turnouts

[deadhead 49]

Thank you very much for the answer .Yours was the one I was looking for the most. You had the right idea from the start. bless you and thanks again

[jeffrey-wimberly]

 I believe I read somewhere that you can use a spring to hold the turnout in one position { straight}and the cars will take that route.The spring isn't strong enough to interfere when the cars are coming from the opposite direction{curve}. After the train finishes it's pass the turnout returns to the original position{straight}. My question: is this true and also what kind of spring do you use? thanks for your help

On my Bachmann remote operated turnouts I can set them so that a train headed south into the turnout will go from the main to the siding and it doesn't have to be reset for a train coming from the north. The train will simply push the points aside and continue on. When the last car has passed, the points will snap back to their original position to redirect another train into the siding.

[Dave-the-Train]

[Just in case anyone doesn't know already... Standard Railway/Railroad practice is that IN THE DIRECTION OF TRAVEL  a Facing Point/Switch is one at which you come to the blades first/the route diverges/you are faced with a choice of routes.  The other way round the points/switch are Trailing... you come to the frog first/the routes converge/you have no choice but to trail through the points/switch from one side or the other].

It seems to me that the big issue would not be the question of springing the blades reliably but wiring the switch for 2 rail operation.  I don't know whether DCC would be more difficult.  (I prefer to only use live frogs).

My Dad's 0 Gauge, stud contact, Finescale layout had one spring point way back about 1958.  That used a very small tension coil spring... the sort of thing you'd now find when pulling a dead printer apart... sorry, maybe I should be more specific... I mean a computer printing machine that no-longer works...

I don't recall ever seeing a sprung point/switch in H0 in 50 years... that might have been because it worked so well that no-one noticed it.

One problem with small springs that have to be finely tuned down to a load is that they can easily lose their elastic memory... i.e, become too weak.  Another is that they can get grit in them...

We also had some sprung points on the real railway when I was a kid and there may be just a few surviving... I don't know of any around where I work now.... although there is one still in place that has long been bolted up out of use.

If you can workout the electrics you don't have to have a spring.  All the spring is doing is holding the blades to a prefered side.  You can do this just as well... possibly more easily in a model... by attaching a weight to it via a crank or a cord round a pulley.  It would be a whole lot easier to adjust this... just file off the weight until it is light enough... or keep adding blobs of solder to increase weight (assuming that it is metal).  One issue would then be to make sure tht the bearing didn't bind and hold the blades in the wrong position.

I suspect that the spring in Peco points/switches may have been looked at a bit strangely above.  Peco use an "over-centre" arrangement with the solenoid operation kicking the points one side to the other.  Once kicked the power goes off and the spring built into the switch retains the position it has been tken to with the blade action and therefore also keeps the blades held in that position.  If you wanted a spring switch the thing to do with Peco points would be to take the over-centre spring out altogether in order to leave the blades free to be held or swung by the spring or flanges as required.  Leaving the spring in would render the spring and flanges useless for locating the blades.

Someone has rightly said that where some facing movements will go the opposite way to usual the RR provide a switch stand.  This can be done on the model.  The linkage between the stand and the tie bar driving the blades MUST have a lost motion device in a model and 99% of the time has one in the real thing.  It must have it in the model for the same reason you take out the Peco spring.

I don't know about the US but here some yard switches can be trailed through from either side without prior setting but have to be set to select the facing route.  These have a toggle drive in the mechanism - so that when you swing them the toggle makes contact and transmits the push but when the blades want to kick the mechanism as the first flange goes through them there is no resistance from the mechanism.  Somewhere I have pictures...  The toggle (if that is the right technical word for it) is a strecthed W shape pivoted at the upward point and contacting the rodding in the valleys... I don't know if any of the engineers we have can figure that out.

I'm wondering whether the "easy" route to go would be to use a treadle or track occupancy sequence to have a train approaching on the less favoured leg of the switch in the trailing direction trip a standard switch motor and drive the "sprung" switch to the required position.  I guess that rather than have to figure out when the switch could go back to its normal position the thing to do would be to detect approach the other way as well... ...

So...

What I am thinking here...

