Sunday, 25 November 2018

Scooter's Bridge

A few months ago, I was contacted by “Scooter”.  Scooter informed me that he once lived in the Wagga area, and had constructed a HO scale model of a small bridge on the line just east of the Wagga RAAF base.  Scooter has now moved to Western Australia, and no longer modelling NSW HO.  He offered me his model, as he thought  it would be better on my layout, than languishing in a drawer.



Worse for wear, the rail bridge is visible from the Sturt Highway just east of Forest Hill
This small bridge is located in a field, and visible from the Sturt Highway.   I searched my slides taken in the 1980s, and 90s, and disappointingly, I could not find any of the bridge.  Fortunately, the bridge still exists.
So armed with a high zoom camera, I traveled along the Sturt Highway.  The bridge is located on private land, and trespassing to get closer would not be appreciated by the farmer.


The camera was at x 36  zoom, and I used a fence post to stabilise the picture, but there are some optical distortions that make the bridge look even worse than it currently is. . The wing abutments had eroded in the 30 years since the last train.

View from O'Hehirs Road.  Note the 2 piers - one is 3 posts, the other is 5. As the height of each pier is the same, I really don't know why there is a difference
Another picture from O'Hehirs Road.  The telephoto effect makes the 42' of bridge look like a small culvert. What is obvious is that the line dips down to the bridge, and there are no checkrails

The bridge has 2 piers, and three 14’ openings.  What I did find unusual, was that the two piers have a different construction – one having 3 piles, and the other 5.   I don’t see any photographic evidence of bolt holes on the angled bracing to indicate that the missing 2 piles were ever there.  The abutments have heavily eroded.    My picture taken from O’Hehirs road also show no checkrails

Scooters bridge model arrived in the mail, and I was extremely pleased.  The detail work is brilliant, and it is great to see an alternate approach to building a trestle bridge.   Scooter has modelled both piers with 5 piles,  and this just adds to the mystery.    I suspect that I will be locating Scooters Bridge on the layout’s lower level, just before the helix.  And the Scooter’s name will be retained – a lot better than “unnamed trestle bridge in a field”

Scooter's model is in far better condition than the prototype. Scooter has added all the sleeper bolts, which makes me think I need to add these to my kyeamba creek trestles



Scooter's models of the wingwalls show what the prototype bridge has lost

Parts loosely assembled.  Compare this shot with my prototype bridge picture taken side-on at the start of this blog post.


Thanks Scooter.  

Sunday, 11 November 2018

The un-named creek bridge




Kyeamba Creek Bridge – pt 4 - the unnamed creek

It was really great to get to the Wagga Wagga model train exhibition last weekend, seeing some great layouts,  and even better to renew or make new contacts.


Stockinbingal layout, built by the Wagga Wagga Railway Modellers, and recently restored by Rodney Smith and team, made a welcome reappearance at the November 2018 Wagga Wagga model rail exhibition.  This layout was featured in AMRM, and AJMR almost 2 decades ago.


  The Tumba Rail group had a stand, and their brilliant display of pictures on the Tumbarumba branch never fails to inspire.  Mark Pottie (Tumba Rail) advises that he is planning a new booklet with more pictures of the branch to Tumbarumba, including the stockyard siding at Ladysmith.   I also received valuable information, including a picture, and mudmap of the Humula sawmill.    During the weekend,  I had an unexpected visit to my home in Junee, by Peter Beyer (“Branching out NSWGR” blog). Peter gave me  one of his shapeways printed toilet block for Tumbarumba.  Fantastic detail.  The model will still need to be finished, but I have a few projects to do first – one of them is the Kyeamba Creek Bridge

All the piers are now attached.  Only the longer ones are touching the wooden base.  I have also added the tie plates to the bridge sleepers, in a similar fashion to my earlier effort on the Murrumbidgee River Bridge

Addition of painted rail, shows how the Peco code 100 track will connect.  The Peco sleeper base will need to be painted too, as it looks far too plastic.  Ballasting will also help.  But I am still unsure if I will use code 100 rail, or opt for a finer code 70.  If I choose the latter, I will handlay instead of using Peco.

