SSPRR Run Room

Playing with Toy Trains

Circuit Protection for Toy Trains - Photo Sequence


All power feeds from toy train transformers must have circuit protection in the line.  Use the lowest value protection that will hold the circuit closed.  Track for passenger cars will require the highest value protection.

Power Hazard symbol Protect you, your house, trains, wire, and accessories. Transformer internal breakers protect transformers, NOT trains. Shorts or faults can damage your toys and burn down your house. Circuit protection on the low voltage side of transformers is the same as having breakers in the circuit box for your house wiring.

Circuit Protection Sequence from 14V Light Bulbs
to the 120V Electrical Panel

The A terminal powers a major track.  The B terminal powers several small accessory circuits.
The C terminal powers Z-Stuff switch machines.  The D terminal powers a beginner track.

The PTC Resettable Fuses (orange discs) automatically reset when power is shut off and fault is cleared.  The PTC fuses are really hot when tripped and can burn your finger.  The panel mount breaker switch shows a white strip when tripped and is manually reset when the fault is cleared.

Photos are for illustration purposes. Click on some photos for a larger illustration.
For links to expanded topics click on underlined topic.

5 - 18 V
14 V
13.5 V 
5 - 18 V
Gargraves Track   Light bulbs
Protect lamps and accessories in small groups. Smaller fuses/breakers protect small wires and modern electronics.
 Z-Stuff Switch Machine thumb
Switch Machines Wired in Pairs are Operated with One Controller.
See Wiring Below
Track with Lockon 
Note white phase tape on common wire.
Track Wire Taps 
The MTH DCS TIU below is Optional.
Lamp Section Terminal 
See Scenery as a necessary evil.
Switch Machine Taps  A beginner track is best protected with a 3A Panel Mount Circuit Breaker .  The beginner can see the trip indicator and reset when fault is cleared. 
Inputs must have fuse/breaker in line from transformer.
Town Section Wire Drops 
Protection for 5 Lighting Sections (1.6 A each)
Z-Stuff Machine Breaker 
1.6 A Switch Machine Protection
Breaker Switch 
see Breaker Tripped

This sample terminal strip shows wires from transformer, power going through the PTC fuses, power out to load.  The color code is black, red, blue, and brown.  Phase tape is used when correct color wire is unavailable.
Yellow arrows point to transformer terminal wires.  Orange arrows point to load terminal wires.

Transformer Wire Terminals 

Lionel Postwar ZW Transformer

ZW Breaker 
Transformer Breaker is Buried Under the Wiring.
 ZW Connections
Ring terminals crimped and soldered to wires are helpful.
ZW Transformer 

See Transformer Ratings and Connections
Postwar transformers are derated 80% when in use.

Plug the transformer into switched grounded plug strip and scenery can be shut off when guests are not present.  Extension cords should be 16 gauge 3 wire grounded for modern electronics.  The Trolley control is plugged into the extension cord so the trolley runs when the town lights are off.

Switched Plug Strip  120 V Duplex Receptacle and Plug 
One of 8 Plugs on 15A 120V Breaker

The bottom of Run Room duplex receptacles are controlled by a wall switches.

Basement 120V Electrical with 15 Amp Breaker Noted

120V Basement Electrical Panel

Reference Links

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