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Single direction points


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A while ago on RMWeb - perhaps even in the days of RMWeb2 - someone put up a modification to a point to make the point uni-directional.

 

The original point was modified so that a loco entering the heel of the point would always go straight bat a loco entering either toe would still pass through the point without derailing. The important thing being that the point required no actual switching.

 

The idea was put into practice on a reversing loop so that a train would enter and exit the loop without the need to change the point and using just diodes to control the electrics.

 

I am looking at the possibility of a "whimsy" using two of these points in a circle to make a bi-directional passing loop.

 

The questions to be answered are:

1. I cannot find the original article. Can anyone else remember where it was?

2. Could the modification be done with Peco OO9 points

3. Could it be done set to the curved direction or even with a Y-point.

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A while ago on RMWeb - perhaps even in the days of RMWeb2 - someone put up a modification to a point to make the point uni-directional.

 

The original point was modified so that a loco entering the heel of the point would always go straight bat a loco entering either toe would still pass through the point without derailing. The important thing being that the point required no actual switching.

 

The idea was put into practice on a reversing loop so that a train would enter and exit the loop without the need to change the point and using just diodes to control the electrics.

 

I am looking at the possibility of a "whimsy" using two of these points in a circle to make a bi-directional passing loop.

 

The questions to be answered are:

1. I cannot find the original article. Can anyone else remember where it was?

2. Could the modification be done with Peco OO9 points

3. Could it be done set to the curved direction or even with a Y-point.

 

It was on Eldavo's Cramdin Yard, Kenton.... Page 6

 

http://www.rmweb.co.uk/community/index.php/topic/1207-cramdin-yard/page__hl__cramdin__st__125

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Thanks Gordon, but that is not quite the same thing. In the one I was referring to the point is locked solid with no springing.

 

Although springing in one direction will work for OO, I don't think it will work in OO9 I seem to remember that it was this reason why the mod was made in the first place. The trucks in OO9 just do not have the weight to overcome the spring and will either be launched into space or risk switching back and shorting the circuit.

 

The modification involved soldering the switch rails to the stock rails and some cutting and I think re-wiring.

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Hi Kenton,

 

I did something similar on a SNCF N gauge layout with Peco Insulfrog points. The trailing points in the fiddle yard were all modified to be unidirectional so that only the entry points needed switching.

 

I removed the tiebar and springing mechanism, cut back the switching rails to allow the wheel flanges to clear and created a gap in the sleeper base nearer the frog.I then soldered a length of copper pax sleeper strip as a 'fixed' tiebar in the gap. This was suitably gapped to prevent shorting.

 

When it worked, it worked well even with Fleischmann N gauge RoLa stock with minute wheels. The problems I found were generally with stock uncoupling - due to light stock and coupler variances - which was then more of a pain to re-couple as you can't simply reverse the loco!!

 

Your application sounds ideal - best of luck!

 

Bruce

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3. Could it be done set to the curved direction or even with a Y-point.

I would be pessimistic about the reliability, especially with the rather coarse N wheel standard. The 'straight ahead' setting is working with the physical law that a moving object keeps going in a straight line unless there is an opposing force. For a moving object to take a curved path requires continuous application of force to produce the acceleration that following a curved path represents. The check rail has to be gapped to allow the flange through on the reverse route, and that gap means loss of force acting on the flange rear of the vehicle on the forward curved route.

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The check rail has to be gapped to allow the flange through on the reverse route

Check rail?

As said, I thought the switch rails were soldered to their respective stock rails. But then I realise that nothing would get through so that some cuts would need to be made to let the flanges of both wheels through. What I can't remember is how and where, how big these gaps should be made. When I imagine it on a point in front of me all I can see is potential derailment.

 

The wheels would certainly be coarse standard 9mm - it will be OO9 and I'm pretty sure the original post was also OO9

 

If it can't be done for the curved route as default (therefore not Y either) that isn't too big a deal - I'll just have to dent the circle shape.

 

Reliability is a must as the whole thing is switch on and leave it to run, two trains going in opposite directions.

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Kenton - I think the item you are searching for was on a now defunct, geocities website called the Dynamite Canyon Tramway. I know the owner, and will try to get you a link. - the system he uses works very well, and watching trains run quite happily through a solidly soldered turnout, tends to make the jaw drop

 

Edit - email sent to him

 

2nd edit - I have just found a PDF via an alternative route - it is the same article that Smokebox was trying to link you to.

