# Help - fiber pin use



## dooper (Nov 9, 2015)

Help please. I am setting up a new layout. I basically have two sets of track, a transformer for each, and two pairs of switches so one train can crossover and run on the other track.
Where are the fiber pins attached, and do I set my switches on normal operation or two train operation. I thank you in advance for any help you can give me.


----------



## rkenney (Aug 10, 2013)

Hopefully one of the S guys will chime in. The setup is pretty much the same as O. Your dividing the track into separate electrical blocks. 

The way to do this is simply to put an insulator on one side of the rails. This has to be consistent so for example if you call the negative terminal 'ground' it will be a common connection for all blocks and the opposite rail will be positive and separated by insulators in places to create isolated blocks.

Each isolated block will need its own positive feed (remember negative is 'ground' and common to all blocks). Typically you will use a switch to power (positive) each block feed from either of two or more variable power supplies (a dual control transformer). This way each engine on separate blocks receives its own voltage and direction level and two consecutive blocks can receive the same power to allow a train to pass between them.

There are lots of books on the subject with illustrations that may make it easier for you to grasp.


----------



## flyernut (Oct 31, 2010)

Just set the switch on the face to 2-train operation.


----------



## rkenney (Aug 10, 2013)

Boy...That sounds a lot easier!


----------



## DonR (Oct 18, 2012)

Hold on.

You should place the fiber insulated pins in both
rails between the two turnouts connecting your
two ovals. This isolates the two ovals from each other.

Also, S scale is AC so you must make certain your
two transformers are in phase else when the loco
crosses between the two tracks you would have
a short circuit. Once done use a power
strip so that the transformers are themselves not
unplugged.

Don


----------



## AmFlyer (Mar 16, 2012)

If you have 2 separate transformers and no reverse loops, no fiber pins are essential for 2 train operation. The turnouts should be set to 2 Train operation and when connecting the transformer to the track make sure the base posts are on the same rail where they meet at the turnouts and both of the 7-15V posts are on the other rail. The transformer primaries must be correctly phased. Wired this way one transformer will power both tracks when the turnouts are set to go from one loop to another but not otherwise. 
It you use a dual control transformer like a 12B or 30B where the base posts are connected inside the transformer then fiber pins are usually needed. It depends on the specific track layout and where the 690 track terminals are located. 
On my Christmas layouts I use a dual control transformer, no fiber pins and can operate two loops independently because all the power feeds (690 clips) are on the point sides of the interchange turnouts, not on the frog side. If there are power feeds on both the point side and frog side of the turnouts and a dual control transformer it defeats the two train turnout feature. Build a quick two loop track on the floor and try it out with different power feed locations, you will not harm anything.


----------



## DonR (Oct 18, 2012)

Tom

It's been decades since I had an A-F S gauge train.
I did have turnouts on it but don't remember anything
about them. Are you saying that A-F turnouts are
power routing if so set by the two train switch?

Don


----------



## AmFlyer (Mar 16, 2012)

Yes, the Gilbert turnouts are power routing when the slide switch is set to 2 train. That is a really nice feature. It almost makes up for the fact that 2 rail reverse loops were so hard in the days before automated sensors.


----------



## DonR (Oct 18, 2012)

Tom

There was a thread a short way back regarding
reverse loop controllers that would work with
2 rail S AC tracks.

Seems to me that a DCC reverse loop controller
would work. They're designed to be powered
by around 12 to 14 volts modified AC. When
they detect the loco wheels shorting they flip
phase (polarity) of the isolated section using a relay.
Since they don't interrupt power there would be no effect on the 
E unit.

Be interesting to try one.

Don


----------



## dooper (Nov 9, 2015)

As Gomer Pyle used to say, Thank You, Thank You, Thank you. 
Now, I am going to add several spurs that I want powered so my 322's can smoke in the yards. I assume that I put a fiber pin in the variable side and leave the base tracks connected. Would this also work on a siding so a slower train can be pulled over?


----------



## flyernut (Oct 31, 2010)

dooper said:


> As Gomer Pyle used to say, Thank You, Thank You, Thank you.
> Now, I am going to add several spurs that I want powered so my 322's can smoke in the yards. I assume that I put a fiber pin in the variable side and leave the base tracks connected. Would this also work on a siding so a slower train can be pulled over?


You don't need fiber pins in there at all. To have your Hudson sitting on a siding calmly smoking away, just change the switch position to 2-train operation, and add a lock-on to the siding, having it's own power source..That's what I do with mine.


----------



## AmFlyer (Mar 16, 2012)

Don, The DC/DCC boards should not be used with AC track power. I have 3 reverse loops on my permanent layout, the auto reverser boards are part number PSX-AR-AC.


----------



## dooper (Nov 9, 2015)

flyernut said:


> You don't need fiber pins in there at all. To have your Hudson sitting on a siding calmly smoking away, just change the switch position to 2-train operation, and add a lock-on to the siding, having it's own power source..That's what I do with mine.


Thank you sir. Does anyone want to buy a bunch of fiber pins:appl::appl::appl:


----------



## DonR (Oct 18, 2012)

Tom

I remember you or another mentioning a
suitable reverse loop controller for S gauge
but didn't remember the device.

However, I'm still curious about whether
the DCC reverse controllers would work
on the S voltage. They are designed to work
on modified AC track current.

Also, is there no way that Transformer A power
can get through the turnouts to track B which is
powered by Transformer B no matter which
way the turnout switch is set. It seems to me that
fiber pins between the turnouts would be
an ounce of prevention.

Don


----------



## AmFlyer (Mar 16, 2012)

Don, I think one of the differences in the boards is the Amperage rating. Each reverse loop on my layout connects two different power districts, each of which is powered with a separate 10A channel on the ZW-L's. In a DCC setup I understand there to be one 8A supply unless a more elaborate installation of boosters is installed. Also in the HO DCC installations it is not likely a set of engines in the reverse loop is pulling 6 to 8A as it triggers the board.
Putting in fiber pins is always a guarantee of loop independence. However it defeats the ability of a single transformer to automatically power parts of a layout such as full train long interchange tracks. By leaving out the fiber pins I can power that interchange track from either loop depending on how the turnouts are thrown. It does require careful placement of the 690 track clips. In the past I have built complex multiloop layouts where either transformer could power a train over the entire layout when the other engines were behind a siding turnout. The loops would also run independently when the turnouts were thrown. Never used a fiber pin for other than isolation control of a track at crossings to prevent collisions. The turnout position controlled the semaphore that powered that isolation section. It is amazing what can be done with the original Gilbert devices. They were engineered with features beyond what most children and parents ever used.


----------



## DonR (Oct 18, 2012)

Well, that's what happens when it's been several decades
since the last time I laid hands on an S gauge train.
I forgot all about the amp draw. Way more than HO.
However, one last gasp thought. The Bachmann reverse
loop controller uses a relay to flip phase. That could
possibly handle the S loco draw.

Anyway, it's fun to have a conversation about it.

Don


----------



## AmFlyer (Mar 16, 2012)

Don, I am not familiar with the Bachman controller. If the contacts are designed for 10A then it might work. 
Just for amusement here is a picture of one of the PSX-AR-AC reverse loop controllers under the layout. The large heat sink on the board is visible. The output wires visible are 14 gauge. 
Sorry about the thread hijack. But this controller does require gaps or fiber pins in both rails.


----------

