DC power supplies?

The thing I marvel at is the tolerance and trust my parents had and how much they allowed us.  I know several sets of modern "helicopter" parents who would go ape if their kid's train set started a small fire in the basement: probably buy them Nomex suits to wear and prohibit them from running them unless a hazmat team was on site.  Looking back, I'm amazed that my Mom and Dad let us go on, particularly given our pencant for experimenting with cool ideas like launching locos from a ramp clear across the basement into my mother's laundry basket, etc.  (That Marx 2-4-2 loco never failed, even though it was much the worse for wear from those times we missed). 

Anyway, I have to say that modern equipment is worth it.  The levels of protection in the ZW-L are awesome, and it truly seems "smart" with respect to understanding if it is seeing only a transient or something that does require it to step in and open the circuit.  Much better than fuses!

Hokie 71 and Stone Rhino thanks for the links to circuit breaker vendors. That's just the info I was looking for.  Lee, had a great laugh over your last post. What great images. :-)

Tomlinson Run RR

Oh, that's what the HO scale trains were for, not dad's big ones

And just think of Erector sets with all those small bolts and nuts. I remember getting my fingers caught in the open gears of the motor my set had more than once and actually drawing blood.

Scotie

Taught you to keep your fingers out of there though.  I remember.  Ouch!

Here's an update on protecting my models from my old Marx transformer.  Although a circuit breaker is probably the best way to go, my living room carpet-based setup is too unsophisticated for that.  So, for the short term I bought an inline fuse holder and put a 2.5 amp fuse it in. [25 watts = 6-12 volts x 2.083... amps.]  I'm an old rock musician who doesn't mind replacing fuses. :-}

To one end I attached a loop terminal to go to the transformer and the other end has a spade terminal to go to the MTH lockon.  As you can see in the attached photos, I'm still using a large gauge green grounding wire (I was using two of these -- one on each side, prior to adding the inline fuse).  So, even 'though that green wire size is overkill, is it OK that I have two different wire gauges now attached to the transformer?  The guy at my hardware store said it was OK but he also told me that my Marx transformer wasn't a "transformer" and insisted that it produced DC (!).  So, let me ask you experts:  Is this OK to have two different sized gauges?  It seems to run fine but then it always did. 

Also, can someone explain to me why if the current is alternating do I need an inline fuse on only one side?  Still a newbie with questions ... Thanks!

Tomlinson Run RR

P.S. -- I'm attaching pictures.  My MTH Pittsburgh Birney Trolley now runs at a much less frantic pace and no longer derails on 6-12 V max, versus 18 volts.

Also, can someone explain to me why if the current is alternating do I need an inline fuse on only one side?

A complete electrical circuit has to make the full circle from one side of the power supply to the other.  An interrupting anywhere in the circuit will cut off the power.  It's the same reason you only need to switch one power supply lead to kill the power.

Well, that makes sense.  Thanks, gunrunnerjohn. 

TRRR

I'm glad I was able to be of assistance