Z Scale HCD

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Re: Z Scale HCD

Postby Chaz » Thu Jan 19, 2012 10:28 pm

Hi Gary,

You are correct the tracks are configured as a cross over. But you said they were only for show. What I suggest is using the middle track as a passing siding. That means that the longest train has to fit completely on the middle track. The key is powering the center track from one power routing turnout at a time. That is, this passing siding could be used by trains running East on the Red track and running West on the Blue track, but crossing between Blue and Red is not allowed.

On my layout, the shared passing siding eliminates one track at the bottom of the layout. The yard's Arrival/Departure track is now dedicated and not shared.

I too want to add signals...which I know very little about. I assume that means detection, lights and track control around Suicide Junction to eliminate collisions.

Chaz
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Re: Z Scale HCD

Postby ozman2009 » Fri Jan 20, 2012 12:01 am

Hi Chaz

I had another close look at the layout this morning and it hit me that Suicide Junction is a work of genius. Of course it's only practical with Rokuhan track.

In 2001 Milady and I travelled from Rome to Naples by train and I noticed that the type of passing track you mentioned was quite common, so the idea has been endorsed by the prototype. It should be possible to wire up the turnouts to prevent trains from crossing from the red to the blue tracks and vice versa. Also, given the larger selection of curves that you get with Rokuhan, the centre passing track could be on a curve.

An old saying is that "the devil is in the details" and it will be a devil of a job to design the signalling circuits for that junction. The much simpler part will be providing a signal box (tower) there. A prototypical junction like that would simply have to have a tower.
Gary
Z Scale
Sydney, Australia
"Never let the prototype get in the way of a good layout".
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Re: Z Scale HCD

Postby Chaz » Fri Jan 20, 2012 1:59 am

Hi Gary,

I don't know about genius. I've seen similar designs with longer paths to bypass the crossings. I think they look better. I just ran out of room and had to compress the junction to the smallest size to get the slopes down to 3%. Any track manufacturer with crossings and turnouts with the same angles and lengths will work. You can create the same junction with LGB track in G scale and Kato track in N scale.

Let me think about the detection logic around the junction.

Chaz
You can have it fast, cheap or good...pick two.
Chaz
 
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Re: Z Scale HCD

Postby ozman2009 » Fri Jan 20, 2012 3:22 am

Suicide Junction LOOKS very complex, the sort of thing you see at yard or major station throats. I think it's very clever because trains can either continue on around the layout, or reverse direction, all without polarity issues and in a very compact area. To do the same with Marklin track you'd have to do a lot of kitbashing because they are "power everywhere" (MTL don't make crossings).

Lights: Both Marklin and Viessmann make German-style colour light signals in Z scale, and I believe that you can get US-style searchlight signals.

Track power: There are four approaches to the junction and each one of those could be controlled by an isolated section of track with it's own feeder that could be switched on or off. All of Rokuhan's 110mm straight sections take a feeder and they also make isolating track joiners.

Switching logic: I suppose it could be done with analogue gear, but would there be scope for using a DCC controller? Expensive yes, but maybe easier.

Detection: I'm not at all keen on the idea of affixing little magnets to the underside of locos. Viessmann make a track block occupancy detector, which might do the job, or maybe Rokuhan will come up with an equivalent to the Marklin circuit tracks.
Gary
Z Scale
Sydney, Australia
"Never let the prototype get in the way of a good layout".
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Re: Z Scale HCD

Postby Chaz » Fri Jan 20, 2012 5:01 am

Gary,

This is a pretty good explanation of how to protect a double crossing. http://www.azatrax.com/track-crossing-protection.html

If I understand this implementation, you need four, above track detectors and two DPDT relays to interrupt power to the tracks. Each detector spans a pair of tracks. There are two detectors on the East/West tracks and two on the North/South tracks. The distance between detectors has to be less than the length of the shortest train and far enough apart to protect the cross traffic. Unfortunately, 13 degree crossings make the shortest train pretty long. I calculate 238 feet.

Azatrax also makes detectors that indicate direction as well as occupancy.

Chaz
You can have it fast, cheap or good...pick two.
Chaz
 
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Joined: Wed Jun 08, 2011 8:40 am

Re: Z Scale HCD

Postby ozman2009 » Fri Jan 20, 2012 12:46 pm

Thanks for the link. Which track planning software do you use? I use RailModeller because it runs on the Mac.
Gary
Z Scale
Sydney, Australia
"Never let the prototype get in the way of a good layout".
ozman2009
 
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Re: Z Scale HCD

Postby Chaz » Fri Jan 20, 2012 3:30 pm

I use AnyRail. It just felt right.
You can have it fast, cheap or good...pick two.
Chaz
 
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Re: Z Scale HCD

Postby Chaz » Sat Jan 21, 2012 9:53 pm

Gary,

This is my final version. I added a nice long passing siding and some more industries. The passing siding is technically a reversing loop. You change the polarity on the siding with the power routing turnouts. Of course, the train will have to be stopped first.

Chaz
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You can have it fast, cheap or good...pick two.
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Re: Z Scale HCD

Postby ozman2009 » Sun Jan 22, 2012 6:28 am

Hi Chaz

Thanks for the updated version. In the case of the Italian passing tracks I mentioned before (between Rome and Naples) it seemed that the centre track was used by freight trains being overtaken, while the overtaking trains used the two outside tracks. Also, I have a Marklin Z scale track planning book with a similar arrangement in one layout. I think this would fit in quite well with your plan - ie that the train would have to be stopped first.

A suggestion: If you were to use the passing track that way for trains running counter-clockwise, then if you were to reverse the crossover between the blue and centre tracks in the bottom left corner (ie have two left turnouts instead of two right), then you could more easily run that train into the yard.
Gary
Z Scale
Sydney, Australia
"Never let the prototype get in the way of a good layout".
ozman2009
 
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