Single direction points

[Kenton]

Kato Unitrack #4 switches will do this out of the box - the frog can be set dead and the switch rails are sprung lightly enough that even Microtrains low-profile delrin wheels have no problem pushing them aside on exit. I've used them to make hands-off reversing loops in N-scale (DCC, so the reversing loop module takes care of the polarity and the train never stops)

 

Adrian

Hi Adrian. I have no idea what Kato track looks like, whether or not it connects easily to Peco OO9, or would suit this particular application and stock.

Just looking it up quickly on the web, I see it has a 19" radius curve - that is just far too big for this type of ng layout, (basically a pizza mine) and they do not look particularly cheap! There doesn't seem to be any description of them being anything other than normal insulfrog points - but maybe I'm just looking at the wrong site.

[Prof Klyzlr]

Dear Kenton,

 

You'll note in my examples, I literally only removed the throwbar,

there was no need to touch or remove any part of the sleepers or webbing.

This may explain why mine "stayed straight".

 

As a suggested plan of attack

 

- using a X-acto knife, lever up the little metal tabs which hold the spring retained to the toe-side "headblock sleeper"

(sorry for the mixed UK/US terminology! )

 

- remove the little keeper piece and the metal spring itself

 

- Now, I can't remember specifically how I did it, but IIRC the throwcar can be snipped into 3rds from underneath, using rail nippers,

(remove the "middle 3rd", which gives enough "flop around room" for the outside 3rds + associated switchrails to be removed and cleaned up easily. If the raised "pins' on each end of the throwbar get in the way, don't hesitate : just cut them off, we don't need them for this mission! )

 

OR you can use the hole thru the centre (which is there to match with the PCO twin solenoid point motor),

as a guide, drill thru it with a drill which is just smaller in diam than the width of the throwbar.

 

This will remove enough material to weaken the throwbar right in the middle, and it can be "snapped out" 1 half at a time, without damaging or removing any other part of the prefab sleeper structure...

 

 

As for the "soldering bit", it miht pay to re-check the PDF from Lynn Zelmer's "caneSig" site, linked to earlier. Unless Lynn culled it in the transfer from the original geocities text > a stationary PDF, (which is very possible),

I believe I mentioned using a pair of reverse-action tweezers to hold the switch and stockrails together while leaving both hands free for the soldering iron and solder roll.

 

As a cute by-product, the tweezers act as heatsinks, thus helping to avoid undue melting of the sleeper casting or under-rail webbing.

FWIW, I did both points on DCT using a basic 25W pencil solding iron, and regular 60/40 solder.

If he iron is noce and hot, you should be able to "get in and get out again" quickly, making a nice solder joint before the plastic really "feels the heat".

 

(That said, if your iron is not up to temp, or is struggling a bit,

the "dwell time" required to get enough heat into a code 100 or 80 rail to ensure a nice "not-cold" joint,

is going to give the sleepers enouh time to get hot and bothered...)

 

I really want this to work for you, just hope the advice helps!

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

 

 

OK I'm going to have another go at a new one this evening (I need 2 for the layout anyway)

I think I can remove the tiebar/switch assembly without cutting the webbing.

However when it comes to soldering they are going to be right at the solder hot spot - so the end result may just be the same.

 

I guess another option would be to do some selective sleeper replacement with pcb sleepers to lock up the geometry ... but the I guess I might as well be building hand-laid points and that defeats the simplicity and goes against my grain.

[Kenton]

Prof K thanks for keeping an interest in this.

 

OK about the despringing - something I do with any point any gauge.

 

But

- Now, I can't remember specifically how I did it, but IIRC the throwcar can be snipped into 3rds from underneath, using rail nippers,

(remove the "middle 3rd", which gives enough "flop around room" for the outside 3rds + associated switchrails to be removed and cleaned up easily. If the raised "pins' on each end of the throwbar get in the way, don't hesitate : just cut them off, we don't need them for this mission! )

 

OR you can use the hole thru the centre (which is there to match with the PCO twin solenoid point motor),

as a guide, drill thru it with a drill which is just smaller in diam than the width of the throwbar.

