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Using Tortoise Switch Machine to Power Hidden Staging Yard

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Using Tortoise Switch Machine to Power Hidden Staging Yard
Posted by trafficdesign on Thursday, December 3, 2015 7:53 AM

I am building a 10 track hidden staging yard and would like to have only the active track powered when calling up a locomotive. There will be 10 stub-ended storage tracks.

Reason is that I will be storing 10 - 20 sound equipped locos in staging and do not want them to draw track power until I call them up for duty.

The layout is DCC powered by a digitrax Zephyr Extra and uses Atlas Code 100 track and Atlas Customline Mark IV #6 and #8 turnouts. All turnouts will be powered by Tortoise Switch Machines.

Can I use the contacts on the Tortoise to route power to the yard tracks only when the points are thrown off the main? I am a newbie and a bit 'electrically challenged' so any pics or diagrams are REALLY appreciated.

Appreciate any thoughts,

Bernard

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Posted by mlehman on Thursday, December 3, 2015 8:39 AM

Up to the limit of the contacts on the Tortoise. If you're talking just the single yard track of one of the two tracks served, probably so, assuming there will only be 3 to 6 sound units on each track. 10 to 20 would be too many I'm pretty sure, but they'll be scattered on several tracks I presume.

The Tortoise has two sets of contacts. You only need one set. you feed + and - power to the inputs on one contact. Then you run a "green" wire (doesn't need to be green but green = frog power works for me) to the frog. When the thing is thrown it feeds power to the designated track, while the other track gets two rails that are each the same polarity, so nothing moves on it.

If the yard is all single ended tracks, then you're good. No gaps needed, as power will feed down the rails and not encounter opposite polarity.

If double ended, you have to account for what will happened when the other end is thrown also. You'll need gaps after the frog, so you'll need to also run the green wire past those gaps to feed the rails there.

If DC, then wire the two Tortoises at either end to the same control switch so they move together and power to the rails is coordinated and you avoid shorting things if one was thrown and the other not.

With DCC, you can get a remote module (I use NCE Switch-Its or the Switch 8, for staging), then program macros so that each one chooses the correct yard track assigned to it by throwing ALL the turnouts  leading to that track at BOTH ends at the same time.

Mike Lehman

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Posted by BroadwayLion on Thursday, December 3, 2015 10:12 AM

Yes you can. But you need to control it at the last switch into the yard as well as on the first switch.

The first switch will apply power to the yard throat, but if you do not also use gaps at the individual switches they will all power up when you apply power to the throat.

It is a simple matter to wire the yard, and for your purpose, you would only need to gap one rail, but with DCC, I'd probably gap both rails just to be sure.

Now if this were a visible yard, I'd keep all of the locomotives powered up as that would be most prototypical.

ROAR

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Posted by DigitalGriffin on Thursday, December 3, 2015 10:17 AM
Yes. You can use a method similar to power routing a yard where only the active yard track (the one attached to the ladder) has power

When i say attached to the lafder i mean points on the ladder switch thrown to the desired track

Don - Specializing in layout DC->DCC conversions

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Posted by gmpullman on Thursday, December 3, 2015 10:47 AM

mlehman
Up to the limit of the contacts on the Tortoise.

Mike, I remember looking up the contact rating on the Tortoise for another thread a while ago. If I recall it was something around 4-5 amps "static load" so that runs pretty close to your estimate.

From Circuitron:

What is the current rating of the TORTOISE’s™ internal switches?
The two internal SPDT switches built into the TORTOISE™ are rated to SWITCH one amp loads.  However, these switches will CARRY 4-5 amps without problem.  Since they are used primarily for static frog or siding power and are not actually switching the locomotive load,  no contact arcing will occur and the one amp rating is not an issue.  

 

Bernard,

There are some application notes for the Tortoise here that may help answer some questions:

http://www.circuitron.com/index_files/Page635.htm

Have Fun! Ed

 

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Posted by mlehman on Thursday, December 3, 2015 12:12 PM

Ed,

Yeah, sounds like what I must've been trying to remember with my general caution. Having the specifics is useful. Gotta also keep in mind that most sound engines have capacitors, so when you throw a switch to a track with several sound locos on it you will get a brief inrush current as they charge. Should be OK if it's on 4 or 5 locos, but you could start running into issues with more. It is brief, but still might eventually pit or zap the contacts if close to or goes over the max regularly. Having a properly adjusted circuit breaker on the power to the staging can help with this.

Mike Lehman

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Posted by maxman on Thursday, December 3, 2015 12:28 PM

If I were really concerned about shutting off the power to hidden tracks, even with DCC, I think I would rather depend upon toggle switches to do that.

