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Point Motors

15614 Views 53 Replies 14 Participants Last post by  steamrailuk
N Scale:
Point motors are my frightener and always have been. They are big, noisy and power hungry, but most they are expensive. Not when buying one or two but when buying 30-40 or more and one doesn't even get to see them, under the board. If you want something simpler and neater on top the price doubles. There rarely seems to be more than a penny or two discount for quantity.

This is probably a stupid post but I have wracked my brain trying to find an alternative. I cannot believe that nobody has found an answer to one point one solenoid.
It is easy for one switch to operate many, but not the other way round. It spoils the cost estimate prepared for the wife, when one forgets to factor the solenoids in...

Has anybody come up with anything at all, other than finger pressure.

Yes; I know I am leaving myself open here.
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Alternatives to solenoids include, in no particular order and without regard to expense:-

Motor driven such as Tortoise, Fulgurex and Conrad
Stepper motors
Memory wire - a bit of a stretch even for N?

You should be able to rig up an appropriate linkage for a pair of n gauge points which motorised points have the power to drive. The difficult part may revolve around the distance of travel.

I use Kato points with the motor built into the ballast.
Hi Don

I think...not too sure that I read somewhere about 'memory wire' AKA muscle wire or Flexinol being used to control points.
I have no idea if you could get it to work or it would be reliable enough to to use with an accessory decoder for eventual PC control.

Having just checked the Merg kit locker they do have a memory wire starter kit enough to control 4 turnouts, this maybe something you might like to try.
You would need some crank arms as well as springs to pull the memory wire back to it's original length.
In the technical notes it does say another member has used only 30mm of memory wire to operate N-gauge points, this could be powered by an accessory decoder which you can alter the pulse length on.

It may work out more expensive than point motors, but I guess if you buy a decent length of wire it could work out cheaper.

The slow acting motors are all much more expensive so I don't think we need go there!

The only other alternative is using WIT items (wire in tube) which is exactly what it says, but you wouldn't be able to operate these using a decoder and hence PC control.

I've not seen anything else (which doesn't really mean a great deal) but you may end up having to scratch build something for yourself.

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If I hadn't already gone and bought loads of solenoids I'd probably be considering servos. Similar price to solenoids and you need to make your own mechanical linkage and driver circuits but look like they achieve smooth quiet operation at much less cost and size than the Tortoise and similar. Yet again MERG do a driver kit...
Well I must say I didn't actually expect anything.
Thanks all for the input, I have not come across Kato, I'll look.
Memory wire I have come across in other fields but would not have thought of its use here, worth a look I think, even just for interest.

What I probably meant was a means of doing the opposite of one switch to several points. Some clever device that has one motor to several points. i.e. perhaps a multi stage movement??? multi direction movement. Perhaps the equivalent of hooking different points to a common motor but automatically.
In fact I'm not sure what I mean or I would have done it.
I'll leave it at... 'the opposite of one switch to several points. Some clever device that has one motor to several points.'
It seems stupid, but don't all inventions at first; so I was hoping someone may have cracked it.
I would like to pay £1 per point operated.
Is this ridiculous?
Just as an example, the Peco scissors crossover needs 4 point motors, it's wiring is complicated and the RRP is £49.00. The Kato scissors crossover on the other hand has built in point motors and uses only 2 wires to control everything with an RRP of £41.99. MG. Sharp are one UK stockist of Kato Unitrack.
poliss, I found an example of that crossover just now. Yes a slight saving. This is an example of what I meant... the crossover only has two possible positions not four (am I missing something), therefore there should only be a need for two motors (nay, dare I say one) and the rest should be done mechanically.
Correct me, that I have got the purpose of the scissors wrong.
QUOTE a means of doing the opposite of one switch to several points. Some clever device that has one motor to several points. i.e. perhaps a multi stage movement??? multi direction movement. Perhaps the equivalent of hooking different points to a common motor but automatically.

My thought would be to create a mechanical linkage with cranks / rods or whatever to join the two points together and then drive that with a single motor. I wouldn't be surprised if "wire in tube" people do it all the time, so searching for that method of operation might yield better results.

£1 a point? Short of buying some solenoid devices as a job lot, I think you may be a bit optismistic. Of course there's always eBay and if you keep your eyes skimmed you might find someone disposing of their old Peco motors because they were "upgrading".