 

This will remove enough material to weaken the throwbar right in the middle, and it can be "snapped out" 1 half at a time, without damaging or removing any other part of the prefab sleeper structure...

 

Big problem here - the Peco 009 point is quite a different beast in terms of construction from most points. Note my discussion with Nick (Buffalo) above.

 

[i'll post some photos here later today when I get them out of the camera to explain the method used for the first one and the second attempt.]

Suffice to say that the tiebar arrangement is different and the switch rail hinge a bit of a naive arrangement.

 

As for the "soldering bit", it miht pay to re-check the PDF from Lynn Zelmer's "caneSig" site, linked to earlier. Unless Lynn culled it in the transfer from the original geocities text > a stationary PDF, (which is very possible),

I believe I mentioned using a pair of reverse-action tweezers to hold the switch and stockrails together while leaving both hands free for the soldering iron and solder roll.

 

As a cute by-product, the tweezers act as heatsinks, thus helping to avoid undue melting of the sleeper casting or under-rail webbing.

FWIW, I did both points on DCT using a basic 25W pencil solding iron, and regular 60/40 solder.

If he iron is noce and hot, you should be able to "get in and get out again" quickly, making a nice solder joint before the plastic really "feels the heat".

 

(That said, if your iron is not up to temp, or is struggling a bit,

the "dwell time" required to get enough heat into a code 100 or 80 rail to ensure a nice "not-cold" joint,

is going to give the sleepers enouh time to get hot and bothered...)

Don't take this the wrong way, especially as you have not been around this forum very long, but I'm probably nearly the last person to advise on soldering. Building kits for 40+ years these days on an almost daily basis in 4mm and 7mm, and very comfortable with a soldering iron

I used forceps in preference to tweezers (also hand free); also used resin core 60/40 also a trusty 25W iron.

 

Again as indicated by Nick above, these points seem to rely on the very thin plastic webbing (thinner than elsewhere) that is joining the large sleepers to retain structural integrity.

The webbing in this area wraps the side of the rail forming a "fishplate" exactly where the tail of the switch rails meet the stock rails. Just about any heat in this area will melt them.

[Prof Klyzlr]

Dear Kenton,

 

My sincere apologies, I recognize my 'newcomer' status here onlist,

and it was in no way my intention to appear as "the student lecturing the master"...

 

Looks like I may have made an assumption that because it 'worked so easily" using an N-gauge point in HOn30,

an actual "HOn30 point" would naturally follow suit...

(in theory at least, the geometry basis works for all gauges...)

 

That said, I stand by, and see the evidence which supports,

my initial assesment that you've obviously got the skills to make this technique work,

(what appears to be odd PECO design details notwithstanding... )

 

I just hope we can achieve a do-able result for your layout soon...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

[Adrian Wintle]

Hi Adrian. I have no idea what Kato track looks like, whether or not it connects easily to Peco OO9, or would suit this particular application and stock.

Just looking it up quickly on the web, I see it has a 19" radius curve - that is just far too big for this type of ng layout, (basically a pizza mine) and they do not look particularly cheap! There doesn't seem to be any description of them being anything other than normal insulfrog points - but maybe I'm just looking at the wrong site.

 

The main things about the Kato points are:

1. They have an integral roadbed

2. They have a built-in point motor in the roadbed (hence the cost)

3. They have settings to allow them to be power routing or not, and to have a live frog or not

4. They have Code 80 rail - North American modellers have used them with Atlas or Peco flex track by making sure the roadbed height matches

5. The sleeper spacing is similar to Peco Code 80 flex track

 

While they may not work in your situation, if one wants to have an automatic reversing loop (particularly a hidden one), they are a way of doing it without too much trouble.

 

Adrian

[Kenton]

Again as indicated by Nick above, these points seem to rely on the very thin plastic webbing (thinner than elsewhere) that is joining the large sleepers to retain structural integrity.

The webbing in this area wraps the side of the rail forming a "fishplate" exactly where the tail of the switch rails meet the stock rails. Just about any heat in this area will melt them.