The problem with having everything powered with the turnout motor contacts is if one set of contacts has a problem then the problem cascades down from there.

Also, if someone forgets to turn the throttle to zero before throwing the turnout to the next track, the next time someone switches back to that track the train may start to move before you're ready.

Plus if one were to follow the recommendation that every three feet or so of track has a feeder, then your staging tracks would be powered anyway.  Might as well feed the power through a toggle.

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Posted by trafficdesign on Thursday, December 3, 2015 2:14 PM

DigitalGriffin
Yes. You can use a method similar to power routing a yard where only the active yard track (the one attached to the ladder) has power

When i say attached to the lafder i mean points on the ladder switch thrown to the desired track
 

It sounds like a lot of you are suggesting that I use the points on the turnout to route power to the stub-ended tracks. My guess is that if I do it this way you are saying that I would not power the tracks with feeders.

BUT because the staging tracks are going to be quite long and I like reliable power, I was planning to drop feeders on every track section. So.... Can I use the tortoise to turn on and off the power to these track sections?

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Posted by rrinker on Thursday, December 3, 2015 3:29 PM

 I would consider using a relay with heavy duty contacts, the relay being controlled by the Tortoise contacts. As has been stated, the switching current rating of the Tortoise contacts is much lower than the carrying capability, so using the contacts to power tracks containing multiple sound locos on and off can easily exceed those ratings, at least with sound decoders because of current inrush issues. Once switched it would be fine, but that's besides the point. A relay controlled by the Tortoise contacts, since the relay would be relatively low current, with contacts rated high enough to handle the expected load of the locos sitting on the tracks, would avoid these problems. Of course so would using a toggle switch to turn off the staging tracks.

 Now if each track will only have a loco, or maybe 2 doubleheading a train, the Tortoise contacts should be fine.

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Posted by trafficdesign on Thursday, December 3, 2015 3:57 PM

rrinker
 Now if each track will only have a loco, or maybe 2 doubleheading a train, the Tortoise contacts should be fine.

Yes that is my plan. 1 train per track. Max 2 locos per train.

So how would I go about wiring the tortoise contacts to control the track power (and not just power routing through the points). Can someone walk me through it - preferably with pics or diagrams. I REALLY am an electronics idiot.

 

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Posted by rrinker on Thursday, December 3, 2015 5:22 PM

 There's a nice picture in the Tortoise instructions that show how the contacts work and where you connect the wires. Worst case, you get it backwards and the track the turnout is lined to is powered off and the other track is on.

 Insulate both rails off each leg of the turnout, tie all feeders for a given track together with a bus and that connects to one side of each contact (2 wires, 2 rails). The part of the switch shown in the picture with the arrow, that's the center contact and that goes to your DCC power. Tortoise moves one way, the center pins of the contacts (DCC power) connect to one side of the switch (the staging track)

                           --Randy


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Posted by mlehman on Thursday, December 3, 2015 5:25 PM

With one or two locos per track, you'll be fine. While I understand the cautions about exceeded the current carrying capacity, I've set my yard so the turnouts in each throat of a double-ended yard are all power routing, BUT...

The yard tracks themselves are all LIVE all the time. Yeah, you make a habit of returning your throttle to zero, but that's a habit you should develop when leaving a train or powering up a throttle and assigning it to control a specific loco.

It's all done with Tortoises, except the yard tracks are simply wired through one of the adjacent blocks. Right now, I'm not even sure which one. It has a toggle, to be sure, but had no problem so no need to worry too much about it.

Leaving the yard track live all the time eliminates needing to feed power from the Tortoise contacts. It eliminates needing to draw power alternative according to the turnout at either end being different.

If your tracks are all stubs, then I'd just go for power routing the whole siding through the Tortoises.

If double-ended, consider that's worked well for me, but also demands the discipline to keep things sorted  out and only use one route at each end at a time to avoid conflicts. You can go ahead and use power routing and gap the yard tracks in the middle. BOTH turnouts need to be aligned into the track to get the loco entering all the way to the far end, but Macro commands make that easy. But to avoid that, I just made the yard tracks on and confined the power routing at each end to the turnouts in the yard throat.

You can obviously have the best of both. Set up power routing as you like, then add the switches before the feeder to each track. Leave them on unless you want to kill a track and the power will still route just fine, plus it gives you the ability to shut the power down as you choose.

Mike Lehman

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Posted by MisterBeasley on Friday, December 4, 2015 10:42 AM

These are Atlas turnouts, so I don't think you can use traditional "power routing" through the turnout's points or the frog to control power on the diverging track.  These turnouts have internal jumpers so power is always delivered through both rails on all three tracks if any of them is powered.

