Spring Pass - my first layout

[Graeme Dunbar]

Something that is worth checking carefully is the nature of their low force action. Some are 'low force' only because they have a longer lever arm so you are trading actuating force for distance moved and there may not be enough movement in the point blades to cause them to change state. It may be possible to 'pre-stress' the lever so it is just on the verge of toggling over but then a bump or some vibration might be enough to cause it to do so.

One way round this is to decouple the movement of the actuator (manual pushing of a lever or electro-mechanical) and the movement of the point blades, with the switch operating in sympathy with the lever, not the point blade.

This could be achieved by 'gearing' down the movement with an intermediate lever or employing a form of slip clutch or deliberate backlash. A common solution was to use the innards of a couple of segments of a chocolate block connector clamped at the appropriate place and distance apart to move a dropper wire beneath the baseboard, or an arm above the baseboard.

This is not quite it, but similar construction:
http://www.hall-royd-junction.co.uk/images/Point_02_800.jpg
(Not https, so you may have to click the link to see)
http://www.hall-royd-junction.co.uk/Hall_Royd_Model/layout_50.html

Edit: I've been naughty and cribbed the image and attached here (acknowledgement to the original source).

[Hugh Norwood]

One "tried and tested" method (but not used by me) to compensate for the difference in switch-throw to point-blade throw is the "Omega" link. Used, I believe, with those slide switches, it involves making a loop in the shape of a capital Omega with one end inserted in the switch "paddle" (?) and the other going to the link to the point. It's function is to take up any other-throw in the switch mechanism without stressing the points.

(Now I need to find a suitable photo...)

[Ian McAulay]

I've never really liked omega loops. They absorb extra throw but, because they are asymmetric, they tend to twist to one side as they do so. My preference is for a Z shaped section of wire which tends not to twist so much and is MUCH easier to make. I don't have a photo either, but I'll need to make some soon for one of the modules I'm building for the ScOONs modular project. I'll try to remember to take a photo and to post it in this thread. (It will be a while, so don't hold your breath.)

Ian

[The Sales Team]

One "tried and tested" method (but not used by me) to compensate for the difference in switch-throw to point-blade throw is the "Omega" link.

As it happens, some will be on sale online within the next week - SKU 952, if you were tempted (there is a picture, but you probably won't be able to see it until the item is back in stock). Plus assorted other GEM/Mercontrol point control items.

The Sales Team.

[Justin Phillips]

Thanks all for the info and advice. Will have a think over the coming days to work out what I will do next.

[Justin Phillips]

I have found some miniature micro-switches that have a very low required force and do just the job. It is held in place by a small blob of epoxy and cocktail sticks. Have fitted the first one and electrically it checks out, so just another 3 points to go.

I did make the noobie error of wiring the common wire to the underside of the frog where the small bonding wire is spot welded on. I almost melted the plastic around the frog, but have got away with it. Instead, I could (should) have added a dropper wire off one of the rails coming off the frog a little away from it. But you live and learn, and this layout is about learning.

[B.Meldon]

That is looking good.
From experience I would recommend that you ensure that you have access to the microswitch once the layout is complete, perhaps with a removable building or section of scenery.
Unfortunately you will find that it is the one switch that cannot be accessed that will be the one you need to get to at some time in the future!!
The same goes for the actual points, it is not a good idea to have a point in a tunnel where it cannot be accessed.

[Graeme Dunbar]

I used to have a photocopy of the multitude of variations on Murphy's Law. One was definitely on the inaccessibility of the part that proved to be the most likely to fail. :)

[Justin Phillips]

Agree, and I am placing the switches at the correct distance from each point to cover with a building or structure of some kind.

[Justin Phillips]

Track work finished with miniature microswitches, and all working as expected. Next job I think is to build the bridge.

[Justin Phillips]

Started on the bridge tonight. It is an I beam design, which will have braces to form a ladder. Done a dry fit of the abutments and the main beans, and I think the proportions look OK.

[B.Meldon]

Started on the bridge tonight. It is an I beam design, which will have braces to form a ladder. Done a dry fit of the abutments and the main beans, and I think the proportions look OK.

This looks good.
A bridge like this would have had check rails fitted.
As it happens the Peco 009 track is made so that if you add check rails with the same rail, on the sleepers inside the running rails they are fractional lower than the running rails so they do not catch on anything and you can still clean the running rails as normal.

[Justin Phillips]

This looks good.
A bridge like this would have had check rails fitted.
As it happens the Peco 009 track is made so that if you add check rails with the same rail, on the sleepers inside the running rails they are fractional lower than the running rails so they do not catch on anything and you can still clean the running rails as normal.

Thanks for the info. I wondered about check rails or just guard rails (wood?) fixed to the outer edge of the sleepers to stop the train falling off. I don't intend however on having a hand rail, so for someone to be able to walk over it (for maintenance), I was thinking of boarding down the middle.

[engerth399]

Boarding?? Luxury.  Many high viaducts in Cuba had only the sleepers to walk on,  they were not always well fixed, sometimes the odd one was missing.  Still if you want the picture you have to get to the right spot, even if you don't hasve a head for heights.

[Justin Phillips]

I am missing something on my abutments, and that is a small retaining wall / block to stop earth and ballast from falling. So I will probably model a small cast concrete block that will look like it is part of the concrete slab that is sat on top.