Power to idle locomotives on the layout


PrairieKnight

PrairieKnight

Active Member
I have read articles and viewed videos that suggest the power should be cut to the "engine track" on a layout while the layout is powered up and one or two locomotives are working on the layout and the rest are sitting idle on powered track. Here is a photo of the track (s) where engines sit while one or at the most two locomotives are moving on the layout:

Engine 1.JPG


Sorry about the poor quality of the photo. The two tracks I am thinking about isolating are the ones on either side of the two fuel tanks on the left middle portion of the photo. Currently, I power up the layout and turn off the sound to the four locomotives that will be idle during a particular operating session. Does this practice harm the DCC components on the four Walther's Proto locomotives that sit unused?

While I do not think isolating the two tracks would be hard..... I have no idea how to wire in a toggle switch that would isolate the two tracks. I am using the NCE Power Cab system. In other words, I would need the book "Isolating engine tracks for dummies" to do this. Any advice or suggestions are greatly appreciated.
 
Technically, you'd only need a pair of insulated rail joiners to isolate one rail only, a piece of wire, and an on-off switch. Just use the insulated joiner on one rail, one either end of it, connect the wire almost anywhere in between, connect that to an on-off switch, then connect that to the same rail on the rest of the layout.
 
Gomez... thanks for the quick reply. One thing I should have mentioned... the two tracks on either side of the fuel tanks... have their own feeders running to the bus. I know.. way to many feeders. If I am understanding your suggestion correctly and making it fit to my feeder situation.... could I cut the feeders now attached to the bus. Attach the cut feeders from the track to an on/off switch. And attach the other end of the now cut feeders from the on/off switch to the bus... remembering to install the isolated rail joiners on either end of the rails.
 
PrairieKnight said:
Gomez... thanks for the quick reply. One thing I should have mentioned... the two tracks on either side of the fuel tanks... have their own feeders running to the bus. I know.. way to many feeders. If I am understanding your suggestion correctly and making it fit to my feeder situation.... could I cut the feeders now attached to the bus. Attach the cut feeders from the track to an on/off switch. And attach the other end of the now cut feeders from the on/off switch to the bus... remembering to install the isolated rail joiners on either end of the rails.
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That would work.
 
You only need to cut one of the wires and insert a toggle in series. If the toggle is in the off position, there is no continuity, and the decoders won't be getting any power through them.
 
Thanks Gomez and Selector. Thanks to you I know how to do it. But if I may ask..... does cutting the power to the engine track prolong the life of or prevent any damage (damage might be a little harsh) to the decoders in the my Proto locomotives that at the present time are idling with the sound turned off?
 
PrairieKnight said:
But if I may ask..... does cutting the power to the engine track prolong the life of or prevent any damage (damage might be a little harsh) to the decoders in the my Proto locomotives that at the present time are idling with the sound turned off?
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That is the $25,000 question. One school of thought is that turning them off increases their life simply because they aren't working so much. And yes, they are working while idling. They are sitting there monitoring the DCC signal for their address to see if there is a command to respond to.

The other school of thought is that more damage is done to an electronic component when it is powered on with the initial inrush of electrons than any other time, so it is best to leave them on.

I am guessing in the long run with as seldom as we actually use these toy trains it won't matter. Would be different if this was a public demo layout that was on 8-16 hours a day, every day of the week. My second guess is that some of these schools of thought are from the old fashion pre-digital days of electronics.

Any current EEs out that could enlighten us?
 
Hi I have the NCE PowerCab controller. I idle up to 12 or 13 engines in the yard and industrial sidings, while I run 4 trains on the main loops and one or two trains on the outer "high speed" passenger loops. Limit is 6 in the NCE unit. When all this is going on, I am pulling around 900mA. This is about 1/2 of the rated capacity of the NCE. So, I think you can run your trains with no issues. The PowerCab is short-protected, of course.
 
PrairieKnight said:
Thanks Gomez and Selector. Thanks to you I know how to do it. But if I may ask..... does cutting the power to the engine track prolong the life of or prevent any damage (damage might be a little harsh) to the decoders in the my Proto locomotives that at the present time are idling with the sound turned off?
Click to expand...
I worked in electronics since 1974. The reliability of modern electronic parts (there are exceptions with some Chinese sources) is really good. I still have amplifiers I built in 1972 that work perfectly (they did get new capacitors, as these are "wear parts"). You do not have to worry about cycling the power. As was noted above, the number of cycles is actually very small.
 
GGNInNScale said:
I worked in electronics since 1974. The reliability of modern electronic parts (there are exceptions with some Chinese sources) is really good. I still have amplifiers I built in 1972 that work perfectly (they did get new capacitors, as these are "wear parts"). You do not have to worry about cycling the power. As was noted above, the number of cycles is actually very small.
Click to expand...
Yup, the class of electronics now days is really quite good. If it has AC mains, power cycling is not even in the equation - as the power cycles 60 ( USA and others, 50 most 3rd world countries ) times a second. In the old days, most of the problems existed in the secondary with the filter caps. Those were what is called 'loosely' made with materials to go along with that. Now days, the filter caps MTBF's are upwards of 500K hours. If it is a good design the inrush current to the secondaries is limited to a safety factor and should take 5 time constants to get up to wanted voltage. Those 5 time constants are created by an RC circuit in the secondary so that the R ( resistance ) only allows so much inrush current per unit of time. This should be true with Linear or Switching power supplies. You can have 'infant mortality' failures which happen from product birth to maybe 30days out. Something happened with the IC or active element silicone doping, solder mask, solder and/or some pcb error. Those are hard errors, not design errors persay.
 
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