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Did anyone determine root cause of Ken Patterson unattended train operation fire on his basement layout?
He had no real smoke alarms I am told either to avoid triggering when he was smoking in the basement area.
Luckily he had operational fire extinguishers!
He had no breakers other than the one in the digitrax. Which wasn't ment for a long term short. Styrene in both solid plastic and the foam form is highly flammable. When a breaker short cycles and does not have a long term kill until fixed issues accure Those aren't ment to be unattended breakers. Most likely that digitrax breaker kept cycling. As it idid the rail and or wheel set kept heating up. The metal will heat faster than cool. the temp went way up most likely ignitghing the ties and trucks or passenger cars. Also kept heating through the cycling to get so hot as to heat enough down do the road bed and foam. Also possible a metal handrail or break rigging fell off causing a short. Since every thing was running fine moments before, I would say that is the most likely reason.
The biggest thing too keep in mind is the flammability of styrene. and how DCC is a different animal from standard DC. Maybe the whole foam thing isn't a good idea anymore for DCC layouts. Also worth noting that anything can suddenly happen no matter how good everything runs.
I understand he had left a train running on its own while he went upstairs, something you should never do.
The loco ran a switch that was set against it and derailed/jammed itself bridging the gap which caused a red hot short.
Also heard he mounts the track directly to the styrofoam in that area or something like that.
He has cameras aimed at his layout and saw the smoke.
Are there breakers which have a give up and break instead of cycling?
What are alternatives easily sculpted like the foam?
nGuru Train Layouts & Components
The loco ran a switch that was set against it
Rico, I know you know this, but thought some might need it...
When you run wired turnouts protected with a simple light bulb
you can avoid the derailment and likely the fire. Light bulbs still present a significant danger - they still let power flow, b
ut you will have much more time to notice the problem.
Of course, a quality breaker is much preferred over a bulb(s).
nGuru Train Layouts & Components
Are there breakers which have a give up and break instead of cycling?
What are alternatives easily sculpted like the foam?
A quality breaker does not need to rest, they can cycle without danger - it is the cheapy breaker in the command stations that cannot handle constant cycling.
I do the easyScape thing for most landscape where "digging" is needed, and pretty much anywhere I can nowadays.
But foam is great too, though I do not use it where track or wiring are located because of fire concerns. Quite often I assemble a bunch of castings, and then use great stuff foam to reinforce it all.
You know, ass backwards...
Response from Digitrax tech support about Peterson fire and need for additional circuit breaker:
From Engineering:
The system command station/boosters/power managers provide track side circuit protections assuming adequate layout wiring.
We do recommend current protection devices between the DC power supply and Command Station/Booster when the Screw Terminal Power IN connections are used. The current protection device should match the amperage rating of the booster or command station.
The best protection is not to leave your layout for 20 minutes while you go get a cup of coffee or go outside to smoke or whatever Ken went to do.
Tech Support
20 years ago when I was an architectural model maker, we used rigid polyurethane foam for topography. It varied in density from 3 lbs per cubic ft to 25. The dust was very gritty but the foam was fire resistant.
It seems the heat came from the short pulses the command station was trying to apply power. The metal heated more during the pulse than it cooled during the pause.
My DB150 from Digitrax senses the fault, beeps repeatedly, and will cut track power. It keeps sensing, but it will not attempt to return power until it no longer detects the short. This has taken place faultlessly on my layout since I purchased the system back in 2005. I also use an auto tail light bulb for my yard 'district' to protect all the idling locos with sound decoders that are likely parked there.
I don't know what Digitrax system Ken had, but his system's circuit breaker is auto-reset. The system detects a short: kills track power, beeps, reapplies track power. Since the short wasn't cleared (as Ken was not in the room) the short kept happening and got hot enough to ignite either the foam the track was laid on (no cork or other sub/roadbed) or other scenery material. If you watch this video he talks about the fire and how he was mistaken about his initial belief that the cause was his paint-booth, and other thoughts. I don't recall if he talks about how long between the initial short and the flames or not, but it was not instantons i.e. not short than flames.
And as has been brought up on other forums:
For those concerned with the fire issue the lessons learned are:
- Don't leave a train running when you leave the room and/or don't leave the layout powered on
- Don't use auto resetting circuit breakers
- Do have power districts that restrict max current to a reasonable value, not the full (8 amps in Ken's case) output of the DCC system in case of a short
- Do have smoke detectors in the layout room
- Do have a fire extinguisher handy in something does happen
Also mentioned was that foam leaves a black stringy residue that is worse than simple wood smoke residue. The polystyrene in foam will leave "cobwebs" of burnt plastic all over.
I just installed two smoke detectors in the basement. One at the foot of the stairs (Admittedly overdue as the old one had died some time ago), and the second in the train room itself.
Nothing like seeing someone else's tragedy to spark you out of laziness.
And I just purchased 2 portable fire extinguishers!
Yes it’s a bit of a wake-up call for all isn’t it.
I already have an extinguisher in the room but an alarm is forth coming now as well.
I should add I have a strict rule of not leaving trains run without an engineer nearby.
IT is my practice as well....I double check that my power bar is off before I leave the room for any reason. I have forgotten, admittedly, but at least I stop all trains and turn off track power via the throttle, and then confirm that the red LED is not lit on the face of the DB150.
Digitrax tech support does admit that their controllers auto cycle back on after a brief time to see if short is resolved.
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