 

http://www.zelmeroz....amiteCanyon.pdf

 

Note, as he shows, that it is quite suitable for N or NG as well as HO

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Two replies from John which I am posting - he has read your posts, but isn't a member

 

Dear Jack,

 

Yes, Geocities went belly-up late last year,

 

http://latimesblogs....es-closing.html

 

and unfortunately my websites for Broughton Vale Tramway, Dynamite Canyon Tramway, and Camp4 went with it…

 

Lynn Zelmer offered to host a selection of the pics and a PDF version of the text for each site. Unless/until I can gather up the motivation and cash to buy some webspace, I guess it’s a do-able way of keeping the info available…

 

You can get the DCT info HERE

 

http://www.zelmeroz....amiteCanyon.pdf

 

In answer to the questions posed:

1 – See above. I’m happy to answer any further questions if needs be J

2 – Yes, it most certainly will work for OO9/HOn30, and would probably work for N gauge as well

3 – It _MAY_ work with a curved point, with Toe>Heel preference being give to the OUTSIDE/Wider radii route thru the turnout.

(IE the route which presents the least “natural deflection resistance†to a wheelset).

 

It would NOT work with a Y point, as it relies on the inherent nature/geometry of a RR wheelset to want to “go straightâ€.

An equal-angle Y turnout has no “natural geometric pathâ€, with both routes presenting an equal amount of deflection to the wheelsets. L

 

If a Y point MUST be used, I’d recommend considering

- removing any centring spring/mechanism

- ensuring the turnout is Absolutely frictionless

(Shinohara and Atlas turnouts appear superior in this regard, as compared to PECO)

- and use a 0.010 phosphor-bronze wire as a “super light spring†to form a sprung turnout

(I recently did this for a friend in On30, using Atlas HO settrack turnouts).

 

Hope this Helps,

Happy to answer any detail questions…

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

****************************************************************

 

 

 

Dear Jack,

 

Glad to see you found it… J

 

I note that the Requester wants to run ‘2 trains in opposing directions’.

 

I have used 2 of the “one way†turnouts to create cycling “passing loop†layout with 2 X analog DC trains which never collide.

See attached image.

 

Given 2 (TWO) such passing loops, on opposite sides of a circle,

and a “dumb timerâ€/reverser with enough of a delay for teach train to make it from one passing loop to the other,

you could achieve “2 trains circling in opposite directions around a circuit,

passing each other at each passing loop…â€

 

Just thinking out loud…

 

Happy Modelling,

Prof K

 

 

 

 

post-6688-12724637344.jpg

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Jack, thanks very much. That looks very familiar. I did think it was on RMWeb (post of a member's layout) but guess there was some confusion in my mind.

 

I don't suppose a closer shot of the joins and cuts is available, or he could post further comment here? ;)

 

I note the emphatic "electrofrog need not apply" so I guess the use of Peco OO9 track is going to be a no-no then. Pity.

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If you are using the point for a reverse loop, contrary to what the article says there is no reason not to use a live frog point. You just need to make sure that your section break is between the switch rails and the frog while you are modifying the point.

 

 

 

 

 

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Jack, thanks very much. That looks very familiar. I did think it was on RMWeb (post of a member's layout) but guess there was some confusion in my mind.

 

I don't suppose a closer shot of the joins and cuts is available, or he could post further comment here? wink.gif

 

I note the emphatic "electrofrog need not apply" so I guess the use of Peco OO9 track is going to be a no-no then. Pity.

 

You could always convert the OO9 point to insulfrog, or use an N gauge point - you should have a PM so you can converse direct

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Further post from John

 

Dear Jack,

 

 

Thanks for the heads-up and posting. If Kenton absolutely insists on using PECO OO9 points, there’s nothing stopping him cutting an isolating gap, and rendering the metal frog “deadâ€.

 

The turnouts of DCT are PECO N-scale setrack units,

(curved diverging route),

 

So starting with an N-gauge donor point, and relaying it onto suitably-spaced wood sleepers is a very easy do-able option…

(did just this with BVT!)

 

The only big issue I can see is possibly the slow-speed crawl performance of smaller 0-4-0 NG locos and similar over the plastic frogs. But then again, that’s one of the reasons I swear by Graphite! J

(and 4 axle B-B diesels or 4-axle geared locos… J ).

 

I can’t get pics of the turnouts right now,

(It’s 12:17 here, and I need to get some sleep),

 

But I can get some pics in the next 24 hours or so,

 

Is there anything specific I need to shoot up close?

