Has anyone used a diode or diodes to lower the volatage on a down grade, on a figure eight over & under. This would be with conventional engines.
thank you MONK
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Yep, but you need back to back diodes for AC. It should drop the voltage about .6-.7 volts for each diode pair.
I haven't actually tried this myself because I like to ride the throttle on my grades, but there could be some "gotcha's". When the locomotive hits the top of the grade, it is still pulling the rest of the train up the hill. If you drop the voltage at the crest, there may not be enough power for pulling the rest of the train up. Also, this helps in one direction only, but you could use a double pole, double throw switch to exchange the power between the uphill and downhill sections when you reverse direction.
Originally Posted by gunrunnerjohn:
Yep, but you need back to back diodes for AC. It should drop the voltage about .6-.7 volts for each diode pair.
I have used one diode to triger the stops on a gallopping goose, it slows down fine with one diode.
thank you MONK
I use 25 amp bridge rectifiers. Explained here
www.jcstudiosinc.com/BlogShowT...3&categoryId=426
The problems Dale mentions can be managed with a relay system and made bi directional if need be.
Dale H
TMCC with Cruise Control. 
Originally Posted by gunrunnerjohn:
TMCC with Cruise Control.
$$$$$$$s
Dale H
I faced the same problem on an earlier layout. Too slow going uphill and too fast going down. I connected the B and C fixed voltage power from my PW ZW to connect to the uphill block and the down hill block via a DPDT center off toggle switch. That way I could drive and also put in "auto" mode when desired. I had to toggle the switch based on train direction for auto mode or put it in center off for me driving.
I know that this approach does not fit the diode question as asked, but it might be useful to somebody.