So, you will need to gap one track on each siding and provide a feeder wire through the Tortoise.  For reliability, you will want to power the frogs, too.

I've got a similar situation with a 5-track staging yard.  I used one set of Tortoise contacts on each turnout for frog power, and I put a dual-color red-green LED in series with the Tortoise power for a control panel indicator.  I just went the easy route and used panel toggle switches to control track power.

One issue with powering a ladder like this is that you need to set a series of turnouts to select the track you want.  Unless you've got them wired for DCC route control, you'll be setting them manually, one at a time, and as you do that you'll find your engines momentarily powering up as their tracks are powered and then unpowered as you go through the sequence.

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Posted by DigitalGriffin on Friday, December 4, 2015 10:58 AM
You could use the points to power the yard track. If the points arent making contact with the stock rails the engine will likely stall on the turnout anyway.

We did track yard power routing at a club i maintained the electrical work on before they went dcc. HOWEVER using a relay like those built into the tortoise are much more reliable.

Don - Specializing in layout DC->DCC conversions

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Posted by rrebell on Friday, December 4, 2015 11:22 AM

Just use micro toggles' less work and more positive control, in fact you can power the yard tracks as two separate items if they are realy long alowing two stored engines on one track, seen this done on DC.

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Posted by mlehman on Friday, December 4, 2015 11:45 AM

MisterBeasley
These are Atlas turnouts, so I don't think you can use traditional "power routing" through the turnout's points or the frog to control power on the diverging track. These turnouts have internal jumpers so power is always delivered through both rails on all three tracks if any of them is powered. So, you will need to gap one track on each siding and provide a feeder wire through the Tortoise. For reliability, you will want to power the frogs, too.

Yeah, that does make a difference. In this case, you can just gap after the divergence and either power it through control via the set-up you describe or just independently via a switch.

One thing to keep in mind about having swicthed tracks in hidden staging. In operation, you generally will find it easier to let the turnout do the thinking for what you don't see in preference to having to also throw a switch to power the receiving yard track. If you default to keeping power on the tracks, then you won't get the sudden halt that comes with running into dead rails. That's why I suggested using switches to shut down the yards tracks only as an option, rather than using that as the default mode.

All this presumes DCC. Obviously, with DC you have no choice but to kill track power in the yard tracks unless you want the train to move.

Mike Lehman

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Posted by DigitalGriffin on Friday, December 4, 2015 12:27 PM

I agree.  The turnouts you use does make a difference.  

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by MisterBeasley on Friday, December 4, 2015 1:01 PM

rrinker
There's a nice picture in the Tortoise instructions that show how the contacts work and where you connect the wires. Worst case, you get it backwards and the track the turnout is lined to is powered off and the other track is on.

For reference:

The thing that trips some people up is that contacts 2-3-4 and 5-6-7 form two separate single-pole, double-throw (SPDT) sets, but the common posts are not 3 and 6, the center ones, but rather 4 and 5.

It takes an iron man to play with a toy iron horse. 

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Posted by trafficdesign on Friday, December 4, 2015 8:09 PM

MisterBeasley
For reference: The thing that trips some people up is that contacts 2-3-4 and 5-6-7 form two separate single-pole, double-throw (SPDT) sets, but the common posts are not 3 and 6, the center ones, but rather 4 and 5.

To recap, I am using Atlas Code 100 Customline turnouts (non-power routing). My layout is DCC. I'd like the Tortoise to control power to the yard track so that it is only 'live' when the turnout is set off the mainline to diverge into the track.

So given the diagram above, how would I power the track on/off using the tortoise contacts 2-4?

1 = 12V accessory bus +ve Power into Tortoise

2 = ?

3 = ?

4 = ?

5 = to Frog

6 = black track Power

7 = red track Power

8 = 12V accessory bus -ve power into Tortoise

 

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Posted by Anonymous on Friday, December 4, 2015 8:23 PM

Is this staging going to be accessible?  The reason I ask is because if (and its a pretty big if, but it happens) the tortoise fails for some reason, you no longer have a way to move that train out of the yard.  

Personally I will probably go with DPSTs 3p/st or 4p/st switches (my club disassembled an old DC control panel recently and I have some of these laying around) for turning tracks on and off, and providing panel indication of power to the track.

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Posted by rrinker on Friday, December 4, 2015 8:27 PM

2 to rail A of one siding, 3 to rail A of the other siding. 4 to track red. Rail B of both sidings to track black. Put an insulated joiner in rail A of each siding where it attaches to the turnout.

