Lattice Girder Deck Truss Bridge - Kit bashing

[zr2498]

Now it was time to add the deck plate. This is 1mm thickness styrene. The required suppport / stiffness is provided by the rail bearers and deck plate supports just as on the prototype.

It was attached using Butanone and needed to be done next to an open window as pretty toxic stuff!

 

 

Here is the deck plate and as explained earlier there are extensions each end to aid fixing of position on the layout via magnets.

 

 

The edges to the deck plate (which will support the lattice fence), were prepared earlier and could now be fitted

 

 

Splice plates were made to join the length of edge plates. These were cut from sprueson the CVMW double track Truss Bridge kit. Rivets have been removed where future fence stanchions will be attached

 

 

 

At the outer deck plate supports there is a connection to the deck plate edge plates as shown below

 

 

These were made up from more splicing plates on the CVMW sprues, and a styrene packer added where it steps onto the edge plate

 

 

And here they are installed

 

 

Now a chance to get back to some painting

The maintenance walkways which had already been primed, had 2 base coats of the acrylic mix airbrushed, and the first stage of weathering with enamel track wash was completed

 

 

 

The deck was primed and the same base coats applied

 

 

 

Weathering with pigments was completed on the underside of the of the truss frame beams and cross diagonals

 

 

And now some fun. Adding all of the wooden planking to the maintenance walkways. Glued on with PVA. These will most likely have a wood stain applied prior to weathering

 

 

 

Light at the end of the tunnel, albeit a very long tunnel!

[zr2498]

Next is painting and weathering of the walkways.

I decided to use the Lifecolour set of acrylic wood effects on the wooden decking. This was done by first, painting all the wood with a well water diluted mix of the base colours.

Note the trick to put aluminium foil over the pallette to save cleaning it each time

 

 

 Then using base colours and the shades to pick out individual wooden planks

 

 

 

This was followed by an enamel track wash covering (well diluted with white sprit), followed by dry brushing with wood cold light shade (very sparingly), a few areas of slimy grime dark where water might accumulate, a few areas of black smoke pigment and finally blend and tone down with urban industry dirt pigment

 

 

 

Now to finish off the steelwork with a selection of pigments

 

 

The photos of the Findhorn viaduct walkways are effected by refections so the colour are difficult to make out, but this is the original which is a fairly close match (I hope). I have assumed that the handrails were painted steel in the earlier period I am modelling, rather than what looks to be aluminium tubing.

 

 

Walkways are ready to install to the truss frames. Just need to prepare the ladder and brackets to the central platform

[Moonter]

1 hour ago, zr2498 said:

Next is painting and weathering of the walkways.

I decided to use the Lifecolour set of acrylic wood effects on the wooden decking. This was done by first, painting all the wood with a well water diluted mix of the base colours.

Note the trick to put aluminium foil over the pallette to save cleaning it each time

 

 

 

Ignoring for a second the amazing modelling on the bridge, that foil trick is genius!

 

[zr2498]

The maintenance walkways have been fixed into position, relative to a temporary positioning of the platform which is the reference

 

 

 

Now that the walkways are in place, the platform can have the added detail as it overhanges the walkways slightly. The ladder access will have base plates added before installation on the platform

 

This is the preparation

 

 

And details added. Painting and weathering to do on these.

 

 

Another bit of detail to add, are the diagonal 'construction' cross bracings as can be seen below

 

 

This needs to give head clearance, albeit not a very easy access in reality

 

This was drawn up on CAD and a template produced

 

 

For the construction of the sub-assemblies, the template was set up with fences

Stage 1

 

 

Enabling first fix

 

 

Stage 2

 

 

Second fix

 

 

And trimming / sanding of parts

 

 

The other detail are drain pipes which run from the deck surface to the bottom of the truss frames. Materials ordered

Painting of the extra details and weathering of the deck started this evening.

 

 

[john new]

Wow, phenomenal work. 