 

First up a couple of images to illustrate the inconvenience of this structural webbing

 

 

The first taken side on shows the "fishplate" effect

The second taken from below, but note the curved switch is now re-inserted though not yet soldered up to the straight stock.

[Kenton]

OK lets go back to the beginng and illustrate the whole process (or at least attempt to)

I would have done this on the blog but I'm having problems with the blog area and anyway thought "keep it all in one place"

 

This modification cannot be done with the point in-situ

 

Step 1: Despringing

The next two photos show the OO9 point straight out of the box.

 

 

Using a knife or screwdriver, bend up the wings of the metal clip holding the spring plate in place.

 

 

Pull the clip out from behind, setting aside the keeper plate, the spring and clip.

 

[Kenton]

Step 2 - Switch rail removal and clean-up

 

The tie-bar carries an integral plastic block in which the switch rails are embedded. This block rides on the sleeper from which we have just removed the keeper plate and is held under the rail webbing. The keeper plate also holds the assembly forward on the point.

 

The switch rails on the Peco OO9 point are joined to the crossing rails by standard Peco metal rail joiners (SL-310).

 

Having removed the keeper plate as above we can now joggle the tie bar with the embedded switch rails back towards the heel of the point to release the assembly. You will notice that the joiners are not fully aligned and only about one-third of the joiner is on the crossing side.

 

 

 

Move the now unattached switch rail assembly towards the frog disengaging it from the sleeper.

The whole assembly can now be dropped out through the bottom of the point at the tie bar.

 

 

Remove the switch rails from the assembly using a sharp scalpel to cut through the tie bar handles close to the outside of the switch rails. They can then be removed from the center plastic block in which they are embedded. You will see that each rail has an inward facing tab.

 

 

Slide the metal joiners off the switch rails and make use of them elsewhere on the layout.

 

 

Cut away the metal tabs and file flat to the tail of the switch rails.

 

[Kenton]

Step 3 - The Rebuild

 

The rail will be tarnished maybe even coated in something from the manufacturing process and is known to be an issue when attempting to solder wires. So a glass fibre brush is used to clean up the inside of the stock rails and the outside surface of the switch blades.

 

Then using 60/40 multicore solder, as used for layout wiring, tin these rail faces. It is important to remember that a correctly tinned surface should only need to be a few molecules thick. It will be unavoidable to place more solder on these surfaces than required so the excess solder was removed with a fine file. The recess in the rail where the switch tails lie must not be filled with solder or the blade will lie proud.

 

 

Now take two standard Peco insulated rail joiners (SL-311) and trim half of one side on each.

 

 

Fit this half side to the crossing and then slide the corresponding switch rail into the other uncut side. We are doing this as the switch rails will be electrically bound to their stock rail by this modification and so the crossing has to be electrically isolated or a short will occur.

 

 

The sleepers are very susceptible to melting and in particular the webbing alongside the area about to be soldered is very thin. Any soldering needs wo be done with speed yet the rail does need to be heated sufficiently to melt the solder and form a good join. Just don't hang around.

 

 

Now clamp the tail of the switch rail against the stock rail ensuring that the rail tops are level. A pair of locking, sprung forceps is useful for this, however remember that the heat sink effect that they have, although protecting to some extent the plastic also cool the joint so be certain that your soldering iron is clean, well tinned and up to the task - a 25W Antex is fine. Applying heat to the joined flat bottoms of the rails is sufficient to make the join by melting the pre-tinned solder without getting solder on the rail face. Then flood the created 'V' of this join with more solder. Finally clean up the join with a file. Even acting fast you can still see that that thin strip of webbing has melted almost completely.