With a left hand turnout where the Facing direction of travel takes the right hand route and the trailing direction of travel comes in from the right hand leg (NB this is in the direction of travel) --- Then one way of sorting this out PLUS getting the same electrical 2 rail swithcing as everywhere else would be...

In each approach put two (three if you want) detectors (mechanical treadles, infra red detectors or whatever) set so that when they trip in the sequence for the appropriate direction of travel they will shift the switch blades if necessary.  If the blades are set right or the detected movement is in the opposite direction the system does nothing.  I'm pretty sure that this is straight forward if you know how to wire it.  (Anyone know the wiring?).

I suspect that there is a company here that has a system for this??? Kent Controls?  Or Keltron?  Something like that???  Kemtron?  Their system (that I saw waorking at Chatham Show about 2000/1 worked with Peco/over centre points... I don't know how it would get on with Tortoises needing a holding current.

One thing that would be possible with the travel detection would be to do the push-out-of-a-yard-track arrangement.  So long as there was enough lead between the standing end of a train and the switch (frog end for live frog) you could detect any train starting out of a track and not just the immediate switch but all the switches leading to the main could kick over to let it out.  On one hand this would also mean that the yard was left with a vacated track open.  On the other hand you could over ride the system to put an incoming train into a different track.  The exact pattern would depend on the arrangement of your ladder track.  (We had this on the ground at my first location back in 78).

Hope that this helps and gives some ideas.

[trainnut1250]

Deadhed 49,

 

Marklin (three rail AC, center stud) M track switches (semi tinplate) function exactly as you describe.  I happliy ran against the points throughout my childhood with nary a problem.  One of the hardest things for me to get used to in 2 rail was the fact that you would derail/short running against the points.  None of my 2 rail friends could understand why I wasn't paying more attention to this.  To them it was very basic.  To me it was basic the other way (although rare in US prototype). 

I might point out that Marklin HO three rail equipment is quite different than US 2-rail although it is the same scale.  Most of the differences that would matter in this case have to do with flange depth and width as well as the wiring of the switch.

I'll leave the matter of how well this works in two rail systems to those who have actual "hands on" experience in this area.  None of my switches on my current layout are designed to operate this way.  I haven't run against the points intentionally in years.

 

Guy

[tomikawaTT]

As I said in another post on a different topic, an ounce of hard data is worth 55 gallons of opinion.

Hard data:

• I make no claim to expertise.  All I can claim is well over four decades of tracklaying experience in 16.5mm and smaller gauges.
• I built my first prototype-style spring switch in 1963.  It worked as designed.  So have the many I have built since - including one put into service three weeks ago.
• By isolating the frog, a spring switch can be built that does NOT require any special circuitry more complex than wire leads to the running rails.  It can be made DCC friendly.
• The only way I have found to have a derailment on a properly installed spring switch is to reverse the train half way through a trailing-point move from the less-favored branch.  (Yes, I did make that mistake - once!  Only a slow learner will make it twice.)

Opinion:

• Spring switches either rely on built-in springs or on the springs of switch machines.  (The natural springiness of the rail is plenty.  No Peco switches, solenoid machines or piano wire necessary)
• Spring switches in smaller scales are unreliable/cause derailments.  (44 years of my personal experience indicates otherwise.)

To those who say spring switches can't/won't work, all I suggest is that you try one.  You might like it.

Chuck (modeling Central Japan in September, 1964 - with spring switches)

[deadhead 49]

I would like to thank all who replied to my question. Most of the best people are train people. They are there in a heart beat.I know that this was my frist question, but by no means it won't be my last. Bless alland keep them rolling   Steve 

[markpierce]

You are asking for a lot of trouble if you attempt to use spring turnouts in any of the popular scales.  Even if you solve the derailment issue, you'll need to avoid electrical shorts if you use two-rail power.  The point rails will need to be insulated from one another, and you would still need a switch to align the polarity for the route.  So, even if you have a successful solution, what have you accomplished operationally unless you are modeling an operational overhead-wire or third-rail electrical railroad?

Mark

[dinwitty]

piano wire from the hobby shop. But you might want to put a little more weight in the cars tho.

Light springiness...Atlas snap sswitches were like this all the time.