[zr2498]

Platform installed

 

 

Construction diagonal bracing installed

 

 

 

Now that the platform is installed, the accurate distance between the two truss frame assemblies could be measured and a representation of end flanges to the cross beams added to make up the distance

 

 

 

These will be finish painted and weathered before installation. The weathering of the underside of the deck has started. Even though it will be difficult to see, perhaps no reason to start compromising at this stage.

Not far away from attaching the deck to the truss frames!

 

 

Edited April 30, 2022 by zr2498

[Enterprisingwestern]

 

W O W.

 

Mike.

[zr2498]

The truss frames were joined via the short cross beams, so now time to weather the deck

 

Before proceeding the deck was sprayed with Testors Dullcote to seal the primer and basecoats already applied.

 

 

Then, applications of neutral wash (well diluted to be a filter), over areas to represent fading paintwork.

Next track wash, especially at joints and a little slimey green wash (well diluted), in areas that would be in the shade. For example at the ends where the abutments will surround them.

The track wash was applied by the rigger brush, first into the white spirit, then the track wash so that that it flows into the joints on contact. The thicker brush is used to thin and adjust the application before it dries.

 

The pictures below show the result of the the washes

 

 

 

 

Unfortunately, the photographs of the Findhorn Viaduct do not show any close up details of the underside of the deck.

I looked at bridges with a similar deck plate construction. Not many, as it is more usual for photographers to take pictures of the more 'glamorous' aspects (not the underside).

 

The Forth bridge shows some detail

 

 

And another is this one near Oldham

 

 

To get the effect of some corrosion just starting on the deck plates, I used the stiff brush flicking technique

Before proceeding the deck was sprayed again with a light Dullcote application

 

Old rust acrylic was used for the rust spots

 

 

Giving this effect, somewhat less than that above. It will need blending in

 

 

Final steps are pigments

 

 

Final result

 

 

 

 

Next will be the rather nervous attchment of truss frames to the deck!

 

 

[zr2498]

Today was the marriage of truss frames and deck. This was reheared a few times before glue was applied as it it could not be adjusted afterwards

 

Done ....... And apologies for the number of photos, but I reckon this is a 'put the flags out' event

 

 

 

 

 

 

 

 

 

 

Drainage pipes, the lattice fencing and of course, the trackwork remaining

 

 

 

Edited May 2, 2022 by zr2498

[zr2498]

A little more progress:

 

Painted and weathered the ledges between deck and truss frames, which I did not notice until checking a photo. These surfaces were kept untouched until the deck was glued on.

 

 

Now some CAD and photo etch design. Have not done any for a couple of years, so initially slow going. The design will be a slight variation on the Findhorn deck fences, but will give the same overall impression

 

 

CAD design so far

 

 

Having to think in 3D is a brain teaser. Converting these drawings (when finished), to the photo etch files will also be challenging.

 

I've ordered some pipe brackets from ModelU for the deck drain pipes, and the track / deck might be based on this

 

[mike knowles]

Stunning work.

[zr2498]

The photoetch design for deck fencing is complete. Quite a task but now it needs to be checked with each colour in turn, and then layers and dwg files prepared for the etchers.

 

I was quite surprised how many components in the fencing (124!)

 

Amongst the design below are Patriot smoke deflectors for a friend who models in N gauge.

 

 

I've now got the components for the drain lines. A few experiments were done to get a reasonable bend in the 1.3mm styrene.

Hold the bend near a flame (but not into it), then plunge to cold water.

 

 

 

 

[john new]

Stunning work.

 

[zr2498]

To fit the drain pipes to the truss frame beams, there needed to be an extra plate added to to back of the pipe brackets. This would allow the pipe to clear flanges and splice plates.

0.5mm thickness strip added as below

 

 

Positioning of the brackets and the required bend was marked on the 1.3mm diameter rod

 

 

The brackets were glued in place (remembering LH and RH), using a glass plate to ensure all of the 'flats' of the brackets would mate with the truss beams

 

 

Painting as before with acrylic primer and then a base coat

 

 

Fitted and weathered with track wash and then pigments

 

 

AT LONG LAST! Some trackwork

This bridge will be fitted with a track layout typical of that found on bridges, which includes longitudinal way beams and check rails.