The bridge, and the rail have not been secured - as it will be easier to detail the scenery under the bridge if the bridge isn't there


As I indicated at the end of the last Blog, I had a lot of repetition on the Kyeamba Creek bridge.  Well, I am happy to report that the bridge is now essentially complete – so it was time to move onto the unnamed creek crossing
I have shown this picture before.  The end abutment had been washed away in the 2016 rain event.  This 3 span bridge is around 100 metres away from the Kyeamba Creek bridge, and is good from my modelling viewpoint, as a model of its timber abutments will use the abutments I had in the Ironbark models kit

The third span of the bridge over the unnamed creek was added to the existing 2 spans previously constructed almost 30 years ago.  The extra span needed sleepers, but the original Ironbark Models provided only enough sleepers for 8 spans (6 spans worth of sleepers were used on the Kyeamba Creek bridge).  I had thought that I would raid my supply of NE stripwood for the remaining sleepers, To my dismay, I didn’t have the right size in stock.    Quick inexpensive solution – cut my own from a sheet of scrap basswood.   

The basswood sheet is sliced into sleeper width strips.  Make sure your knife is extremely sharp, and use multiple passes, and not much pressure. 

Once the strip had been cut to length, I compared my batch with the originals in the kit.  Yes, mine will need to be weathered, but from a dimensional viewpoint, spot on

The abutment construction starts with the attached support pier. 

The end abutment pier was previously constructed.  The timber for the wings was still in the Ironbark models kit, and this was cut to shape using the templates supplied in the kit

The poles were glued to the wing wall timber at the appropriate spacing

The wooden poles were cut to shape.  Note that the wing walls slope slightly inwards, which means shaping the bottom at a slight angle off the vertical
I made a base for the wall sections to attach to.  The 3 sub-assemblies were glued together.  Later I installed a reinforcing block of wood behind the end pier, and wing walls


Now that the abutment was built, I used the 3 spans to determine where the abutment needed to be installed on the board.  Note that the base of the abutment sits above the baseboard (and the creek level), so some extra tweaking of the benchwork support was done to maintain the correct height.  

New and old sleepers to go on the third span.  I am getting happier matching my original weathering.  I had not yet fitted the nut/bolt/washer castings to the wood beams in this picture 

I used the deck of the 3 spans to position the end abutment.  Both abutments are sitting on wood supports, above the wooden board.  The newly made abutment is not finished, but the effect is there.  The 2 intermediate piers are still to be built



Both bridges, but there is more work on the unnamed creek bridge, before it is ready for scenery.  Length of the board is 1.2 metres, and this should be enough diorama for any future branchline train photography


Once I complete the woodwork for the unnamed creek, I will start on the  scenic work.  Only then will I add the bridges,  rail, and ballasting.    This simple project is taking far longer than I would have originally hoped.

Until next time.    

Thursday, 18 October 2018

Kyeamba Creek Bridge - 3


Some things just cannot be rushed.  But, distractions aside, I am slowly moving forward  with the Kyeamba creek bridge build. 


In my opinion, the set of drawings done by Ironbark Models are the best ever done for an Australian kit, before, or since. These drawings are printed on glossy foolscap paper, and are remarkable, as the kit was limited to only 250 kits (my serial number is #11). Ironbark models disappeared from the scene shortly after their bridge extension kit hit the market.  I would be interested to know what happened to Ironbark, and how many of their kits were built, or still remain in cupboards, to be rediscovered.  


Building up the concrete “plinth” that supports the ends of the Kyeamba creek bridge timber spans was done with layers of 3mm MDF.  After sanding, this was glued to the abutments, and then painted with Floquil concrete.  A layer of 3mm basswood was then glued to the top of the subroadbed pine.   The wooden timbers were then glued to the top of the plinth, and the top of the abutment.
This subroadbed pine was cut to accommodate the existing timber abutment for the unnamed creek. 

