home
back

Wiring part 2 : Turnouts

On this layout, I use two kinds of switches, the code 83 Tillig ELITE and code 83 ROCO LINE.
Here are two apparently identical switches, deflection angle 15 °, length 228 mm for Tillig and 230 mm  for Roco.
However they are very different in both mechanical and electrical design.

Another option is chosen for this layout, I operate turnouts by mini control panels distributed all along the track.
This layout will not be equipped with computerized control system, the DCC signals will not be used to control the switches.

The DCC will be described in detail on the Technical / Wiring  Part 3 page.

This page is partly inspired by the work of Allan Gartner with his kind permission.
Visit his website about wiring and DCC, garden train and much more : Wiring for DCC (see links page).


Turnout terminology


T : Throwbar
 
P : Point rails

C : Closure rails

S : Stock rails

G : Gard rails

F : Frog

F - P : Frog point

Gaps : frog isolation

Pivots : Hinge of the point rails

cablage_02_00
Clic on picture to enlarge


Overview of the switches


At the top,The TILLIG switch with flexible closure rails, there is no  mechanical or electrical discontinuity between the point rail and the closure rail.




Below, the ROCO switch with discontinuity between point rail and closure rail, they are jointed by a "hinge".
They are interrupted mechanically and electrically and are connected by friction.
This second configuration represents the majority of switches available on the market.


cablage 02_01
Clic on picture to enlarge


Electrical operation of the switches

Note: The colors blue and red are not the wires color connected to the switch.
They are simply used to differentiate the "polarity of different parts in order to illustrate the operation.
Small red and blue lines on the far right of the switches represent the "polarity of the rails that will be connect to it.

TILLIG :
B
: Closure rail and the frog (pointe de coeur) are  electrically connected.
It should therefore take two precautions:
A : limit the thickness of the wheel flanges to avoid short-circuits between the point  (green) and the stock rail (red). The switch is designed for the wheels defined as the NEM 310 and 311 (see MOROP on Links page), for older vehicles. . you'll have to test !
C : Use insulated rail joiners to prevent short-circuit with the next rails.

ROCO :
E : point rail and frog (pointe de coeur) are electrically isolated.
No danger of short circuit between the point D and the stock rail because both of them are the same potential.
F : no risk of shorting the next rails.

P : the pivots ensure contact between the point rail and the closure rail.
cablage_02_02
Clic on picture to enlarge


TILLIG


Switch in  "straight" position :
The point is in touch with the blue rail B
The point rail must be polarized blue and it is close to the stock rail polarized red. A
The frog C must be isolated from the next rail to avoid a short circuit.

Switch in "deflected" position :
The point is in touch with the red rail D
The point rail must be polarized red and it is close to the stock rail polarized blue. E
The frog F must be isolated from the next rail to avoid a short circuit.

Summary :
1 - there should reverse the polarity of the point rail according to its position.

2 - there must isolate both ends of the frog
C and F by means of insulated rail joiners to prevent a short circuit with the next rails.



cablage_02_03
Clic on picture to enlarge



Bottom view : here is the wiring corresponding to the TILLIG switch

The blue and white wires feed the stock rails.

The green wire feeds the frog and the closure rails through an inverter which determine polarity depending of the switch position.

This inverter must imperatively be mechanically linked to the movement of the switch.
cablage_02_04


ROCO

Switch in  "straight" position :
The point A is in touch with the blue rail
The point B is polarized as the red stock rail close to it => no risk of short circuit.
The frog C is isolated from the rest of the switch and must be polarized blue.

Switch in "deflected" position :
The point D is in touch with the red rail
The point E is polarized as the blue stock rail close to it => no risk of short circuit.
The frog F is isolated from the rest of the switch and must be polarized red.

Summary :
1 - there should reverse the polarity of the point rail according to its position.
2 - It is not necessary to isolate the two rails end of frog.
3 - The pivots P provide electrical continuity through friction.
cablage_02_05
Clic on picture to enlarge



Bottom view : here is the wiring corresponding to the ROCO switch

The blue and white wires feed the stock rails.

The green wire feeds the frog and the closure rails through an inverter which determine polarity depending of the switch position.

This inverter must imperatively be mechanically linked to the movement of the switch.
cablage_02_06



Focus on the pivots.

Note that only the friction, maintains contact between the point rail (bottom) and the closure rail (top).

Despite the good characteristics of the nickel silver it is feared the advent of bad contacts over time.

cablage_02_07



These same pivots viewed from below.

To avoid the appearance of bad contacts, I make two jumpers from 0.4 mm ² wire between the point rail and the closure rail.

Note the Z-shaped to increase the mechanical elasticity of this jumper.
cablage_02_08


Motorization of the switch

Whatever the type used, we have seen that the polarity of the frogt must be reversed depending on the position of the switch.
To make this reversal of polarity, several possibilities exist.
On most motors referrals, there is an inverter controlled by the movement.
On this layout, I chose to use LEMACO - LEMATEC motors (see Links).
These motors are providing a relatively slow movement and very good electrical contacts.
Their drawback is the sound of running fairly large and very difficult to reduce.
Other types of motors will be discussed later, notably a "home made"motor with memory wire.