 

So, that's double track with check rails = 8 rails

Preparation:

 

 

The L1 bridge chairs are narrow, but as the prototype was a single casting holding both rails the L1 chairs needed to be trimmed on the insides after fitting to the rails. They will be be pushed together when fitting to the sleepers to represent the single casting.

A 1mm shim (check gauge) will be used for the spacing.

After threading and trimming 648 chairs:

 

 

The photoetch for the deck fencing is on order (about 4 - 6 weeks delivery).

 

Wood strips 7mm X 3mm have been ordered for the way beams, and a smaller size for the cross timbering transoms).

I still need to work out how the steel transom bolts, which pull the way beams together against the spacing cross timbers, will be best represented.

 

 

Edited June 7, 2022 by zr2498
Corrected terminology

[zr2498]

The detail of track timbering will be a compilation of information from different sources.

Here are a few pictures of baulk timbers, transoms and transom bolts

 

 

 

 

 

The baulk timbers are made up from the 7 X 3.2 mm strip wood 44mm and 48mm length, and the transoms from 3 X 3mm, 8.5mm length to give the required track gauge with check rails included

 

 

The transoms were sanded to give an accurate width and checked with the vernier

Then into the paint booth for wood staining

 

 

A couple of days drying time needed.

[zr2498]

Need to get back to the bridge.

 

Perhaps the early delivery of the photoetch for the lattice fencing, (above deck) will do the trick.

Beautifully etched by PPD Ltd.

Just have to hope that the design is correct and it will go together as intended.

Long, delicate pieces to handle until the sandwiching of layers makes the fence sections more robust.

 

 

[zr2498]

Where did the time go?

It's been June since the last post, so time to get back to the bridge.

Fencing - above deck

 

Parts removed from fret and cleaned up

 

 

 

Starting with the fencing stanchions

Flanges of the outer faces folded

 

 

The stanchions consist of 4 layers. Two flat plates making up the centre to give the required thickness, and the two outer folded faces.

The sub-assemblies were constructed by tinning faces with the conventional soldering iron, and then joining via the resistance soldering kit.

 

There are protruding pins on the inner plates which will fit into alignment holes in the lattice fencing. These needed to be well aligned, so jigs were set on the base plates via steel blocks and magnets.

The sequence is shown below:

 

Tin one centre plate - 179 solder

 

 

Join the two centre plates

 

 

Clean up edges (needed for correct alignment

 

 

Tin one side of double plate - 145 solder

 

 

Add one facing flanged plate

 

 

Tin the remaining outer flanged plate

 

 

Attach to the assembly

 

 

The outer face of the stanchion has an additional facing plate. A bend was put in via a scriber, then it was tinned

 

 

Attached to the assembly

 

 

Lots of cleaning up (14 stanchions complete)

 

 

These are a close approximation to those on the Findhorn viaduct

 

 

Next will be the fence top flanges. Yes, I am puitting of the difficult assembly of the lattice work!

 

 

 

 

 

 

[zr2498]

Fence top flange plates

 

Strips approx 530mm length are used for the total length of flange plates across the top of each of the two fences

There is a lower plate with slots which locate tabs on the top of the lattice panels. The upper plate has splice plates added.

 

Here is a typical section of the construction drawing

 

 

 

The lower plate is tinned using 170 solder

 

 

The top plate is attached via the resistance soldering kit. Pegs and magnets are use to align and set the two parts

 

 

Splicing plates are tinned using 145 solder

 

 

Splicing plates attached and cleaned up

 

 

 

 

Edited September 4, 2022 by zr2498
Spelling correction

[zr2498]

Now for the lattice build of the fences

 

It consists of 4 layers. The 2 internal layers being the lattice complete with rivets, and the outer 2 forming the frame for the 'sandwich'

 

First the 4 layers were tinned (179 deg solder)

 

 

The design included 3 off 1mm diameter alignments holes to pass brass wire through. The 7 holes for the stanchion pins at 0.3mm diameter could also be used for aligment by brass wire as shown below

 

 

 

The 'sandwich' was tacked via the resistance soldering kit. As the layers are only 0.15mm thickness the votlage was set at 2V rather than the 3V usually adopted.

