Operating Trix-Twin

Wiring two controllers for twin-running

Twin train wiring

  • T is a transformer capable of providing 14 volts AC at 3 amps. If you have a Trix Master Switch plugged into the transformer, connect the wires to the sockets marked A C A as shown.
  • If you do not have a Master Switch, join both wires marked A together. Then plug A and C into the outer (14 volt) sockets on the Transformer. Do not use the centre socket.
  • If you do not have a Trix transformer, join both wires marked A together, and connect A and C to any transformer that supplies 14-16 volts at up to 3 amps alternating current.
  • See the diagram at the bottom of this page for wiring points and accessories.
  • There are special Trix plugs which make connections to track and controller reliable and easy.


TTR Master Switch

TTR post-war Controller


Running two locos

Twin train wiring

This diagram shows wiring connections from Power Supply to two controllers for twin-train running. Note that the locos pick up current from the centre rail and different outer rails. The switch on the controller changes the direction of the loco. Click once and the loco goes into neutral, again and the loco reverses. A worn or dirty reversing mechanism will result in the loco buzzing or refusing to change direction.

More detailed explanation


T is theTransformer. It reduces the high voltage (240v) of the A.C. house mains to a value that is both safe and convenient for operating the train (14v).

R is the controller. Current must pass through this controller to the track to run the locos. The black knob K regulates the amount of current supplied by the transformer, and makes a loco on the track go faster or slower. The key U to the left of this black knob K, causes the loco to stop and to reverse its direction of travel.

It will be seen that current is supplied to rails 2 and 3, therefore the loco is placed on the track facing in that direction which will bring its side shoes into contact with rail 3.

Switching on the current and turning the resistance knob about half way round to the right will start the loco.

To stop the loco it is necessary to interrupt the current (key U). This will cause the locomotive to stop. With a second interruption the locomotive will move again, but this time in the opposite direction. A third will stop it, while a fourth will cause it to run again in its original direction, the speed of running in each direction being controlled by the resistance knob.

If the loco is lifted from the track and faced in the opposite direction, the above operation has no effect since there is no current at present being supplied to rail No.1.

If, however, the plug is taken out of the right-hand (blue) socket on the terminal rail and put into the left-hand (white) socket, the loco will work again.

The three sockets on the terminal rail in Fig. 1 are connected as follows

The left-hand (or white disc) to rail No. 1.
The middle (or red disc) to rail No. 2.
The right-hand (or blue disc) to rail No. 3.

Make sure that the wire marked C goes direct from the power supply to the middle socket on the terminal rail which is identified by a RED disc.


Steam locos are provided with a safety valve which is set to blow off if the boiler pressure exceeds a certain value. This saves the boiler from bursting.

Trix locos, of course, are not steam driven, but all the same their motors must be protected. Therefore, within your controller is a device which automatically protects not only the loco and the transformer, but also the controller itself from the effects of overload and "short circuit." This cut-out is, in fact, an electrically operated safety valve, and if for any cause the current flowing in the circuit is excessive, the safety valve operates and immediately the key U will jump from its normal vertical position into a sloping position towards the words " Cut Out "; current in that circuit is then completely cut off. No current will flow again until the key U has been restored to its vertical position. If, therefore, your key U "trips" and springs forward with a click, it indicates that there has been an overload on that circuit. In this case centre the key again. If it stays in its normal position the cause for tripping has righted itself.

If, on centering, the key " trips" as soon as the finger is removed, it means either that there is a short circuit on the track somewhere (e.g. some metal object resting across the live rails) or that the loco is taking excessive current through being overloaded with too many vehicles, or because it needs oiling or cleaning.

To determine if the cause for tripping is in the loco or the track, remove the loco and centre the key U. If it stays at centre but immediately trips again when the Ioco is replaced, the fault is in the loco. If, however, the key U when centered "trips" even when the loco is off the track, then the short circuit is on the track and must be found and remedied.

Each time a suspected short circuit is put right, centre the key and when finally the trouble has been corrected it will stay vertical in its normal position. The key U is also needed for changing direction of the train.

ON NO ACCOUNT HOLD THE KEY U IN THE CENTRE POSITION, as this is equivalent to screwing down a safety valve and is against all rules of engineering.


On full-size and model electric railways the conductor rails are subject to voltage drop. This means that the parts of the track which are remote from the source of current supply or main feed will not be receiving the same amount of current because the steel rails set up a resistance.

To overcome this use extra terminal rails, the centre contacts of which are wired to the "C" of the power supply. Boost rails should be inserted into the track at a distance from the main feed ; the number of rails to be used will depend upon the size of your layout.

Wiring Points and Accessories

In the diagrams below, Fig 2 shows connections when using two Trix variable power units.

Fig 3 shows two controllers fed from a transformer (no Master Switch) with an additional transformer wired to supply lighting. This extra transformer is not normally required, as a Trix transformer and Master Switch combination can supply several locos, accessories, and lighting.

I recommend that all supplies to accessories are fed from either a Master Switch or controller so that there is a safety overload cutout in the event of a short circuit. In Fig 3, a controller should be connected between the red switch and the transformer. This also enables the lamp brightness to be adjusted.

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