Thursday, 27 June 2019

Signal Box construction - pt 1

Signal box construction - Part 1

Progress on the Wagga Wagga, and Bomen signal boxes has been steady, although the  time expended on searching for kits, styrene parts, and coming up some alternate assembly  methods to get around some inadequate kit parts is frustrating.

LVR 3026 approaches Wagga's signal box

One of the challenges to create a model, is to accurately size the model from photographs.  Whilst Greg Edwards Lineside data sheet S3 gives the general sizes,  I drew up 2 plans

Wagga Wagga signal box plan.  There were some errors on this diagram - information from Bob Taaffe gave the clapboard at 7.5" (not 6") and my guess on the width of the box was out by about 12".
Bomen signal box plan.

I guess that the hardest part of this project would be the signal box windows.  I was unable to find any Grandt line windows in my accumulations that could be modified, and lacking the experience to design on 3D, I made up some close enough representations from raw styrene strips.  I hope these pictures are adequate to see my progress.

There are 5 window frames for the 2 signal boxes.  For the frames, I layered eight 10 thou thickness overlapping strips to form a rectangle.  Then another 4 styrene  strips to the inside to add some "bulk" to the frame. 
Adding the internal mullions.  The Bomen window frames are white, where the Wagga frames are coloured.  Using the NWSL chopper, cut up the specific styrene to the appropriate size.  Then, very carefully, position them on the clear styrene window, and glue by capillary action.  The smallest styrene strips I had were 0.010 x 0.020.  The Wagga windows were done second, and I made the windows so they could be positioned partially open. 
The 4 sides of the Bomen Box, together with windows.  The board construction was done with Evergreen styrene shapes"V Groove" 
Bomen box, basically assembled, with the roof added.  The roof is permanently attached to the walls to provide the structural stability, and to allow the interior to be kitted out as a separate project.  Note the  missing the 0.040 square styrene strips for the corners - a size I didn't have

My intention was always to have an interior.  Many decades ago, I had bought 2 boxes of signal box interiors.
The contents though were generally unsuitable.  There were 25 levers (5 shown), block shelf, a selection of block instruments, a gatewheel, stove, desk, chair, clock,phone, and a signalman.  A 20 lever frame made up from these parts would not fit inside the bomen box, so I put the interior on hold. 

Progress stalled for a bit, whilst I obtained the clapboard, and strip styrene, and a number of UnEEK signal box kits from the Rosehill exhibition.

I bought 5 packets.  Bomen had 17 levers, and Wagga 41 - making 58 needed.

I used 2 of the 12 lever baseplates for the Bomen interior.  Fitting the levers was a struggle - I used low-melt solder, although the solder joint was at best fragile, and broke many times as I added more and more levers

The 17 levers in place, and roughly painted.  The levers pulled are 1, 3, 4 and 8 - which is correct for a run through from Wagga to Junee on the mainline.  Colours blue for locks, red for signals, and black for pointwork.  
Assembly of the Wagga Wagga signal box was similar to Bomen.  After cutting out the 4 walls, I glued a angle to the inside edge to give extra support to the wall joint 

Fairly simple assembly on the workbench, with square.

The 0.040 x 0.040 square styrene added to the corners.  Note the writing on the rear wall.  Assembly of clapboard upside down would be extremely easy, and this was my way of preventing a "Murphy" problem
5 of the lever frame bases (64 levers worth) against the frame shows a dimension problem.  It then hit me, the Uneek baseplates are UNDERSIZED.  The spacing with the slots is around 3.5" scale inches, and not the almost 5" of the prototype.  This could be the reason why there are 2 uneek base plates for kit of 12 levers - and a spacing of levers then would be approx 7".  But a 7" spacing would also not fit the signal box, and visually look wrong.   Why is nothing in this hobby simple?   
To get around the fragile nature of the lever, I added a brass pin to the base.  Make a knife cut in the base of the lever, tin the point of the brass pin, and low melt solder the pin to the lever.  I have 41 levers to do

The baseplate replacement.  2 lengths of styrene strip laminated together  (0.040 for the bottom, a smaller width of 0.030 for the upper).  After shaping to a rounded shape, 56 slots were sawn with a razor saw 1.5mm apart, to a small depth
new baseplate added to the styrene floor of the Wagga signal box.  The new size fits the box a lot better.  Holes will be drilled in the baseplate slots as appropriate for the levers

Bomen Signal Box ready for paint.  the windows are held in place with Blue-tac.  A downpipe needs to be added after painting.

That's it for now.  But I will leave you with a picture from the mainline that is in the "to be modelled" area of my future layout.

A big time waster visited Junee/Wagga at the beginning of June 2019.  Here is 5917 running between Bomen, and Shepherds Siding.  Weather was perfect.   

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