Thanks dwb, I like one motor and wire in tube, especially if they are close. I will certainly search on that technique and see what happens. With lots of points that always change as pairs this could reduce the price from £3.50 each point to £3.50 per pair. Not Bad.
If your looking for value for money Kato are the way to go vs the cost of a point from peco for example (8.00) then whichever method you choose to operate them in your last post wire and tube at £3.50 and the time crawling under the board to set it up.
With Kato 14.99 wired ready to go and no crawling under the boards cheaper if you go to ebay on plaza Japans site.
This is the Modratec W.I.T. components:-

Modratec WIT

There is a UK supplier of WIT items as well GEM model railways they call it Mercontrol:-

GEM Mercontrol

You should be able to find all the linkages you need from that lot.
I've not priced it up, so I have no idea if will be cheaper or not, it may depend on how much you order.

Anyway hope it helps.

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There would only be one loco going over the scissors crossover at a time, so it would either be set as straight, or cross. The built in point motors do that for you. The price examples I gave were the full prices from two of the major UK retailers. I mostly by mine from Plaza Japan like Nick, where they are much cheaper, when they are in stock. There's now a UK based Ebay shop ( fastrack99) that sells the Kato Scissors Crossing for £38.65.
@upnick: Thanks but money is hard earned and I have time to crawl under the boards.

Thanks for those interesting links wiggy25, I shall definitely evaluate that.

My 'point' poliss was that with peco it should have been possible with one motor and mechanics, not four.
QUOTE The Kato scissors crossover on the other hand has built in point motors
being plural I presumed that there was also more than one motor on kato but one switch required; hence they had reduced the wiring only and of course included the motors.

My problem with Kato is a box full of peco points!! as yet without motors.

I am not sure but thought I had also read that mixing the two resulted in a height discrepancy problem. Be that as it may, Kato will not help at this stage.
Do not think me ungrateful, but money is an issue.
Having just looked; thank you again; Gem seems expensive but Mercontrol would seem to work out at about £1 per foot for tube and wire as long as you don't turn corners, and don't use copper tube, but ptfe.
That is worth looking at if the pair of points are close.

Once you start adding bellcranks (and whistles) etc. then it might become marginal and not worth it.

[Edit] I also just noticed on the Modratec site this link for anybody who is not sure about signalling practice in various countries
change doc number for others
QUOTE (Donone @ 4 Oct 2008, 07:47) <{POST_SNAPBACK}>[Edit] I also just noticed on the Modratec site this link for anybody who is not sure about signalling practice in various countries

The Modratec is a brief summary of British practice. run by John Hinson gives much more detail on British practice including the types of signal used by different companies pre and post the 1922 grouping and after nationalisation.

And we have our own Signalling sub-forum under this 'Tracks, Layouts & Scenery' heading.

John Webb
Right, thanks for that.
QUOTE (Donone @ 4 Oct 2008, 14:19) <{POST_SNAPBACK}>My 'point' poliss was that with peco it should have been possible with one motor and mechanics, not four.

***Peco point motors are incredibly inefficient (they draw approximately 4 amps at the time of throw) and unless they are close to perectly aligned when installed on the point, have difficulty throwing one point, let alone 4. There is no way you can reliably control several with one PM unless you modify the points.

To be honest why you'd want to mve multiple points except in a crossover or scissors I have no idea, as its neither good for operational flexibility or prototypical, however, I do appreciate the need to save cost where possible.

But - you cant do it with Pecco points as they are... If you want to move multiple points with one motor, then you will have to modify the points to remove the latching spring.... and use a latching type motor as per seeps offering OR go to motor drive.

The lowest possible cost method is in fact a series of cranks, linked to a return spring and pulled "off" using a simple lever and string or similar + pulleys. This method will work but it requires good mechanical expertise and realtively high maintenance.

You say you are a hands on person and OK with electronics/electrics, so here is a possibility: It is cheap enough for one per point even on the lowest budget if you are OK at scrounging bits & bobs here and there....

(1) remove the spring from the peco point and use the softest possible return spring to hold the blades at their most commonly needed rest position/route position.

(2) wind your own electromagnetic single solenoid coils from fine winding wire, with an impedance high enough that it will not overheat if latched "on" for an extended period. I'd suggest the static impedance of the coil should be more than 150 ohms to be safe - thats a lot of turns of wire so use a drill to wind it. (better to connect a DC conctoller to a battery drill so you can slow it down enough so that you can guide and lay the wire very evenly on the bobbin)

(3) Use a bit of steel rod or part of a 4" nail for a slug and a bobbin made up from a length of plastic tube & end caps.