The track embankment between the two bridges. I have already added a section of basswood to bring the height of the embankment up a bit - so the later cork layer will be at the correct (I hope) height
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After some adjustments,  the base was ready for the Kyeamba bridge deck.

As my recovered bridge deck was only 4 spans, an extra span at each end was added.  I did have some additional stained timber in the Ironbark models kit box, however, this would only give me one span.  For the extras, I used 12” square  North-eastern stripwood.  However, this led to another problem – matching the stain.  For the life of me, I cannot recall what stain I used almost 30 years ago.  The Ironbark kit instructions mentioned a combination of Floquil “driftwood” and “walnut”, not that I had those at the time, or now.  So I made up a concoction myself from thinned down floquil paints, but it didn’t really match.  As my bridge will be viewed from one side only, I used my older stained  timbers on the viewing side, and the newer mis-stained timber on the other side.
The two bridge decks, after adding the extra spans


Some trimming of the bridge timbers to fit the gap between abutments, and time to start on the detailing
Due to a glitch with my measuring, the Kyeamba creek bridge ended up around 5mm too long to fit between the abutments. I would like to blame the thickness of the MDF, but the reality is that I goofed.  Anyway, both end spans had to be shorted by around 2.5mm - which is about 8 scale inches.  Hopefully it won't affect the appearance too much.  As a sideline, the official railway survey of the line states that the end spans of the Kyeamba trestle bridge, are 14 feet, and not 24 - but my visit, and photos show that this is incorrect.

The kit supplied Grandt line 1” Nut Bolt Washer (NBW) castings. These castings were painted rust, and holes drilled in the bridge deck – top and bottom.  Whilst fiddly, it actually doesn’t take a huge amount of time.  Good lighting, steady hand, comfy chair, and good music to listen to is suggested. My method is to fit a 0.6mm drill bit into an Archimedes pin vice drill, and a few seconds later, the hole is made.   After making half a dozen holes, transfer some PVA glue on the point of an ordinary pin to the hole.  Hint. I use the point of the pin to make the hole entrance slightly larger, and this also leaves a ring of glue around the hole entrance.   I use tweezers to transfer the casting.  Push the casting home, and the glue dries. Repeat the process until all NBW are installed

Bottom of the span.  Note the rebates in the corbels for the piers

Top of the span, also showing the Grandt Line NBW castings. The original plastic colour is black.

Sleepers are glued into the spaces between the NBW castings

The sleeper spacing is every 5mm - so getting the NBW castings drilled into the timber at the right spacing is fairly important.  Even so, there is still a lot of variation in my done by hand drilling.


New timber piers were made.  Again, I did not have enough stained timber to make all the new piers, and it was not possible to disassemble the exiting piers, as they were already cut for the now incorrect cross bracing.  
I raided my supply of timber, and found some dowels (OK meat skewers) of almost the correct scale 12”  diameter .  These were distressed with the saw blade, and then stained using a different method, which worked really well,  far better than my original staining method.  I may have to re-stain my original bridge  timbers to match.

The deck was again fitted between the abutments, and measurements taken for the 2 main piers that will attach to the timber base.  Shaping and fitting the piers into the jig was the easy part – cutting out the slots for the cross bracing was not.  Fortunately, the Kyeamba bridge only has cross bracing on 2 piers.
The central timber piers are 61mm high.  I have started to cut the rebate into the pier for the top chord.  The angle brace rebate is still to be cut.  Once one side is done, remove the assembly, and rebate the other side.  This is not easy, and I understand why it is easier to simply glue wood together to get the shape.  The weathering of the dowel has exceeded my expectations, and looks old and weather beaten - after all, the piles were installed for almost 100 years when I photographed the bridge, and have survived floods, and insect attacks.  


After completion of the pier, which included fitting yet more NBW castings to each joint, the pier was installed onto the bridge deck, returned to the bridge abutment base, and checked.  All OK, the pier was glued. 
 