 

 

Lots of flux between each of the layers and one section at a time. This method enabled the 4 layers to be joined in 'one shot'

 

 

 

Addition of clamping plates (opposite the stanchions)

 

Tinned with 145 deg solder and RSU used again

 

 

Lattice sub-assemblies cleaned up and ready for assembly of the stanchions and top flange plates

 

 

 

Lots of rivets and no punching 🙂

 

[DGO]

It has to be said, this is a really impressive bit of work

[zr2498]

Next, the top flange plates were soldered on (conventional soldering using 140 deg)

 

 

Both fences with top flange plates and cleaned up

 

 

 

It was not possible to solder the stanchions to the fence sections. Perhaps the next design would enable this!

However, the sub-assemblies could be attached via 2 part epoxy. The alignment holes / pins were a great help

 

 

The completed fence sections

 

 

Just had to see how they would look on the bridge albeit they still need to go to the paint shop

 

 

The sections are a snug fit over the lip on the top of the deck plate. So much so, that they will not require any adhesive and could be removed in the future if required

 

 

 

A couple of coaches put on temporary track to give an idea of the scale

 

 

Painting and weathering of the fences next, then finish off the trackwork

[Vecchio]

An absolute masterpiece. Congratulations. 

[zr2498]

Shortly after fixing the stanchions to the lattice fencing frames, every other overlap of the lattice pieces was superglued. I did not want these to separate after painting showing bare metal underneath.

 

 

It's been a while since I have made progress on the bridge. I guess the trackwork was always going to be 'a challenge'.

Anyway here goes. As previously mentioned the trackwork over the bridge will include longitudinal 'way' timbers, and have guard / check rails included.

 

To make assembly of the trackwork 'off bridge', and to perhaps have that sub-assembly detachable a second styrene bed was made up to fit between upstands supporting the fences.

 

 

 

The timber lengths and the cross timber transoms had already been cut to length and stained.

 

To position the transom bolts (inside), and the nut/ washer / screw combo (outside) of the baulks the Proxxon bench drill was used with fences set up as a jig for both X and Y axis to make 0.7mm diameter holes.

 

 

The transom bolts were cut from 0.6mm diam brass wire at 14.5mm length and a piece of 1mm long wire insulation used to represent the clamping of the two halves of the transom bolt assembly

 

 

12 track bases per rail X double track X 2 per assembly = 48 bolts

 

 

Assembly of the track bases.

Again, jigs used with 8.5mm slip gauge blocks set between the timber baulks

 

Step 1

 

 

Step 2

 

 

Step 3

 

 

24 track bases

 

 

Next will be to position these on the styrene bed, with a 0.5mm uplift to match the 'proposed' walkway timbering.

Edited December 2, 2022 by zr2498
Correction to terminology

[zr2498]

A start to the bridge track (Code 75 bullhead rail) laying at last!

 

The track bases (timbers), were aligned and fixed together by gluing (with Butanone) to a pair of styrene strips This will give the 0.5mm uplift to match walkway timbering depth.

 

 

2 track lengths

 

 

First for the running rails. 7 L1 bridge chairs (trimmed) per way beam. Fixed via track gauges and Butanone. This was done adjacent to an open window to aid ventilation.

 

 

Running rails complete and checked with test wheelset.

 

 

 

Next will be the guard (check) rails

 

[Vecchio]

Inspired by your work I just ordered myself a bridge kit from Central Valley Model Works. Postage is quite a bit, but I think it's worth it.