The Big Picture Newsletter

July 2000 #10

This newsletter outlines the dimensions for NZ120 Module construction. There is a lot of interest in these as people are becoming more mobile and rooms seem to be getting smaller. One module won't give you much running room but two together look more promising. I have built two at 1200mm by 600 with the theatre ends only at the outer ends. They only have a footprint of 600 by 600 when stood on end

together for storage.
We have tried some variations on these and have come up with a standard. I will put brief details here. The full description is six pages so if you want one, send a S.S.A.E to Andrew. Alternately there will be a copy on the web site for those with Intenet access. Operation of the modules is to be by DCC controllers and so I have included a description of the modifications for DCC safe points and notes on decoder installation in the Dash 8 and SD7/9 chassis...Rod

Short Module Physical Specifications :-
a) Length/shape - Any, as long as the interconnecting ends conform to the parameters below.
b) Depth - 600mm deep at the ends (front to back)
c) Track Height - 1200mm from floor level to the top of the rail. This is the reference for all measurements.
d) Framework - Dressed timber, 65 x 19mm (75 x 25 nominal) Panels 4.5 / 6mm MDF or similar.
e) End Panel Height - 300mm above rail top,
f) Backscene Panel - no more than 500mm from the front of the module and as high as the the end panels.
g) Joining method - the Ends are to be ‘G’ clamped - no pegs.
h) Front Track location - 100mm in from the front edge of module to outside edge of front railhead, laid right up flush with the end.

j) Return (rear) track - 445mm from track front edge to the front track front edge. (545mm from the front of the module), laid to 62mm from the end and joined to the next module with a short Atlas track section.
k)Track straight - for 100mm from edge of the module. Also maximum Mainline Grade of 2 %
l) Legs - Attached at the left end, min size 50x25 DAR, braced for stability and adjustable by +/- 10mm.
m) Mountain track - A future option If required, 150mm above rear rail. This track should be located directly above the return track. Much more detail available on the NZ120 web site.

The pictures that are on the printed newsletter are on the website at

http://homepages.paradise.net.nz/~rdmurg/nz120/ and the full writeup at

http://homepages.paradise.net.nz/~rdmurg/nz120/NZ120modulestandards.htm

DCC safe points.
Peco and other “N” scale points can cause problems when a passing train’s wheels short between the running rail and the inactive blade rail. This is particularly so in Peco Finescale points as the blades are quite light and flex more than the standard point so reducing the gap to the running rail. DCC safe modification ties the blade rails and part of the next (closure) rail to the adjacent running rail so there can be no short circuit. The frog is isolated from these by making an extra cut in the rails about 17 to 20 mm from the frog rail point toward the toe of the point. The bottoms of the rails are exposed by cutting away the plastic between the sleepers and some light flexible wire is soldered from the running rail to the closure and then down to the blade. The frog power is supplied through a switch attached to the throw-bar in the usual way.

DCC decoder installation. Most Bachmann loco’s can be modified to accept a DCC decoder.

The power from the rails must only go to the decoder input. Motor power must come only from the decoder output. So the motor to chassis connection has to be broken and the motor brushes isolated and made accessible for the new wires. The body has to be removed and the chassis will need to be dismantled and parts ground away to give clearance.

First measure the hole the chassis has to go into and measure up the decoder. The length can be a problem and the height may be too high to fit between the chassis and the body top. I have had to cut some of the chassis away to get decoders in.
Dash-8 (Dx and Df, Digitrax DN140 ) decoders are fitted on the step at the rear of the chassis after a little metal is cut away toward the screw. The top is filed to allow the wires to run through. Take the motor out and observe where the brushes touch the chassis sides. The chassis metal will have to be ground away and space made for the wires to come out. Glue some insulating material into the places where the brush holders might touch.
The SD7/9 (Dc) needs a DZ121 decoder and the rear weight block cut down for it to sit onto. Remove the black wire from the top brush and look for the metal tab coming from the other motor brush to a copper strip. This is hard to see but hold a knife beside the joint, heat it up with the soldering iron and when the solder melts slide the knife blade into the joint and it will keep the pieces apart while the solder cools. Glue a sliver of plastic between the two.
Temporarily solder the Orange and Grey wires onto the motor brushes - test the decoder at this stage by putting rail power onto the Red and Black wires and seeing if the wheels go the right way for forward, if not reverse the connections. Shorten the brush wires to the correct size and solder them onto the brushes. Solder the red and black wires to copper tabs on either side of a chassis screw. Check with a meter that there is no connection between the brushes and the chassis sides. This will kill the decoder. Connect 16 volt bulbs or LEDs and resistors to the function wires, if you wish or tie down the extra wires out of the way. Test and install in the body. A similar procedure will apply to most conversions.

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Mail to:
Andrew Wells at Chosen Scale Etch Cetera, 16B Griffin Avenue,
Epson, Auckland, New Zealand.

Rod Murgatroyd at 139 Pinehaven Road, Upper Hutt, New Zealand 6007

Graham Baker at 67 Nelson Quay Cobden Greymouth
Web Sites: http://www.ozemail.com.au/~abwells/nz120.html
or my new one at: http://homepages.paradise.net.nz/~rdmurg/

Email to:
Andrew at <andrewwe @ advantagegroup.co.nz>
Rod at <railmodel @ FSmail.net>
Graham at <greytrainz @ xtra.co.nz>

Rod Murgatroyd...visit the NZ120 web sites at:

www.ozemail.com.au/~abwells/nz120.html Andrew Wells Etch Cetera.

http://homepages/paradise.net.nz/~rdmurg Railmodel Productes site.

Newsletter #10 Photos

My left hand module The framing is visible including the cross braces and the corner bracing. The backscene ends 500mm from the front and the left panel will join to the next module.
This is the two ends joined together with the front rail and the 'hole in the wall' visible. Trees, hills, a tunnel or other subdifuse will have to be used to disguise this. The mountain track comes onto the module above the return track and has to divert through the backscene to be visible.
The joint at the rear. Note I have inset the rear frame member to support the backscene and the return track will be supported on outriggers screwed to it. Return track support width must be 100mm to allow for trains falling over. An outer fence can be added to provide more protection against falling on the floor.
SD7/9 with motor brush connectors removed from the body pickup points. The Dash 8 needs metal removed from around it's brushes and a gap made for the wires to exit from the motor cage.
Peco points made DCC safe. Cut the closure rails where indicated. On the underside,
wire the blade, to closure, to stock rail with a flexible (fine) wire. Wire from the frog jumpers to a switch as normal to get the correct power to the frog rail. Insulate the track past the frog.
Rod Murgatroyd July 2000