Saturday 19 October 2019

Bethungra Loop - in "N" scale pt2

Having spent last weekend at the National "N Scale" convention in Canberra, my progress on Bethungra was slowed.  I had hoped to get all the track down for instance.  Still, the delay in the layout build was fully compensated with inspiration at the Convention.

The Convention may have a focus in N scale, but there were many non scale specific clinic topics, as well as some world class modelling to keep the delegates entertained.  Quite good retail support, with Peter Boorman's Workshops, Pallas Hobbies, and Badger Bits to name a few.  Clinics that I attended included  NSW stock yards, plug casting, weathering USA freight wagons, styrene buildings, lightweight module design and an interesting one from Greg Edwards on some of the background into the color images in the recent "NSW Railways in Colour" book.  The highlight though, for me, and most others was Ross Balderson's Newcastle 1899, which although not yet finished, actually had moving trains
Excellence in N scale - Ross Balderson's Newcastle 1899 has taken 7 years of construction to reach this point, but every building, vehicle (and ship) is a faithful representation of the original, many constructed based from period photographs

One of the side benefits of the convention, was I was able to purchase 2 x 1KG packets of N scale ballast (Bombo quarry), some will get used on Bethungra.  I even won a  brand new "Micro Trains" USA N scale boxcar as a lucky door prize - although I don't have a loco with the right coupling to immediately test on Bethungra.  Micro Trains (USA) was a major sponsor of the convention.

The next N scale convention is in Sydney in 2021.


Benchwork construction for the extension of Bethungra was a little challenging.  Unlike most exhibition layouts where module sections are bolted together, I needed a rise in elevation of the tracks on the extension.  The tracks would also cross the section boundary not on the flat - one track would have a falling gradient, the other a rising gradient. Anyway, best I illustrate the process with pictures.

Way back in 1985, the ACT Model Railway society built a module layout, that used a leg leveling system that used "T" nuts and bolts into the bottom of the legs.  I was the owner of 2 of these modules.  After 20 years of disuse, I thought they would make a contribution to Bethungra.  

I constructed an interface on top of the existing benchwork.  The T nuts and bolt were attached to the other side, leaving the bolt ends exposed.  These bolts don't extend to the edge of the benchwork, so they shouldn't snag during transportation of the sections.  And the spacing also allows the extension benchwork to rest on the existing benchwork, and then wiggled onto the end, and slid into position.  The wing nuts and washers tighten the join.  Note the profile variations for the trackbed at the ed
After adding the extension, here is the view from the current benchwork

Another angle.  The bolt is tightly forced into the T nut - it is unlikely to work loose in the few times the layout will be unbolted.  

The other pair of legs, and the new timber frame.  Using the existing benchwork as one end, makes assembly easy - although I have not added any leg folding mechanism.  The section will be laid on its side during transport.  The legs are lightly braced.  One other thing I would like to say, is that the plywood top was donated by the "Mens Shed", who gave me  more sheets that I needed for this project, although they will be handy when it comes to the Wagga layout.  To ease my guilt, I am supplying all the other timber and hardware to the Broadway Museum at no charge

I did not want to introduce an vertical "kink" in the join across the benchwork.  A metal ruler allowed me to see any variation.   The "down" track has not yet been attached

After cork and track had been installed, I added PCB slabs to the track on both sides of the join, secured with screws, before cutting.  The screws will enable some adjustments of the track  Up.down, left right to remove any variation.  And the PCB could also host checkrails, although testing has not needed them so far.  Note the screws came out of old VHS Cassette cases - I never throw away something that could be re-purposed 
Buried in one of my boxes, I had a pair of N scale through deck girders.  (Could be Peco).  A section of 0.040 thick styrene was added, and I had my deck bridge.  Tested for size.  Both the upper and lower track was not secured at this time.

On the workbench, some simple abutments were cut, again from 0.040 styrene sheet

After a bit of timber sculpting, the bridge is in.  The lower trackbed is still floating, as I wanted the upper track fixed first.  There is a 40mm clearance.

Cork added to the extension.  I cut my HO cork down the middle, which allows me to bend it to tight radius, AND allows me to align on the previously made pencil line radius - thus retaining the original centerline geometry 

Track down.  All flextrack.  It would be easier to use set radius curves for this, as the flextrack tends to kink when connecting them on curves.  However, with careful positioning of the joins, this can be minimized.  My test train is also pictured.  The F7 (or F9) is missing its shell, but runs OK.  The coil wagons were from my scrapbox, but good for this purpose.  I have been running the test train up and down the spiral, often at speed, and derailments were few, track fixed, and tested some more.   
During the convention, I spoke to a few modellers about my excursion into N scale.  Much to my amazement, an article on the original Bethungra Layout in the Broadway Museum had been published in an "N scale Modelling in Australia" magazine a few years ago.  A link to that issue is below.

Until next time.  Happy modelling

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