 

Happy Modelling,

 

Aim to Improve,

 

Prof K

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Further email from John

 

 

Suzie appears not to understand the concepts involved.(my suggestion would be respectfully to read back through the instructions carefully, and then try one for herself…)

Sure, you could cut some gaps ½ way between the soldered switchrails and the frog,But where would you put the gaps for the “stop block†which ensures the loco exiting the loop does NOT hit the ‘mainline’ and cause a short?

 

There are 2 (TWO) potential short circuit points to consider

- the frog and turnout contact points,

- And the mainline feeder track<> balloon loop toe

 

Anywho, You know and I know it works as described… J

 

G’night!

 

Happy Modelling,

 

Prof K

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I have read the article. Here is a little diagram to show you how I used to wire up a reverse loop for DC in the olden days with a live frog point.

 

post-7495-127246789279_thumb.gif

 

The orange lines show where the isolating breaks need to be, the power feed is on the red and black rails. The polarity can be switched any time that the train is in the section with blue and green rails. If the power feed polarity has not been switched by the time the train gets to the section fed with a diode, it will stop until the feed polarity is switched.

 

Notice that the green rail is common to both rails on the frog so there is no need for isolating joiners on the frog rails. Realistically the isolating gaps at the ends of the blue rails can be made with isolating joiners on the outer rails of the point, the isolating gaps can be staggered without any ill effects.

 

There is never any need for a dead frog.

 

 

 

 

 

 

 

 

 

 

 

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Thanks for the additional info Prof K and Jack for acting as intermediary.

 

I posted an edit to the previous post but it seems to have gone wayward while my PC was doing a routine backup.

 

So some of the additional questions are answered.

 

Following is the extremely simple track plan to attempt to clarify - I am a bit concerned about the use of insulfrog points as the locos will all be pretty light weight and short wheelbase.

murquick-mine_002.jpg

 

[Ed]. just edited the image to try to make the operation clear if it wasn't already.

Simply one train clockwise and one anticlockwise. No changes of polarity (probably run on a battery) the wires of one loco will be reversed or it will simply run backwards.

There are only three operating states:

A. block 1 isolated block 2 active

B. block 1 isolated block 2 isolated

C. block 1 active block 2 isolated

cycles through A/B/C/B/A/B... controlled by timers to allow (1-n) circuits and each train to return to its isolated block

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Suzie, on you diagram isn't there a short in the point vee (where the red touches blue)?

There are isolating breaks between red and blue shown by the orange lines. If you mean the red and black, then my earlier post applies:-

 

You just need to make sure that your section break is between the switch rails and the frog while you are modifying the point.

 

This will have to be done anyway and it is normal practice to isolate the frog from the switch rails when powering the frog seperately (as in this case from the bridge rectifier).

 

 

 

 

 

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There are isolating breaks between red and blue shown by the orange lines. If you mean the red and black, then my earlier post applies:-

This will have to be done anyway and it is normal practice to isolate the frog from the switch rails when powering the frog seperately (as in this case from the bridge rectifier).

Yes I did mean black (eyes not what they used to be)

 

Sorry - that was not clear on the diagram. I would agree with the break in the switch rail under normal circumstances when the point is switched as normal and the switch rails are bonded to the stock by wire. But the whole exercise here is to remove completely any point operation. The points are completely static and the switch rail is soldered tight against the stock rail. I would worry that any further cutting of a gap in the switch rail before the frog would severely weaken the point to the falling apart stage or at least result in a twist of the switch rail, already weakened by filing a channel for the wheel flanges.

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I have a point like this on my 00 layout. It is normally used as a fixed trailing point, but will allow trains through reliably straight through, provided the back to back is accurate. I can't remember the wiring, but as mine is DCC, it involves a reversing module and a much shortned dead frog !

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I have not had a look at a 009 point in a while, but I suspect that they are similar to the H0 in that you should just have to remove some links under the point that link the frog to the wing rails if the breaks in the switch rails are not provided. I think that a slitting disc could be used to cut the rails without weakening the point too much if shorting of the wing rails against the backs of wheels is a problem - ideally the wing rails should be electrically connected to the frog or isolated.

 

The wiring for DCC is the same, except that the bridge rectifier needs to be replaced with an auto reverse module, and the stop section will not be required because there is no need to reverse the polarity.

