Thursday 23 November 2017

A Yard Crane for Tumbarumba

Way back in 1993, Stephen Johnson Models were offering a NSWGR 5 Ton yard crane kit for $55.  “Just what I need” when I bought the kit, although in 1993, I had little idea that it would take me another 24 years to actually build it.
Photo of the yard crane at Tarcutta (photo supplied by Pauil F)

The kit consists of 2 small etch brass frets, some lost wax castings, wire, rail, angle brass, 4 resin blocks, a set of instructions, and 3 resin jigs to assist in the construction.

  A review of the kit was in issue 179 (April 1993) of AMRM. (Thanks James).  This kit has a reputation of being difficult to build. The reputation is well earned.

As is my normal approach, I try and find as much information as possible.  Unfortunately, I had failed to photograph the full crane at Tumbarumba when I was there in 1980.  Greg Edwards Data sheets do have a HO diagram of the crane, but the details of the winch, and gearing was unclear. All is not lost.  These cranes can still be found in various locations, so  made a 55km trip out to Ganmain a few months ago, and photographed the 5 ton crane there.

Ganmain 5 ton Yard crane

After I started the build, Paul F sent me a good picture of the Tarcutta 5 ton crane pictured above.  As Tarcutta is on the Tumbarumba line, it might have been similar to the Tumbarumba crane. Disappointingly, the picture shows the “other” style of 5 ton crane used in NSWGR, which is a hint that the Tumbarumba Crane might also be this style, and not the kit version. But, these are the risks one takes.

Bob S (see the SCR blog link), also sent me some scanned  diagrams of the NSWGR crane from the railway archives.  These diagrams showed the winch and gearing in large scale.   These diagrams proved invaluable. Thanks Bob

Use of the jigs to build the “A” frames

Lower winch attached to one of the A frames

Anticipating a future step, I made winch spool rotatable.   However, I ran into a lot of problems in getting the top beams, and A frame assembled.  In retrospect, I should have made a jig to hold both A frames vertical, and not skewed.  Once the A frames are firmly held in correct alignment, then solder the pair of beams on top, and then add the cross bracing.  I won’t go into the method I used, but it almost resulted in the whole lot being launched into orbit
Even the bracket for the upper gearing was a significant exercise in alignment of the parts. 

Crane basically assembled.  Still have the set of steps to add to one of the A frame pillars, and the attachment of the ropes, and chains

Attaching the ropes, and chains was at best frustrating.  The instructions advise twisting the fine copper wire supplied together to simulate the chain.  This was straight forward, and from a distance, doesn’t look too bad.  Looking at Bob’s supplied plan, the upper chain goes from the trolley, and winds above the pulley, then go over the trolley to the other end, when it returns to the trolley.  (The instructions suggest the chain should go around the pulleys in the other direction, and the chain is hidden behind the top beams).  The chain descending to the bottom was also just a matter of getting the length right.  However, the brass wire supplied for the winch to the hook gave me lots of problems.  Basically the wire supplied was too hard, and fractured easily.   Solution straight forward.  I substituted some softer “tinned”copper  wire –taken from stripped insulated hookup wire.  This wire bent easily, and allowed me to wind it around the winch spool

Finished, painted with sellf-etch black, and weathered with my pastel rust powders.  Although the chains might have to be reworked if I find chains fine enough

Now that I have this crane built, I discover that there was also a crane at Ladysmith.  So unless another SJM kit appears, I might just have to throw money at the problem, and acquire the 5 ton crane model being sold by “The Model Railroad Craftsman” at Blacktown (even though this has an error in the bracket for the winch being on the inside of the “A frame”, and not the outside.  Who is going to be this nit picking?).  

Picture of the MRRC crane

Friday 10 November 2017

Bomen Station Building Plans

Over many decades, I have been acquiring information to aid my prototype modelling.  Unfortunately, the Bomen Station plans have not surfaced.   My understanding is that Bomen station building is unique in NSW, so it would be highly doubtful that a kit would ever be produced.  Drawing my own plans seemed the best way forward.

Bomen station was commissioned as an important station – being the temporary terminus of the Southern line in 1878, and the location of the town of North Wagga Wagga..  But soon after the station was built, the townsfolk drifted to South Wagga Wagga.   Bomen station remained as a staff exchange point, site of the Wagga meatworks, and for general goods.   I covered this in my earlier blog post
A trip to Bomen, armed with my digital camera was the first step.  After taking 50 or so pictures, I returned home, and printed 10.  Armed with these pictures, pen, and tape measure, I returned to Bomen and recorded these measurements on my pictures.  I used metric measurements, as this makes the reduction simple on a drawing

In 1974, I did Tech Drawing at high school, and I found these skills useful.  Whilst I probably should be using CAD, I spend too much time on the computer now, so it was good to get out my set squares, rulers, pencil, eraser, and paper, find a sunny spot, and do some drawings.  Before I started, I added up all the measurements, and compared the 2 sides, and the front and back.  I was out by 1cm on the sides, and 6cm on the front, and rear measurements.  This is well under 1% error, and reassured me that I had not made any major measurement errors.   It took around 6 hours, spent over 2 weeks to finish the plans. 

As I drew them to scale 1:100, a trip to Junee Library, to use their enlarging photocopier made short work of the conversion to 1:87.  My plans will not win any awards, but are suitable for marking out the sides, front and back on styrene brick sheet.  The one aspect that I know is wrong, is the roof. I initially thought a 30 degree slope was close, but the 25 degree for the end drawings is closer again.  I also have the chimneys in slightly the wrong spot – so I will have to go back to Bomen, and really look

What struck me is how big the station will be.  The HO scale footprint of the main building is 30cm x 13cm, and this is not including the Toilet block, and signal box (or indeed the car park at the rear).    I should be able to construct the station full size, however, I will do some more detailed track planning of the Bomen area to confirm I can fit everything in without the baseboards being too wide.
Now comes the “fun” part – actually building the station.

Happy Modelling.