 

DSC06317.JPG.ec5dc2ed152f1e899cf5845f9b5e27d4.JPG

 

DSC06318.JPG.5e913a3f3b50fb9b6770e8f2e880afce.JPG

 

DSC06320.JPG.2e6e3627726f3aa08d0172e5762f3ee3.JPG

 

The rail bearers are positioned directly under the rails, although there will of course be a section of deck plate and the baulk timbers yet to add.

My neighbour very kindly loaned me the heavy glass plate which can be seen in the photo below.

This has been used to ensure the deck is flat and the rail bearers were pushed to the glass when attached so that the top surface was flush with the cross bearers

 

DSC06321.JPG.3cd5ceb745ffc980023a5318f202f618.JPG

 

DSC06323.JPG.4e0bae9d819626720c227dd5e4f77a6d.JPG

 

The outer deck plate supports have a notch cut out to fit under the rail bearer flanges and spaced as on the Findhorn

 

image.png.1ee4a221625072ad689f36a1f5222340.png

 

DSC06324.JPG.cec1aa26a5b4cf5f2b5cd3a0a089c454.JPG

 

The deck assembly is now ready for painting. At this stage, access will be easier prior to the deck plate being attached

 

 

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1 hour ago, Enterprisingwestern said:

 

It's now gone beyond praise!

Just as a matter of interest, have you kept a log of the number of hours you've spent on this masterpiece? Costed out at a reasonable £20/hr plus (not inconsiderable) materials etc, I'd love to know the cost!

 

Mike.

 

Good Morning Mike

When I started this project, I had an idea that it would not be easy, and would take quite some time. It has taken considerably longer than the M & GNR bridge I built for Little Bytham (Tony Wright), and that took long enough. That was a brass construction with some photoetch design, so very different.

BUT, this one has been as much about learning new skills and knowledge of bridge design as the build itself. I guess if I had known how long it would take, then perhaps I would have looked for an alternative means to a similar end. However no regrets, and seeing the results of the bridge as it nears completion is reward in itself.

I have not logged the hours, but I am keeping count of the number of components. 1,848 parts plus 320 decals so far.

The cost of materials will not be insignificant, and perhaps one day I will make an estimate. Fortunately I had lots of spare sprues from a kit bash done on the relatively simpler Parker Truss bridge built some years ago.

 

Dave

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The remaining deck plate supports have been installed

 

DSC06334.JPG.4ef64d359d3ab73cf18e855c43761792.JPG

 

First. the surfaces that would be glued to the deck were masked off

 

DSC06336.JPG.5313251562cdcfaac3b60c068fe3f05d.JPG

 

Then the white styrene was primed by brush painting with Vallejo black acrylic surface primer to get closer to the black styrene prior to further priming

 

DSC06339.JPG.1b4ef7a8ecb61197f5be2542dab9d61e.JPG

 

This was followed by air brush priming all of the deck surfaces using Vallejo Panzer grey acrylic primer. The walkways were also primed.

 

DSC06341.JPG.9763c7b083e48a7b16f707dbf3509025.JPG

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