One pier down, 4 more to go.  The peco track on the embankment has been put on some cork to check the transition from plastic sleepers to wood.  My original idea was to use code 100 rail for the entire layout, but I may substitute code 70 on the bridge area, and hand-lay the small area of the embankment with wooden sleepers.

 
There is much repetition now for the next lot of piers.  Then I have the unnamed creek trestle to finish, followed by the landscaping.  I keep telling myself this is a hobby.


Stay sane, build a model.

Wednesday, 26 September 2018

Kyeamba Creek Bridge - 2


I really do not know where my time goes.   Progress on the bridge has been glacially slow on the modelling front,  partially because some indecision on my behalf on the best way to proceed,  although I have been able to continue with some rollingstock acquisitions, a brass loco repair, and more research. 

8 car RUB set hauled by 3825 leaves Wagga in 1962.  Photo taken and kindly provided by Tony McIlwain. The train is passing the upper quadrant signal, which we now believe was to protect the Edward Street level crossing.  No, this picture  has nothing to do with the Kyeamba Creek bridge, but this image and others, are some of the reasons why time ran short on the Kyeamba creek model   


Now that I had a dimensioned sketch, (see part 1) the first part was to locate a suitable piece of pine.  My desire was to include both bridges on a single section of timber plank. Whilst I did have some chipboard, and some 9mm thick ply, these materials were either too heavy, or too bendy.  Sure the ply could have been re-inforced, but a trip to Bunnings located a 1 metre or so long pine plank, with enough width to fit the bridge wing abutments.  The width is also in keeping with my future plans to minimize the width of the upper deck benchwork.

Solid pine was used for the subroadbed “causeway” between the two bridges.  This also assists with stiffening the pine plank.

The two bridge openings were marked on the plank, and the pine subroadbed was glued between the 2 bridges. 3mm MDF board (also obtained from Bunnings), was cut according to the sketch, shaped, and glued into position for the Kyeamba creek bridge.  Gaps were filled with Aldi brand filling compound 

The Kyeamba Creek bridge opening is around 50cm wide.  It didn't come out too well in the picture, but I have penciled in the location of the creek, and the timber piers.  The pine "causeway" subroadbed extends to the unnamed creek, and I have left enough space for this bridge too on the plank.  Distance between the two bridges is the compromise.  The concrete abutments are 3mm MDF.  This gives a thickness close to the 1 foot estimate of the prototype abutments.  Note too that most of the abutment will be buried in scenery


The unnamed creek will have traditional timber supports.    One thing that I assumed, was that the water level in the unnamed creek, and Kyeamba creek would be the same, as the railway is fairly level between these 2 creeks (confirmed by looking at the railway gradient diagram), however, the water level for the unnamed creek is higher than Kyeamba creek by at least a metre, which might look a bit odd on the model.  To get around this, the unnamed creek may be modelled as a dry stream
Next step was to attack the Ironbark trestle bridge that I recovered from an earlier layout.  The only thing wrong with the trestle, was that the timber piers were the wrong height, so needed to be removed.  The bridge deck though was perfect for reuse, so I didn’t want to damage it.

My original trestle bridge segments

My glue of choice back when I constructed the trestle, was white glue.  White glue is normally not waterproof, and I hoped that this was the type I had used.  Carefully, I applied water to the joint, and waited, applying some more water as soon as the first lot disappeared into the wood.  After around 5 minutes, the glue started to “go white” at the join, and with some careful pressure, the piers separated from the bridge deck. 

2 timber piers removed.  The plastic squeeze tube was ideal to get the water exactly where it was needed

All timber piers separated from the bridge deck.  Now the construction can start

Ironbark Models suggested and provided plans for a jig to make up your own timber trestle piers. 

Nest stage is to complete modelling the concrete abutments, and this will also set the rail height.  The subroadbed will then be built up to this height, prior to fitting the unnamed stream timber abutments.  Once the first one is in, then I will know the positioning for the other timber abutment.
Hopefully my next post will show a lot more progress.   Happy modelling.