 If the wrong track is energized based on point position, swap the wires on 2 and 3. Same if the frog is the wrong polarity, swap the wires on 6 and 7.

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Posted by carl425 on Saturday, December 5, 2015 9:35 AM

Hi Bernard,

You don't mention whether or not you will be using DCC to control your turnouts, but in case you either are or will consider it, here's another option.

Many DCC stationary decoders and other devices either natively support or can be configured to drive a relay as if it were a turnout.  One of the advantages of using DCC to control turnouts is the ability to create table driven routes.  These tables list all the turnouts required and the direction they need to be set to set up the route. When you select a route (or in this case a track in the staging yard) the system looks up the route in the table and throws all the turnouts as required for selected track.  It is a fairly simple task to add one more "turnout" to the route table for each track and have it throw the relay that brings power to that track.

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Posted by DigitalGriffin on Saturday, December 5, 2015 9:47 AM

 

trafficdesign
 
 
 

 

To recap, I am using Atlas Code 100 Customline turnouts (non-power routing). My layout is DCC. I'd like the Tortoise to control power to the yard track so that it is only 'live' when the turnout is set off the mainline to diverge into the track.

So given the diagram above, how would I power the track on/off using the tortoise contacts 2-4?

1 = 12V accessory bus +ve Power into Tortoise

2 = ?

3 = ?

4 = ?

5 = to Frog

6 = black track Power

7 = red track Power

8 = 12V accessory bus -ve power into Tortoise

 

 

 

It can be a little frustrating trying to create circuits the first time.  But kudos for trying.

 

There's 3 ways to wire this up.  This is likely how I would do it:

Starting from the branch line or main switch going into the yard... 

Pin 1: Tortoise power 1. 

Pin 8: Tortoise power 2.  (provides the other connection to the motor to throw it)

Connect pins 1 and 8 to a DPDT switch OR a DCC turnout decoder.

Pins 4 and 5 connect to track power (on the first switch from main->yard only)

Pins 4 and 5 connect to pins 2 and 6 On the PREVIOUS tortoise (Does not apply to first switch)  For example pins 4 and 5 of yard ladder track 1 switch connects to pins 2, 6 of main to yard switch.  Pins 4 and 5 of yard ladder track 2 switch connects to pins 2, 6 of yard track 1 switch.  pins 4 and 5 and yard ladder track 3 switch connects to pins 2, and 6 of yard track 2 switch.

Pins 3, 7 connect to the yard track you wish powered.  (Not necessary for first switch that is attached to main)

Now here's where things may get a little "funny".  If you notice your yard track is not powered when you throw the switch, don't panic.  Simply swap pin 2 with pin 3, and 6 with pin 7!

If your system shorts as soon as you cross into the yard track, swap the wires to the yard track.

If you want to power the frog, let me know.  And I'll provide detailed instructions here.

Don - Specializing in layout DC->DCC conversions

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Posted by Guy Papillon on Saturday, December 5, 2015 2:08 PM

Others have already explained how to do it. If that can be of some help, here is how I wired a hidden 3 tracks yard using turtoise internal switches:

AC+ and L1, L2, L3 refer to wiring lights that indicate on a control panel which track is under power.

I first wired the layout for DC. I then must cut power on unused tracks. I choosed to keep this yard under block wiring when I converted the layout to DCC.

 

 

 

Guy

Modeling CNR in the 50's

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Posted by oltmannd on Tuesday, December 8, 2015 8:42 AM

Daisy-chaining up to four sets of switch machine contacts would make me a bit uneasy.  

How about a rotary switch?  Just dial in the track you want to power.  If double pole, you could also use it to manually power the switch machines through a diode matrix.

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Posted by rrinker on Tuesday, December 8, 2015 11:58 AM

 As long as it's a simple ladder and not a compound one, there wouldn't be any daisy chaining needed.

 Still, a simple on/off toggle for each yard track would be much simpler to figure out. Put an LED with a 1K resistor across the rails of each track to have another indication of which track is powered up - but if all the toggles are arranged the same way it will be obvious from the handle position.

                       --Randy


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Posted by trafficdesign on Wednesday, December 9, 2015 6:18 AM

rrinker

 Still, a simple on/off toggle for each yard track would be much simpler to figure out. Put an LED with a 1K resistor across the rails of each track to have another indication of which track is powered up - but if all the toggles are arranged the same way it will be obvious from the handle position.

                       --Randy

 

In the spirit of K.I.S.S. I am now leaning towards the toggle switch. Thanks for the LED idea, clever!

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