How about teaching him how fast he's allowed to run the train?  Praise him for slow running and end the session for the day if he insists on full throttle.  He'll quickly get the message.

I put side boards on my layout to keep the train off the floor.

  You can put diodes in series. It takes two groups of diodes in parallel. One facing one way and one the other. I'm sure someone will draw a picture for you. You can get the diodes at Radio shack. i would use 1n4001's probably start with 4 in series, 8 total.  4 in series should drop the voltage about 3 volts.

  you can see the side boards in the photo. Don

All good ideas, thanks.  I'm not much of an electrical guy, so that was the area I was most curious about.

Add a mechanical stop to the transformer handle to prevent it from going beyond the point you feel is safe.  Maybe a piece of wood attached to the mounting surface will work.

Shown here for an engine but it can also be placed between the transformer and track.  

http://www.jcstudiosinc.com/Bl...=488&categoryId=

http://www.jcstudiosinc.com/Bl...=413&categoryId=

Dale H

I'd suggest more robust diodes than the 1N4001, I'd use at least 3A diodes, and preferably 6A diodes.

I bought these on the bay:

1N5364B MOTOROLA 33V 5W AXIAL ZENER DIODES

Each one reduced the voltage buy 3 volts.  I used it to reduce volts to a smoke unit.

Worked great.

Plug your transformer into a dimmer.  Keep it simple.

DONOT use a dimmer !!!  You can/will lose both the dimmer and the transformer. 

Hey, take the advice or not, but at most it won't work or will have unwanted side effects, and nothing will be harmed.  Any on-line advice should be taken with a grain of salt, and that includes hysterical warnings that everything will blow up for no reason.

Hi we have a cw-80 at our store and let the kids that come in an run the trains.

 What we did as a simple fix we put a screw as a stop for handle.

That way the handle can only go so far. 

A modern solid state type transformer could be damaged by a dimmer. The lower voltage could overload components forcing higher amperage into them for the same load.

On older type transformers with a simple primary/secondary it probably would not cause damage.

Dale H

Are you sure this is what you used?  I don't see how a 33V Volt Zener diode reduces voltage by 3V.  Perhaps you meant a 3.3V Zener? 

Also, the conventional method of dropping AC voltage using Zeners requires 2 in series and back-to-back or else you get an asymmetrical drop in AC track voltage and the bell or whistle will trigger.  But I can see how a single Zener could work in a smoke unit where polarity/symmetry is not critical or if the Zener is placed where the smoke unit was DC-powered.

You beat me to it Stan.

A simple approach to reducing the maximum voltage from a model train transformer is to use a step-down transformer along with the train transformer.  Just plug the step down transformer into a standard 120 VAC outlet.  Then plug the train transformer into the "120v OUTLET" of the step down transformer.  The voltage will then be reduced by 1/2.  So the maximum output voltage from a Lionel KW transformer would be reduced to about 10 volts.

See the attachment. This 100w unit is available on Ebay.

A 100W transformer is not sufficient for the KW unless it's very lightly loaded.

Another option that would allow full power is a 10A filament transformer bucking the secondary.

Instead of a fixed stepdown unit, I'd opt for a more flexible solution, these are very useful for a number of things.

The auto transformer that you have shown is a bit expensive. Around $75 on Ebay.

However the autotransformer could also be used in place of a standard hobby transformer when it is used with a "brick" to obtain a 20 VAC maximum output. 

The 100 watt step down transformer I have shown is available on Ebay for $17.

For running a single model train the 100 watt output would probably be sufficient. 

You'd get about 70 watts to the track, but that may be sufficient.

You can buy a used 7.5A Variac on eBay for as little $25, look through the completed listings.  IMO, that would be a better bet.  There is almost nothing that can go wrong with the Variac, but that electronic box can easily crap out, and is surely more fragile than the boat anchor Variac.