(3) link this to the other end of the points throw bar

You can then use a simple SPST switch for control.

final option:

look at old floppy disc or CD drives and similar geared motor drives.... they are easily adapted if you are good with your hands nad understand the fundamentals of electronic control.

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G'day Donone !
No cobber , not a stupid question at all,bonzer post.{ . . . . and now a bonzer thread }
I've been looking for any form of acuation for Z spur points and it seems like you say , it's a bit of a frightner !
Good question where you ask about one point one accuator , I'd never thought of looking outside the "box"
in relation to that problem.
To bring the cost down...that's the one.
I can't think of any way of cascading control from one mechanical device to multipule accuations.
Wire in the tube is one I just dicovered, here , the other day. Mercontrol/Modratec are my flavors of the day at the moment.
I'd only discovered Fulgerex as well the other day[ beaut pice of engineering. Love it.], and there is tortise.These are good products, when you have to acuate points , for me the piggy bank is soon empty.There is also the issue of placement and service/maintenance. No matter how good something is ; at some stage it will need adjustment / repair / maintenance. Question. How will you get too what you have just built, too perform needed work ?
Z spur/OO , you have to have something to move the rails. Lots of possibilitys but it's fair dinkum that you have to have a quid left to buy something to run over the points.
I'm still searching around ; but with Z spur the possibility exists that memory wire might do the job in one go. COOL!

One day I want something to acuate points in HO, so , at the moment what works for me is wire in the tube.
I haven't used wire in the tube but at the Brisbane Model Train Show , Modratec are there and in 2009 I'll certainly be picking their brains.
WIT seems to give an ease of placement to bringing accuation to the throw bar, there are other methods all ready given as examples, Donone; in this thread that work well.WIT is my opinion of the day!
It seems to me that if there is any hope of bringing one accuation device { electrical/ mechanical/ pneumatic } to switch points, what is used to accuate the throw plate must be bought to a central area. If one was too then to use push to accuate, the terminus of the the accuation device would then need(?) ie., using wire , a tiny round plate to act as the target.
The accuator must then be motorised to allow movement to the the target, must accuratley hit the target, and move on to the next target.You would have too have something then to monitor the moveable accuator!
Food for thought, but all this typeing has made me thirsty, so I'm off to sink a tube.

Any thoughts any one?

Hope my ramblings were of some use Donone.

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Thanks to both Richard and Rowan.
QUOTE Hope my ramblings were of some use Donone.
Ramblings, if that is what they are, are good from everybody in this 'think tank', how else to move forward and innovate.
If there is any loss of movement in WIT it can easily be made up or multiplied with a bell-crank, so distance, slack and quantity should not be a problem. Since the 'motor' is no longer restricted to the standard point motor, strength can be increased. Thanks for the input Rowan.

@Richard: thanks for the input, valuable as is every comment. Operating two points at the same time and always the same pair would not seem to be unusual in a situation of a passing loop. Why only change the entry end and later the exit end, why not both together even though when you exit you are not actually entering as well. So the other point is not actually traversed by the train every time, no train is likely to be close enough to the other end of the loop to be passing and requiring the point the other way. I am not saying, every position, but there are some where you may as well change them together (no harm done!).
Winding my own transformers is a thing I vowed I would never do again, so I guess this will apply to solenoids also.

In general, though maybe stupid, (due to lack of specific knowledge on railway setup, that's why I am here), in electronics 4 wires can become 15 conditions by binary coding. Using a decoder 16 possibilities become available. The opposite is true in that 15 wires in can become 4 by encoding back to binary (or BCD). The above excludes zero.
I am looking for the same mechanical answer though maybe not quite 4/16. Why not one actuator to do the final job, and another two (four combinations) or three (seven usable combinations) to select which links are actually moved. This does not restrict itself to moving the same points always together! By 'selecting' which points to change as binary or easier, BCD, there would be no restriction and a whole route could be done, with thought.

If anybody is going to suggest that binary coding cannot be used in mechanics, then look at the 'Teletype' If you remember the old fashioned football scores on Saturday evening. The keyboard is entirely mechanical and by operation of some, say 60, keys, 8 bars encode this at right angles into binary movement, i.e. which combination of the eight bars move. This is done with cutouts in the top of the slider bars.
No that won't work here but, something a little simpler and smaller and more limited??
A mechanical decoder.
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