 

 

Now the curved switch rail is the most important of the two. It is eventually required to act as a check rail and must capture the passing wheel set within its channel prior to the gap that will be made in the straight switch rail. Simply soldering the curved switch in the same way results in a gauge of 9.2mm at this location and although most OO9 wheel sets will tolerate this, by moving the rail inwards by a fraction allows the formation of a neater channel and moves the point of capture nearer the heel of the point. Imparting a small kink in the tail of this switch makes this offset. Though care was taken not to make the returning inside gauge less than 8.8mm

 

[buffalo]

Looks promising so far, Kenton. Do I detect a certain sleight of hand here? In the third photo of step one you appear to have already removed that nasty little piece of webbing that bridges over the tiebar. This is what I would expect if you are going to remove the switch blades complete with the tiebar. In my experience, there's no room to do it any other way. However, in step 3, you seem to have reinstated it just in time to melt it with the iron Did you discover that it was possible to cut out the tiebar before removing the switch rails? It occurred to me that this might be possible, though I haven't tried it.

 

Looking forward to step 4

 

Nick

 

ps. btw. my understanding is that the heel is where the switch blades are hinged (or clamped with a chair in a flexible switch) and the toe is the pointy end near the tiebar.

[Prof Klyzlr]

Dear Kenton, Nick,

 

The N gauge points used on DCT did not need the "bridging piece" to be removed to remove the throwbar,

although it's been a long time since I did DCT's conversions, so I may need to recheck...

 

 

Yep, just below the purple dotted line, it's still there...

 

I know they _did_ have the metal tabs on the switchrails, where the switchrails joined into the throwbar. IIRC, a few seconds work with some sidecutters (_not_ the Zuron rail nippers), removed them cleanly...

 

And I totally agree, this is the kind of mod which definitely needs to be performed and checked on the workbench,

(it's a odd-yet-satisfying feeling to flick a car thru each route of such a point on the workbench,

and marvel at the head-twisting simplicity of the "that'll never work" solution ),

 

_not_ retrofitted to an already-in-situ laid point,

(Although, with some tweaking, I'm pretty sure it could still be done in-situ if One was really committed...)

 

Kenton, your step-by-step is a lot more precise than my initial efforts,

both in terms of the actual doing, and the documenting of such.

I love it!

 

Can't wait to read the next installment...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

[Kenton]

Looks promising so far, Kenton. Do I detect a certain sleight of hand here? In the third photo of step one you appear to have already removed that nasty little piece of webbing that bridges over the tiebar. This is what I would expect if you are going to remove the switch blades complete with the tiebar. In my experience, there's no room to do it any other way. However, in step 3, you seem to have reinstated it just in time to melt it with the iron Did you discover that it was possible to cut out the tiebar before removing the switch rails? It occurred to me that this might be possible, though I haven't tried it.

 

Looking forward to step 4

 

Nick

 

ps. btw. my understanding is that the heel is where the switch blades are hinged (or clamped with a chair in a flexible switch) and the toe is the pointy end near the tiebar.

 

Ah well spotted - that photo was of attempt No 1 - the one that didn't work.

As you may have gathered from the notes it is NOT necessary to cut this webbing before removing the tie bar assembly (because it melts later anyway )

Neither is it necessary to cut the tie bar assembly BEFORE removing it from the point. Just joggle the assembly to free the rail joiners then forward to free from the sleeper and it simply drops out. The tie bar is not trapped by the webbing.

Then, once you have removed the complete assembly, is the time to chop off the tie bar arms so that the tab can be removed from the slots in the lump of plastic that remains.

 

 

On the subject of heels and toes. I have always understood that the comparison of a point is with a foot. As with a foot going forward a foot has one heel at the back and more than one toe at the front. So a point is normally approached from the single track end and a train normally passes through to one of the selected routes (toes) on the other end. In the reverse direction there is no route choice it is simply either a continuation of a curve or a straight track with the mechanism of the switch rails preventing derailment. That mechanism does not have to be selective as the switch could be simply sprung.

[buffalo]

...

Neither is it necessary to cut the tie bar assembly BEFORE removing it from the point. Just joggle the assembly to free the rail joiners then forward to free from the sleeper and it simply drops out...

Interesting, I'll have to try that again sometime. When I first tried converting one of these to an insulated hinge, I couldn't get the blades out this way as the metal rail joiners seemed too long to be able to free the hinged end of the blades, and I didn't want to destroy the metal joiners in case I needed to restore the turnout to it's original form. Since then, I've just assumed it was impossible. Obviously, more fiddling is needed so I'll try this on the next one.