This "home made" motor will be built from material sold by Jacques Le Plat (see Links)




Mounting of the LEMACO motor.

The mechanical command is composed of a  rudder ** (from model airplanes) as well as a piano wire of 0.6 mm "Z shaped" to absorb the displacement difference while applying light pressure to the point .

Note the 4 inverters with:
2 are used as "limit switches" for the motor
2 for the polarization of the frog.

With a slight modification of the motor wiring, it is possible to use the two "limit" inverters to display the position of the motor on the control panel.

Also note that each switch is wired with color code following my principles of wiring.

** Rudder: black piece cross shaped
cablage_02_09



As recommends the manufacturer, you can reuse the plastic packing to cover the motor.

This will protect from dust and keep the contacts in good condition.
cablage_02_10



Here are two switches with "deported" control.

This allows to set the motors in convenient locations to facilitate maintenance.

I was able to deport a motor up to 1 meter from the controlled switch.

In this case, I use a brass tube of 1mm internal diameter on which I weld mounting tabs and a piano wire of 0.6 mm.

During assembly, I apply a silicone lubricant on the piano wire before inserting it into the tube to prevent corrosion.

Note that each motor is equipped with a 9 contacts SUB-D connector  to facilitate maintenance. All motors are thus easily interchangeable.
cablage_02_11


Detailed assembly of the rudder



Here are two types of rudder: 30 and 40 mm.

A piano wire of 0.8 mm, length 80 mm is bent with the rudder's hole spacing (3mm).
This needle will be cut after assembly, flush with the throwbar of the switch.
The rudder and the needle are mounted on a plywood support during bonding.
The epoxy glue is prepared with a toothpick on a piece of paper (no tools to clean).

Detail of bonding : the needle is stuck during the polymerization of the glue, the piece of yellow paper under the bonding prevents the rudder to be glued to the bonding support.

Details of the axle: a screw M3 x 25 retained by a washer and nut on the track plan, the white washer supporting the rudder is made from a 1mm thick sheet styrene.

cablage_02_11_acablage_02_11_b
cablage_02_11_ccablage_02_11_d



Assembly completed !

The adjustment of the torque is greatly facilitated by using a locknut.

However, if you do not have this type of locknut, you can replace it with two nuts.

The rudder and locknuts are available on a model aircraft retailers  such as
Mantua  Model Center (see Links).

The locknuts are also available from
RS Components (see Links)
cablage_02_11_e


Wiring of the motor control


Here is a small modification to the motor before wiring it in order to display its position via the "limit switches".

Remove the white wire visible on both photos on the left and clean the contacts from traces of soldering.

You see the result on both pictures on the right.
cablage_02_12cablage_02_13
cablage_02_14cablage_02_15



Here are the different terminals to be wired with their wires number and color.

Each wire, after welding, will be isolated by means of shrink sleeve.

On my layout, the terminal numbers also correspond to the numbered pins of the SUB-D 9 pins connector which equips each motor. (easier wiring)

The colors here represent my color code, feel free to set another code if you wish.
cablage_02_16



Wiring diagram of the motor:

The motor is powered by 12V AC.

The red and green LED's give the position of the turnout.

The wiring does not pose any particular problem except maybe for the connection of the white wires (4-6) to DCC bus.

For this operation, see below.

cablage_02_17

Wiring of the frog

For this example the bus that feeds the district is Blue - White.
Your switch must be in place and the motor has to be mechanically connected to it.
The DCC booster has to be disconnected from the rails.
No consumer should be on track in this district (locomotive, wagon with lights, etc....)
Connect the control and the power supply of the motor. (terminals 1, 2, 3, 7, 8)
Connect the frog to terminal 5 of the motor.
Connect the stock rails to the district bus (Blue - White)


1 - connect a ohmmètre between white and blue track and measure R> 100 ohms, if lower:
there is a consumer in this district !

2 - activate the motor for positioning the switch "straight".

3 - Connect an ohmmeter between the point rail (green) and successively the wires from the terminals 4 and 6 of the motor.

4 - connect the one that have R < 10 ohms, at the blue wire of the bus.

5 - activate the motor for positioning the switch "deviated".

6 - check R < 10 ohms between the point rail (green) and the wire remaining.

7 - Connect this wire to the blue wire of the bus.

8 - Connect a ohmmeter between white and blue track and measure R> 100 ohms, if lower:
you must check your work !

cablage_02_18
Clic on picture to enlarge


Note : For the ROCO switch, the procedure is exactly the same except for step 3:
the meter should be connected to the frog instead of the point rail.


The turnouts control panel


Example of control panel for controlling and viewing turnouts position.
It is made of aluminum 2mm thick.

This will control the "alpine station"
it controls four turnouts and an electro-magnetic uncoupler.

The toggle switches control the turnouts position.

The green and red LED's are showing their  position:
- green = staight
- red = deflected.

The red push button is controlling a electro-magnetic uncoupler.

cablage_02_19



Rear view of the "alpine station" control panel.

Note the setting of LED's with epoxy glue.

Blue terminals will support the resistor (2K7) limiting the LED's current.

Top right, see a two-color LED (3-terminal) that inform me about the occupation of the hidden loop and its input signal.


cablage_02_20


home
back