 

[Don Gibson]

 I believe I read somewhere that you can use a spring to hold the turnout in one position { straight}and the cars will take that route.The spring isn't strong enough to interfere when the cars are coming from the opposite direction{curve}. After the train finishes it's pass the turnout returns to the original position{straight}. My question: is this true and also what kind of spring do you use? thanks for your help

Chuck T:

METHINKS I was aswering the original post (above). Not yours

Methinks you missed the point.  Nobody said anything about weakening the springs of a two-coil machine, and the switch I described in my post is obviously NOT a Peco, or any other manufactured product.

I've never measured the 'spring tension' of the single-point spring switches I have in service.  I do know that I have no problem passing (trailing point) 4-wheel freight cars (1:80 scale, about HO bulk) that probably don't weigh as much as the NMRA thinks they should.  Or 8-wheel cars kitbashed from Athearn BB hoppers.  In the facing point direction they have proven absolutely reliable. ,,,One less place for Murphy to do his thing. - Chuck  (with spring switches)

I THINK if if one has the patience and skills to impliment ONE should go ahead - even if it's runng trains under water - however; I don't rescind  my comments or opinions about BASICS - even in the face of your (posted) expertese. Sorry.

[tomikawaTT]

Brother Gibson.

Say WHAT???

Methinks you missed the point.  Nobody said anything about weakening the springs of a two-coil machine, and the switch I described in my post is obviously NOT a Peco, or any other manufactured product.

I've never measured the 'spring tension' of the single-point spring switches I have in service.  I do know that they have no problem passing (trailing point) 4-wheel freight cars (1:80 scale, about HO bulk) that probably don't weigh as much as the NMRA thinks they should.  Or 8-wheel cars kitbashed from Athearn BB hoppers.  In the facing point direction they have proven absolutely reliable.

As a single operator building a large layout, I will happily adopt anything that eliminates a switch machine.  One less place for Murphy to do his thing.

Chuck (modeling Central Japan in September, 1964 - in HOj, with spring switches)

[Don Gibson]

SPRINGS are used with 'twin coil' switch machines to 1. hold the alignment over time 2.(Peco) insure good electrical contact since the Insul frogs also 'power route' past the frog. 3.Prevent derailments. 

Most springs are made stiff enough to do the above, and to 'soften' them  begs for trouble. Real railroads are heavy enough to force 'spring switches, where our models may not be.

YOU can play with springs, but when you reduce tension you lose reliability. Where is the point reached where 'enough' becomes 'too much' - or too little.

SECOND a heavier engine may force the switch, but how about the lighter cars? Are you planning to weight them to reduce the number of cars per train?

YOU could be opening a can of worms. ALL this to avoid throwing switch machines?

[tomikawaTT]

Spring switches are commonly used by prototype railroads in places where all the traffic approaching facing points will always take the same route.  For those rare occasions when a facing point movement will go against the spring, a standard switchstand is usually rigged to the points.  The switchstand target will have a big S on it, so drivers approaching from the trailing-point direction will know that they can pass through regardless.

Some of my semi-automated train movements depend on spring switches for their operation.  My 'spring' is simply a very long point rail, anchored securely at the frog end and free to move at the sharp end, held against the stock rail by its own springiness.  Flanges striking it from the frog end simply push it aside.  The opposite "point" is similar to the non-point casting used in single-point street railway turnouts.

There are also "pointless" turnouts, used in places where all movements are trailing point.  Both "points" are similar to the one on the un-pointed side of the spring switch described above.

Chuck (modeling Central Japan in September, 1964)

[wedudler]

That's true. The prototype does it, especially narrow gauge. Here in Germany at the Harz, the narrow gauge line (for tourists) has a loop for turning trains in this way.

Some layouts ago I used at my staging yard turnouts this way. But I used them one way only, from the frog side.

Wolfgang 

[deadhead 49]

 I believe I read somewhere that you can use a spring to hold the turnout in one position { straight}and the cars will take that route.The spring isn't strong enough to interfere when the cars are coming from the opposite direction{curve}. After the train finishes it's pass the turnout returns to the original position{straight}. My question: is this true and also what kind of spring do you use? thanks for your help