 

On the subject of heels and toes. I have always understood that the comparison of a point is with a foot. As with a foot going forward a foot has one heel at the back and more than one toe at the front...

Yes, I used to think that, but wondered why I couldn't make sense of much of what I read about turnouts Then I read David Smith's 'GWR Switch and Crossing Practice' which includes several diagrams where the toe and heel are labelled as I described above. Continuing the foot analogy, I now think of it as placing your weight on your heel and swivelling your toes from side to side. Though whether that is the origin of this, admittedly strange, terminology, I have no idea

 

Nick

 

Edit: referring again to that volume, I notice that the thing we have been calling a 'tiebar' or 'tie bar' should be called a 'stretcher bar', at least in GWR S&C speak.

[Kenton]

Interesting, I'll have to try that again sometime. When I first tried converting one of these to an insulated hinge, I couldn't get the blades out this way as the metal rail joiners seemed too long to be able to free the hinged end of the blades, and I didn't want to destroy the metal joiners in case I needed to restore the turnout to it's original form. Since then, I've just assumed it was impossible. Obviously, more fiddling is needed so I'll try this on the next one.

The spring and keeper plate do need to be removed.

As you see in the photo the metal rail joiners are scewed with very little gripping the crossing - obviously these need to be detached from the crossing end first. Hence the joggling.

Without the removal of the spring+keepr plate you would not be able to slide the tie bar back far enough over the sleeper to get the joiner free.

 

However in theory it should be possible just to slide the rail joiner back even further on the switch rails as there are no chairs in the way.

[Kenton]

Step 4 - The First Cut

 

First the tool used - razor saw

Second tool - patience

Third tool - a steady hand

 

 

As you have seen above by my first attempt, steer clear of the dremel disc cutter. It is just too violent and uncontrollable.

 

Use the stock rail as a guide, but beware the saw will tend to pull towards the curved switch rail - that very slight stock rail curvature again. Once an impression has been made in the soft solder in the V you can use the plastic check rail further down the stock rail as a saw guide. But be careful not to hack through it.

 

 

I also discovered that cutting from the "heel" end you were soon cutting the fishplates as retaining a perfectly level cutting plane on the saw is very difficult.

Running the saw from the other end seemed to help, but only once the cut had been established.

 

 

Eventually, the cut is deep enough to take a wheel flange.

The channel was then tested using a chassis. The Kato tram chassis manually sailed through in both directions without a rumble, but the Bemo truck again tripped on the V

As we have established before this is easily fixed with a couple of draws of a file down the channel. Though I suspect this issue has more to do with the Bemo's gross wheel set back-to-back and flange dimensions.

 

 

A slight brush with a rat tail file was required to clean the cut edge on the curved switch rail.

 

As the cut actually parted the stock and switch rails at the soldered V though not the underside at the switch tail - think a mode generous and deeper blob of solder here would be advantageous on the next one.

[Andy C]

Kenton

 

It was me!! Check out myNew Hey thread on the old site - we altered all the outlet poits from the fiddleyards to get away for the need to switch them. They work really well!

 

http://www.rmweb.co.uk/forum/viewtopic.php?f=9&t=5181&start=350

 

Now found it, its on page 15, credit to Mike Turner on for the ides.

[Kenton]

It was me!! Check out myNew Hey thread on the old site - we altered all the outlet poits from the fiddleyards to get away for the need to switch them. They work really well!

 

http://www.rmweb.co.uk/forum/viewtopic.php?f=9&t=5181&start=350

 

Now found it, its on page 15, credit to Mike Turner on for the ides.

I see. But that is very much a hand built solution and in a much larger gauge. Though must admit that the check rail solution given by Mike Turner really does look elegant.

[Prof Klyzlr]

Step 4 - The First Cut

 

First the tool used - razor saw

Second tool - patience

Third tool - a steady hand

 

As you have seen above by my first attempt, steer clear of the dremel disc cutter. It is just too violent and uncontrollable.

