Large Scale Central

Lighting and track

I run on rail power (DCC, though I think this applies to DC as well), and recently had a booster fail. There was no evidence of burning, such as what might happen with a near lightning strike. And I’ve always left the system connected (though protected in a small shed). With some help from Greg E. on determining which components worked and didn’t, I sent the booster in for repair. I gather that it’ll take around a month to get back.

Boosters are expensive, so I wondered what happened, and if I should be prepared for this to be a recurring thing. I posted my questions on a DCC forum that specializes in my brand of equipment (NCE), and after a lot of ideas thrown around, I received this reply.

Hi Cliff, I’m a fellow garden railroader and I use the same system as you including the Meanwell power supply Greg [Elmassian] recommends. When my system is not in use, I use to just unplug my power supply. The track remained connect to the booster. Along came a thunder storm. Had a rather strong bolt hit down the street about a quarter mile away. I have about 300 feet of track, nice antenna. The EMI pulse damaged my booster and my NCE wireless system. I had to send them to NCE for repair. I never saw any physical damage. I now make sure I disconnect the track from the booster when not in use. Not saying this is what happened to your system but it is a possibility. Hope you get back up and running soon. Good luck. --Steve

According to Steve, track can act as an “antenna” that gathers static electricity from a lightning strike, conveying enough of a pulse to damage any connected electronics. This makes sense; and you can bet I’ll be disconnecting from now on.

I suppose this applies to any electronic gear, though maybe DC throttles have less sensitive components?

Anyway, I’d like to hear any comments y’all might have along these lines, and whether you always disconnect when not operating.



I am wondering if “gather static electricity” is the correct phenomenon here. Maybe he meant the lightning imparts a static charge on the tracks? If that were the case, would your amplifier be the path through which it discharged? It would also suggest being the first person to touch the tracks after the strike could be a “shocking experience!”

I wonder if your track simply acted as a as a conductor. Its large footprint on the ground could have picked up and directed the electricity from a nearby strike to / through anything attached to the tracks. We experienced something similar growing up, when lightning strikes would cause a surge currents in the TV cable and blow the TV’s tubes.

Interesting subject, because, whatever the cause, it presents a safety of person and safety of equipment issue!

Oh, and yes, we unplug everything. Our little controllers are not weather hardened, so we have no choice!


Hi Cliff, before there is too much speculation about my response to your post I should add more details. I believe that due to the near by lightning strike a EMP or electromagnetic pulse was generated. This was not a direct hit. I believe the receiving end of this disturbance was my booster through my track (lack of the proper term I called it an antenna). I believe there were two possible routes the pulse took to get to my booster. One was the track itself. Two my outdoor NCE RB02 wireless receiver powered by a wall wart (DC power supply) plugged into and outside AC outlet. The booster’s power supply itself was unplug from household AC. Now since both my RB02 wireless and my booster were damage, but not my command station, I am guessing the booster received it’s damage through the track and the RB02 was damaged through the outside AC outlet and wall wart. The wall wart was also damaged. I hope I both cleared up some confusion (which apologize for) and made outside DCC users aware that all connections from the outside world to out sensitive and expensive electronics should be removed when not in use.



Would a knife switch on the leads to the track work to disconnect ?

One needs to think about how lightning occurs and reaches the ground. A cloud high in the sky gets a charge and discharges down to earth and wants to taqke the path of least resistance, and that is metal. Now remember how far this lightning has traveled just to reach earth. In my opinion a switch would not deter this strike as it has mostlikely already traveled over a mile to reach you. Best protection is what tall buildings in cities do to their buildings. They add a metal spike to the top most parts of their buildings and use a very large cable to ‘ground’ the spikes to the ground (possibly water mains).

In my State swimming pools are required to have a #8 wire added to all metal parts and ties to the water pipe coming in to the house. Telephone equipment had a ’ 4 foot ground rod’ pounded into the ground. Cable company added a ground to my water pipe as did the solar company plus the solar company tied the roof panel to a ground rod they installed and picked up my pool ground wire which is connected to my water pipe.

Will this be 100 per cent protection?? Probably not, but is probably the best protection that one could have.

Thanks Dan and Eric for your comments.

Steve, thanks for chiming in. I think the idea of the track acting as means of gathering electricity in the air due to lightning (whatever the proper terminology might be) just makes sense, and your post was the first I’d heard of that potentiality.

I use #10 wire for the DCC track wiring, all connected to the control stack with dual banana plugs – another thing I learned from Greg E. Very easy to disconnect, and now I will leave it so as the default.

Dan Pierce said: (snip)

One needs to think about how lightning occurs and reaches the ground. A cloud high in the sky gets a charge and discharges down to earth and wants to taqke the path of least resistance, and that is metal.

Don’t know that this part matters, but…

Does lightning strike from the sky down, or the ground up?
The answer is both. Cloud-to-ground lightning comes from the sky down, but the part you see comes from the ground up. A typical cloud-to-ground flash lowers a path of negative electricity (that we cannot see) towards the ground in a series of spurts. Objects on the ground generally have a positive charge under a typical thunderstorm. (The charge that builds up in a small area of the Earth’s surface and the objects on it is determined by the net charge above it since the Earth’s surface is relatively conductive and can move charge in response to the thunderstorm.) Since opposites attract, an upward streamer is sent out from the object about to be struck. When these two paths meet, a return stroke zips back up to the sky. It is the return stroke that produces the visible flash, but it all happens so fast - in a few thousandths of a second - so the human eye doesn’t see the actual formation of the stroke. Natural lightning can also trigger upward discharges from tall towers, like broadcast antennas.

Never had trouble with the layout but did have 1,000 feet of chain ink fence electrified by a lightening bolt. Melted a spot on the gate. Layout wasn’t built at that time. We ground everything.

Never had trouble with the layout but did have 1,000 feet of chain ink fence electrified by a lightening bolt. Melted a spot on the gate. Layout wasn’t built at that time. We ground everything.

Great to see you again Doug, thanks for posting.

Which brings up a question. Do you, or anyone else, take steps to ground the track? For rail powered layouts, I’d think that would short the system…

Dan, what I am referring to is a radiated pulse of energy, not a direct hit. Not much you could do about a direct hit other than trying to redirect it to ground. This lightning electromagnetic pulse (LEMP) is created from the lightning strike. The pulse does not have the same amount of energy as the bolt itself. A switch might work but I just prefer to just unplug the track at my boosters input. Here is a link about electromagnetic pulses. I am obviously referring to the natural lightning type not the man made nuclear type.


Back in the day, Tom Ruddel did an extensive article over at MLS on lightning damage he incurred and the steps he took to reduce his risk. When I powered my layout (DC w/wireless control) I followed his lead and installed a physical disconnect jumper made from 3 feet of #12 wire and 20 amp connectors in outdoor boxes. This is located outdoors where the wire entered the house. I would remove the jumper when not running trains.

I cut the cord quite a few years ago, but have since used the existing wire for constant 12V to drive lighting circuits. Since the point of lighting is to be able to see it from inside the house I no longer disconnect the jumper except when severe storms are forecast (if I remember).

To my knowledge, I have never incurred any lightning damage to my power system(s), nor any of the electronics in the house. We have had several close calls, but never a direct hit within 500 yards.

Jon Radder said:

Back in the day

In the hood?


Now back to the topic at hand.