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.   

Tuesday 11 June 2019

Wagga Wagga and Bomen Signal boxes

Wagga Wagga, and Bomen Signal boxes
The signal box, as the name suggests, is associated with the signalling.  Its purpose though is to control the operation of trains through the station in a safe manner.  It does that by interlocking the signals, pointwork, and controlling the access of trains onto the mainline and branchline with staffs or tokens
Both Wagga Wagga, and Bomen stations had signal boxes.    These boxes lasted until 1983, when they were removed after the introduction of CTC.

Wagga Wagga signal box

Original Wagga diagram, as displayed by the Wagga Wagga Rail Heritage Museum

The main Wagga box was a standard design skillion roofed structure, although much extended than most on the NSWGR railway system.  Excellent drawings of this general design are on Greg Edwards Data Sheet S3 – Platform signal boxes 1913.  As I have been unable to find the exact dimensions, I have guesstimated the size from photos.  Inside the box, there was a signal diagram, a blockshelf containing the repeater indicators,  a number (3)  staff instruments,  a large  lever frame, phone, plus heater, desk, chair, and other furniture.   It is with much regret that I never managed to look inside the Wagga signal box, as I have only found one inside photo.

Inside the Wagga Wagga signal box.  Note the block shelf and the missing levers.  The signal man is using a cloth to prevent marking the polished lever frame tops. Signalmen were an extremely proud bunch. Framed picture displayed by the Wagga Wagga Rail Heritage Museum

The lever frame at Wagga could accommodate 56 levers – although the reality was by 1983, only 41 levers remained functional.  2 others were painted white (out of use/spare), and the rest had either been removed, or never installed.
.tif diagram of Wagga Wagga in 1941 - on the ARHS Signal Diagram CD ROM

The Bomen signal box was also a skillion roof box, but unlike Wagga, the Bomen box was positioned on the platform.  Again, I have been unable to determine the size, and with far fewer pictures, more of a guess.  What is unusual about the Bomen box, is the window placement on the northern wall.  If the window was  positioned in the middle of the wall (as per normal design), the signalman’s view of the railway would be more obscured by the Bomen station building.  I have drawn a plan showing a double width window in this location, which may not be correct either.  My one photo is not clear one way or the other.

Bomen Station, looking north towards Shepherds Siding.  The signalbox looks like a standard platform box

An enlarged snippet of my slide of Bomen, showing the  signal box taken around 1981. The positioning of the window at the northern end is a lot closer to the front wall than standard - possibly to allow a better view of the mainline.  I cannot determine if this window was this width, or double width.  
Signal box diagram as it appeared inside the signal box.  Picture from the internet
.tif diagram of Bomen dated 1952 (taken from the ARHS Signal diagram CD ROM)
Staff exchange platform at Bomen.  A staff was the authorisation needed by the train driver to access a section of railway line.  A train would pass this point, and the signalman would collect the staff from the earlier section, and exchange it with the staff for the next section.  The staff recovered would then be "planted" inside a staff instrument, which would make the section available for another train.  Read on further for more detail.

Miniature Staff instrument, (incomplete) on a plinth displayed at the Junee Roundhouse museum. Both Wagga and Bomen signal boxes had staff instruments.  The instrument had provision for 40 staffs.  The "hoop" resting on top of the staff was important, as the staff could be secured in it - and it was easier to transfer the staff at speed by capturing the hoop on an outstretched arm.  Unlike a relay baton. 
A miniature "C" pattern staff from my own collection.  Station names were stamped on each side, along with the pattern letter.  This particular staff was previously used in Queensland, but the design was identical to NSW

A selection of block shelf instruments again from my own collection
Lever Frame at Cooma is one of the few complete examples surviving in NSW.  The blockshelf has one instrument on it.  Note the levers have a descriptive name, as well as the number.  The colours are red for signals, blue for locks and keys, and black for pointwork
Another trinket in my collection. The lever frame plate is solid brass, and often polished. 

Inside Harden North signal box, during an ARHS tour in the 1990s.  The white levers indicates that the levers have been taken out of service
A very sad display at the Thirlmere Railway Museum.  Not only was it awkwardly placed in the main hall, the levers and the number plates were obviously wrong – eg. with a red lever (#5) with description :”Key for..”  A Key lever would be blue.  The interlocking was mostly missing, and non-functional.  There were NO signal box accessories, and I would suggest that a far better display could have been made by copying the interior of the Cooma signal box, and placing it up against a wall.

The lever frame at Wagga could accommodate 56 levers – although the reality was by 1983, only 41 levers remained functional.  2 others were painted white (out of use/spare), and the rest had either been removed, or never installed.

note: the model is scaled approximately 1:10 scale, although the spacing between the levers is greater than the prototypes approx 5” spacing to accommodate the 1:1 scale operators hands.

The first model constructed specific for my Wagga layout was a 56 lever cam and tappet frame.  This was built over a few years when I was living in Queanbeyan, with guidance from Tony Kociuba (Mackenzie in H.O.Lland) .  My frame is not yet completed.  It has provision for mechanical interlocking just like the prototype (and I will spare you the details – it is not for the faint hearted.  If you are interested, the “links” from the H.O.Lland web site has some excellent examples).  At the rear of the frame, I also need to install electrical slide switches, which will activate the servo motors for the signals and pointwork. Tony recommended that I install all levers, just in case I needed some extra functions later.

The Bomen frame was a more modest 20 levers, and whilst I do not have a frame built, I may commission Dale Richards to build it for me.   The other aspect of interest is the “staff exchange platform” – which was used by the signalman to exchange staffs giving permission to the train driver to enter the next section of line.  In my operation, I hope to employ staff working over the Murrumbidgee River bridge

I have made a start on constructing the Bomen signal box.  More details in a future blog post.  But here is a teaser picture

The 4 walls for Bomen Signal Box, and some scratchbuilt windows

If you have read this far, and are wanting far more information on signal boxes, may I recommend that you contact Bob Taaffe.  Bob Taaffe has done a number of presentations at the Modelling the Railways of NSW, and is extremely knowledgeable about NSW signal boxes, and workings.  Bob is currently about to publish (in 4 volumes) a comprehensive guide to signal boxes throughout NSW.  He is presently taking orders for the first volume, but you will need to be quick, as the cutoff is July 1st 2019. Bob is self publishing the book, so  it is unlikely that the book will be re-run.  Price including postage was $110.  Contact Bob at

Whilst on many home layouts, the signal box is an interesting piece of architecture, I am hoping to use them in a very prototypical manner.