 

SNIP

 

As the cut actually parted the stock and switch rails at the soldered V though not the underside at the switch tail - think a mode generous and deeper blob of solder here would be advantageous on the next one.

 

 

Dear Kenton,

 

Glad to see it's all coming together for you,

(touches of Hannibal from "the A-Team" )

 

Can't help but chuckle that some previous words in this thread,

("...the faster the tools works, the more certain you have to be that the bit you're about to cut is the right bit!...")

 

and the "pooled solder around the stock/switchrail joint" technique,

 

appear to work just as well in the northern hemisphere...

 

You're more than 1/2 way there, looking forward to seeing the results...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

 

PS On one of my previous HOn30 Aussie logging layouts,

 

http://www.zelmeroz.com/album_model/members/klyzlr/BroughtonVale.pdf

 

I played host to mostly MicroTrains wheelsets and LifeLike N-scale SW1200 mechs (kitbashed into HOn30 Class A Climaxes). However, the log bogies (disconnects) were built on MT archbar trucks equipped with Atlas metal wheelsets,

 

http://www.hon30.org/disconnects/discon.html

 

which were wide-of-tread and had a under-dimension B2B. This caused some challenges thru PECO N gauge points, but after some fine tweaking, the entire roster of log bogies could be run at speed (50+smph), in either direction, empty, either pushed or pulled, without fear...

 

 

I have since run these cars on DCT, and they played fair thru the "one-way" points without any modification to wheelsets or pointwork...

[Prof Klyzlr]

Kenton

 

It was me!! Check out myNew Hey thread on the old site - we altered all the outlet poits from the fiddleyards to get away for the need to switch them. They work really well!

 

http://www.rmweb.co....=5181&start=350

 

Now found it, its on page 15, credit to Mike Turner on for the ides.

 

 

Dear Andy,

 

Love the solution, but for those who shy away from handlaying, particularly fine precision flangeways and guardrails,

being able to mod a cheap commercial point into a bulletproof "one-way" point is just another solution,

and may be just what the doctor ordered...

 

I know I built my first PECO-based "one way point" after seeing a friend's dual-gauge HOn3/HO multi-loop-with-auto-passing-siding show layout, featuring handlaid "one-way-points", and thinking,

 

"I could never do that from scratch,

if only there was a way to start with something 'working' and kitbash it to get a suitable result..."

 

Just another example of how there's always at least 3 different ways to peel a feline when it comes to Model Rwy "problems"...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

[Kenton]

Step 4 - The Final Cut - in theory

 

This time use the outside of the plastic check rail further down the stock rail as a saw guide and cut into the soft solder V approximately 15mm along from the tail of the switch rail.

 

The important thing about this cut is that it must be far enough back along the the point so that the newly created channel on the other side can capture the wheel set, yet not so far as to overly narrow the gauge at the gap.

 

 

The end result, in theory should be a complete point where the only direction through is straight ahead from the heel end yet trains pass uninterupted from either toe end.

 

 

Unfortunately, testing this has been problematic.

With the Kato tram chassis the results are quite good at speed but there is a definite snag returning on the curved side. The Bemo truck falls off almost every time.

 

I am pretty certain that the problem lies in the narrow channel on the curve side rather than the slight narrowing of the gauge.

A search round the WB has failed to come up with a solution to remedy the problem. I refuse to revert to the dremel.

 

I will shortly be starting on the third attempt - I need 2 (I think the first one is unsalvageable) so if there any requests for more photos now is the time.

[Prof Klyzlr]

Step 4 - The Final Cut - in theory

 

This time use the outside of the plastic check rail further down the stock rail as a saw guide and cut into the soft solder V approximately 15mm along from the tail of the switch rail.

 

Th important thing about this cut is that it must be far enough back along the the point so that the newly created channel on the other side can capture the wheel set, yet not so far as to overly narrow the gauge at the gap.

 

 

The end result, in theory should be a complete point where the only direction through is straight ahead from the heel end yet trains pass uninterupted from either toe end.

 

 

Unfortunately, testing this has been problematic.