 

 

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Dear RMWeb Team,

 

First up, hello from a new member smile.gif

 

Suzie, I stand corrected, and apologise. Having looked at your diagram after a good night's sleep, it does appear to achieve the same basic mission, while permitting the use of metal (electrofrog) points/turnouts. This is indeed a good thing for those who intend to use the technique with short-wheelbase locos, where pickup is often iffy at best.

 

However, in the "Devil's in the details" dept

 

1 - To make the Electrofrog version work requires a gap to be created/cut in between the frog, and the switchrails (where I've soldered the switchrails to the stockrails).

 

In most gauges under 16.5, using a regular razor saw or dremel to achieve such a cut is nearly impossible, without massacring the point.

(Tim from Fastracks in the US has been posting a "how-to" video series on Youtube, and the "cutting gaps" clip illustrates the problem brilliantly

 

 

Check around the 1min 30 sec mark...)

 

One _could_ use a precision jeweller's razor saw as shown by Tim, but this elevates the whole project IMHO from "any modeller with basic tools can do this, just grab a point/turnout, and have at it" into the realms of "needs specific tools, and precision skills", which is a tech-fail...

(It's just me, but I very much aim for

"any technique I demonstrate needs to err on the side of 'do-able by anyone, of any skill level, with _basic_ tools, anywhere, anytime...' "

 

Nothing stops the enthusiasm of a newcomer modeller to try a new modelling technique faster than the thought that,

"I can't do _insert inspiring technique HERE_ because i don't have _insert not-basic tool_ HERE_ ")

 

Indeed, one could argue that if a Fastracks-style toolkit is required, we may as well seriously consider handlaying the point from the outset... wink.gif

 

2 - With the frog now part of the "bridge rectifier fed" block, the option for _shortening_ the "entry end" of the bridge-rectifier-fed block,

(for the purpose of allowing the straight-route + part of the "loop" to be driven manually, as shown at the end of the PDF linked to earlier),

 

is no longer available. sad.gif

 

For pure "turning trains around" loops, this may be an acceptable compromise.

 

However, for those modellers who dislike the look of "obviously contrived balloon loop" track arrangements,

having the ability to treat even a short section of the "straight route" both mechanically and electrically as still part of the

"manual drive mainline" is a significantly important feature.

 

The key thing is "at what point of the loop is the train "captured" by the bridge rectifier,

such that it is not longer under direct directional control of the mainline throttle?"

 

With a Electrofrog point, this is just on the toe-end of the frog, and _cannot_ be adjusted.

 

With an Insulfrog, this position _can_ be adjusted,

and taken to the extreme,

need be no longer than 2 loco-lengths from the curved ("outbound") leg of the loop/point.

 

- 1 loco length fed by the bridge rectifier

- and 1 loco length fed by the single diode pair, to ensure the loco stops if the mainline polarity/throttle has not been set to recieve the returning train...

 

 

 

So, Suzie, I again apologise. The diagram as shown is a great solution for Electrofrog points,

and should make life easier for smaller footprint locos.

 

However, converting an Electrofrog point requires a little more "surgical" kitbashing,

(I'm pretty hamfisted, and I managed to make a Insulfrog version work... wink.gif ),

 

is not as flexible in terms of matching the gap-positions/block lengths to the layout operational/scenic requirements

 

and most modellers are fine with cutting gaps in "plain track" at the appropriate positions,

(It's just easier... wink.gif )

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

 

"...Rank Newcomer to RMweb,

hauling logs somewhere deep in the Aussie Bush..."

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Dear Kenton, Team,

 

Just sketched up a solution to Kenton's "single passing loop" theme,

you can look at a PDF version of it HERE

 

http://www.fairlightau.com/johnd/RMweb/Kenton_single_pass_solution.pdf

 

below is a poor res GIF versions

 

Kenton_single_pass_solution.gif

 

I have to say I don't like it myself, as it will require an _active_ cross-over train detection system

- magnets and hall-effect sensors

- LDR light detectors

- Infra-red "IRDOT" detectors,

- etc etc

 

to stop the current train when it hits it's "Stopping section",

and simultaneously change MainLine polarity to release the opposing train out onto the mainline...

 

There _should_ be a way to do it with _only_ a "dumb timer" reverser and diodes,

and I know I could (have done previously), if there were 2 (TWO) passing loops located around the circuit,

(see the "passing loop shuttle" schematic earlier in this thread, simply connect 2 such "passing loops" end-to-end in a circuit)

 

but with only a single passing loop,

and electrofrog points, this should work...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

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