Train Speed Limiter

Picopirate

Does anyone have any good designs to limit the speed of trains? Last night, after building the engine for the #3677, my son cranked it and the train derailed and fell off his train table. A few pieces came off but nothing was damaged.

This morning, I threw together the following solution, but I was hoping someone might have a better design.
http://www.flickr.com/photos/91931091@N02/8387006780/

CCC

More load on the engine will obviously help slow it down.

Or maybe build a gear rig above the speed control coming off the technic pins at the side, so that one turn of the upper cog-wheel only partially turns the speed wheel. It won't limit the speed, but it would slow down how fast he cranks it up. I haven't tried it, but it is probably possible.

cheshirecat

Or, run it around for 10 minutes and then the batteries will have gone enough to slow it down some.

Adding lights (if you can with that train) might also have the desired effect.

graphite

Ideally the best way to regulate the train speed since some trains have more load than others, would be for there to be an adjustment on the IR receiver so that the max PWM pulse to the motor could be limited/adjusted. There are a few websites where people have made their own receivers and such, so a DIY receiver would be possible to accomplish that but I would highly doubt LEGO would ever release one as it would up the cost of the receiver. Not by much probably but still is extra work on their part.

ColoradoBricks

Another solution and not really a design, but if you use a rechargeable battery (#8878). You can limit the output on it. So you set it to 4 out of 7 there, even if the controller goes to 7, speed 4 is all you get on the train.