Preventing Wrong-Way Entry Into a Turnout

[RicZ]

I am a bit confused (as always) about how to best prevent a "wrong-way entry" into a turnout.   Paul Harman's contribution to Alan Gartner's Wiring for DCC always shows an additional switch to supply power to isolated rails on either side of the turnout .  (see http://www.wiringfordcc.com/switches.htm) Circuitron's Tortoise manual does not provide a clear option for this need.

I use Atlas turnouts and have utilized the first aux switch to poower my 3-legged bi-polar LEDs.  If I read the manual right, I will need both aux contacts to individually power the appropriate isolated rail, leaving the other isolated rail "dead" until the turnout is throw in the proper direction.

One option appears to be to wire each isolated rail to the appropriate point rails.  Would this work, effectively?

 

RicZ

[locoi1sa]

  Powering from the point rails would not be recommended. Contact area would not be sufficient for a power hungry loco or a short/ derailment. There should be enough contacts on your tortoise machines for power routing? If not you can piggy back off the signal system with relays. Do you power route your frogs? You can use the same contacts.

        Pete

[RicZ]

I do not power my frogs and tabs 2,3 & 4 on my Tortoise are occupied by an LED indicator.
RicZ

[fwright]

RicZ

I am a bit confused (as always) about how to best prevent a "wrong-way entry" into a turnout.

 

Let's back up a minute.  What do you really want to happen and why?

1. No special wiring.  With Atlas turnouts, the locomotives approach and can run a turnout thrown against them, usually resulting in a derailment.  The derailments are a wonderful training tool - eventually you learn to check the turnout before going through it.  With DCC, the derailment may result in a short circuit that shuts down the layout, providing even more reinforcement.
2. Lionel type wiring - the train trips some form of sensor as it approaches, and the turnout gets thrown automatically.
3. Your suggested mode, which is really modifying/wiring the Atlas turnouts to be power routing.  With DCC, the decoder may reset with power removed.  This is why power routing turnouts are generally not used with DCC.

#1 is the simplest, because it involves training operators to check things rather than implementing automatic logic to protect operators from themselves.  Atlas turnouts were specifically wired to avoid power routing, and the knowledge of feeders and gaps that are needed to wire a layout full of power routing turnouts.

You can use another set of contacts on the Tortoise to power the isolation sections if you really want power routing.

my thoughts, your choices

Fred W

[RicZ]

While I appreciate the training tool concept, the two turnouts that I want to use the power routing idea on, are hidden and thus operators cannot see them. A derailment in a tunnel or on a helix is far worse than a decoder reset.
I believe I still need both sets of relays to individually power each individual isolated rail, but one of the Tortoise relays is being used ( in DC-mode) to power my indicator lights. So now what can I do?
RicZ

[cacole]

DCC Specialties makes an automatic turnout control module called The Hare that may do what you want.  

Check Tony's Trains for information about this device.

http://www.tonystrains.com 

[ba&prr]

If you are using DCC the Hare will work. This plugs on the bottom of the Tortoise. My friend has one set up so if a train is on the diverging route on the turnout and headed for the frog and the  points are set for the through route, the Hare senses this and throughs the points the correct way.  This involves special wiring to the turnout and gaps in the rail I think.    Joe

[fwright]

If all the Tortoise contacts are in use, add a 12V DC relay - typically come with at least 2 sets of contacts.  Use one set of Tortoise contacts to throw the relay.  Use the relay contacts for any/all of the additional purposes, plus the function moved off the Tortoise.  I would use the same power supply for the relay as you use for the Tortoise.

You can use a single contact set for both isolated sections.  Only one path needs to be isolated at a time (which one depends on turnout position), and only one rail in each section needs to be isolated.  There is no reason to isolate and control both rails in the isolation section.

I didn't know you were dealing with hidden turnouts.  If the isolated sections are also hidden, I would be thinking about how to communicate what happened to an operator whose train suddenly "stalls" on a hidden section of track.

my thoughts, your choices

Fred W

[larak]

Hi Ric,

If you are using the Tortoise you do NOT need to use any of the contacts for the R/G LED. Simply wire the LED in series with the switch motor leads (1 or 8). This leaves both sets of aux contacts free for other uses such as track power routing or reversing.

Karl