Wednesday, 5 September 2018

Kyeamba Creek Bridge



The Kyeamba creek flows from the hills near the Hume Hwy south-west of Tarcutta, (near the Tumbarumba road intersection) for a distance of 66km before ending up in the Murrumbidgee River.  The Tumbarumba railway branchline crosses the creek just west of Ladysmith.


Kyeamba creek is but a muddy puddle in March 2017.  Whilst I was not able to actually measure the rail height above the water, I have estimated it at 21 feet.
Another shot of Kyeamba creek, photographed from the bridge, showing a typical creek bank, and vegetation

The Kyeamba Creek bridge is a 6 x 24’ span NSW timber trestle, with concrete abutments.  A small tributary of Kyeamba creek is crossed by a 3 x 24’ span trestle close by the main bridge.   

The last trains passed over the bridge in the late 1980s.  The bridge fell into disuse, although there was a later failed proposal from Tumba Rail to reopen this section for Trike rides.    It was last year, before I actually got to inspect these bridges.   My visit to the main bridge was unfortunately cut short, as I had disturbed a wasp nest, and they were not too pleased with the intruder, forcing me to make a tactical retreat.
Looking towards Ladysmith.  Checkrails are prominent., and also are spiked directly onto the sleepers, rather than on sleeper plates - similar to the Murrumbidgee River bridge.   The shed on the righthand side is part of the automatic water flow measuring system on Kyeamba Creek, used by the Bureau of Meteorology.

The first pier of the bridge holds the rail approximately 8 feet above the ground.  The ladder is part of the automatic water flow measuring system.  The wasp nest is hidden under the sleepers close to the ladder.  

The concrete abutment



The small tributary trestle was in far worse condition then the main bridge.  One of the embankments had been washed out in the big storms of 2016, and the rails had been left dangling in mid air.  But there was enough left to see what once was  present. 

The small 3 span trestle around 200 metres to the west of the main trestle.  This unnamed stream had caused a significant wash-a-way in the storms of 2016 

Closeup of the damage.  The main railway support piers survived but the embankment, and its supports had been washed away, leaving only the stumps.  The rail, and a few of the sleepers have been left suspended in mid air

The pair of intermediate piers are resting on concrete plinths, and these look in good condition

The timber abutment at the other end of the trestle is also collapsing, but 30 years since the last train, and probably over 40 years of no maintenance, this is understandable


Many years ago, I bought the Ironbark models NSW trestle kit and extension, and started construction of an eight span trestle bridge for a former layout.  I never finished this model, before a relocation forced me to tear the layout down.   However, I kept the part built kit.
My intention when designing the layout,  was to reuse, and complete the kit without modifications, as I like big spectacular bridges,  but the further I am heading up the prototypical accuracy modelling route, I realise that the bridge kit needs to be rebuilt.

2 spans and an abutment of the Ironbark models NSW Trestle kit that I built over 20 years ago.  I am hoping that I can use this section for the small tributary trestle, as the abutments look similar, and are the approximately the same height.  The longer pier will need to be replaced, rather than just cut down to size.  The reason for this is that the angled beams have been rebated into the round piers.  The other pier is really close to being right, but I will have to make a determination later


The Ironbark models kit has great diagrams to help with the construction of the trestle, but the Data Sheets (Sheet P4) is the reference for  the  24’ span NSWGR trestle bridge.  These plans contain all the bridge details I need, except the concrete abutments, and the height of the piers on the Kyeamba Creek bridge.  However, the end abutment drawing seems to be close to style found on the washed out tributary bridge. 
The first step was to draw up a diagram showing the concrete abutments, and pier heights. 

Sketch of the Kyeamba Creek trestle - showing details of the concrete abutments.  These sizes have been guestimated from photographs.


My next challenge will be to try and remove the trestle piers from the already constructed bridge deck, without doing too much damage to the deck, and construct the concrete abutments.
Until next time, happy modelling