With the Kato tram chassis the results are quite good at speed but there is a definite snag returning on the curved side. The Bemo truck falls off almost every time.

 

SNIP

 

Dear Kenton,

 

Define "Bump"?

 

1 - A nudge sideways as the curved-stockrail side wheels encounter that remaining lump of switchrail towards the throwbar end

(the exit/curved route flangeway doesn't follow the curved stockrail railhead inner face).

 

2 - A nudge sideways as the exiting wheelsets get clear of the Straight-route flangeway and remaining "seperated head" switchrail,

and 'pop' accross such that the flange re-joins the OEM straight stockrail inner face

 

3 - a "hump" up-and-over as the curved stockrail side wheel flanges ride over the soldered switchrail

(make flangeway deeper?)

 

4 - a _kinda_ "hump" up-and-over as the closing area between the curved stockrail and the associated switchrail tightly constricts the wheelset position

(carve away the backside of the switchrail with a small file, such that the closing flangeway forms a "funnel shape"?)

 

 

Notice the bits in RED. The flangeways forms a definite "funnel" gathering shape, whereas your last pics seem to show a situation where the flangeway "tightens" to a very specific "choke point",

then "flares open" again, to get past that lump of remaining switchrail...

 

 

Note also the inner face of the curved stockrail has been filed, possibly to give more "slop" as the wheelsets "gather" in the funnel-end of the flangeway...

I assure you this was all "trial and error" filing/trimming, but the patience/time taken repays in subsequent smooth/reliable operation...

 

Happy Modelling,

Aim to Improve,

Prof Klyzlr

 

PS: I'm sure I had some BEMO skips or similar lying around nearby,

if I can dig them up, I'll run them on DCT for comparison purposes...

[Kenton]

Prof K

 

First a caveat on the testing so far - it is not under powered movement but simply push-shove and let roll basis.

 

Although there is some of 1 and 2 - the final release of 2 does not at this point appear to be an issue.

 

3 is definitely not an issue the cuts are level with the original flanges on the rails and the plastic chairs. Cutting either channel any deeper will re separate the rails.

 

 

4 - a _kinda_ "hump" up-and-over as the closing area between the curved stockrail and the associated switchrail tightly constricts the wheelset position

(carve away the backside of the switchrail with a small file, such that the closing flangeway forms a "funnel shape"?)

 

As indicated above the channel is not wide enough

 

 

The red circle showing the main problem area rather than the narrowing of the gauge across the yellow line, though the latter is not ideal some remedy to that might be made by more filing back of the remnant of the switch tail though on the unaltered point there is considerable thinning of the stock rail at this position. The resultant filling of this thinning by the switch tail doesn't really create much of a hump, it just looks that way in the photo.

 

 

Perhaps the next photo illustrates the problem better. I could not get the Kato chassis to do this as there is more weight in that along with the wheel flange being thinner. The Kato chassis does get gripped at the same place but it seems fickle. As you can see the Bemo truck is well and truly stuck here and with the application of more momentum it simply rides up and then it is just chance if it gets through or drops off the rails - the later gauge narrowing and flick past the straight channel probably not helping.

 

 

I want to widen this channel but I simply do not have a thin enough file in the tool box - (and I do have many in there) in fact I don't think I have ever seen a file that thin. The saw blade was too thin. The channel is even thinner than the cutting disc wheel -- which explains why this area was not a problem on attempt No1.

 

Again, thanks for the continuing interest - I've not given up yet and will be starting the next one shortly.

[Kenton]

Just been doing some measurements: (all ±0.01mm)

Razor saw blade 0.40mm

Cutting disc 0.59

 

Channel between curved stock and switch 0.47

Channel between straight stock and switch 0.58

(but there may have been some forced movement of the switch in both cases)

I think the extra width of the straight is in part due to the curvature of the stock resulting in the razor saw cutting at an angle.

 

Kato chassis flanges 0.46 : 0.45 : 0.45 : 0.44

Bemo truck flanges 0.51 : 0.53 : 0.50 : 0.54

 

Clearly the channel needs to be an absolute minimum of 0.55mm probably more likely 0.60 or 0.65mm