Western Railroad Discussion > AC locomotive question

Does anyone know if there are any hazards with AC traction locomotives in regard to the electrical systems when fighting a fire on board these locomotives?

According to my BN SD70MAC operating manual, the SD70MAC has input filter capacitors for each of the traction inverters. The capacitors filter the main generator output which is the DC link voltage, before it is applied to the two inverters. When the locomotive is shutdown these capacitors could retain this high voltage for a long period of time causing a severe safety hazard for operating and maintenance personnel. The DC link voltage is present in all equipment connected to the output of the main generator.

There is a procedure to "Cut in" the inverters to the dynamic brake grids to de-power them but this has to be done thru the EM2000 diagnostic display screen. If the invert or cannot be cut in to the d/b grid for discharge, it can retain power for up to 40 minutes.

My question is, what danger to firefighting efforts is it on the AC powered locomotives if they are involved in a fire where the electrical systems cannot be de-powered? With six invertors are the GE locomotives more dangerous when fighting a onboard fire? And do you have to wait for the electrical system to depower before extinguishing a onboard fire?

Regards
Q-GP30

not real sure about specifics but I know if you throw a steady stream of water on a capacitor you are going to get knocked on your butt IF you live through it.

On the UP, we're not allowed to use fire extinguishers, so you just shut the unit down, get off, and let it burn.-BMT

SD70MAC manual:

As a safety measure, the DC Link switchgear has been designed to automatically short the invertors and discharge the storage elements if:
a. The unit has been in isolate for more than 20 seconds. Or,
b. The engine shuts down.
If either of these situations occur the switchgear will first move to the centered position then to the shorted position. When in the shorted position a screen in the ICE computer will show the voltage stored in each invertor to show if the system has been discharged.

Of course if the unit is on fire or wrecked ... who knows what parts of this have worked and which parts haven't.

Just to make certain, there are hi voltage discharge wands located in the hi voltage cabinets in the cab.

Thanks Al and all,
Was talking to the Asst. Cheif of the Hannibal MO FD the other day and this question came up. He assumed you would just foam the heck out of it if it was a major fire, he wondered about the electrical danger.

Regards
Q-GP30

I wonder if, as an OHS & W issue, has the manufacturer held training sessions for the rescue and clearup personnel who are usually the first personnel at a derailment site, etc.

Would it possibly mean that all AC locomotives have to be readily identifiable to rescue personnel as a potential electric shock hazard?

Mike

UPNW2-1083 Wrote:
-------------------------------------------------------
> On the UP, we're not allowed to use fire
> extinguishers, so you just shut the unit down, get
> off, and let it burn.-BMT


On CSX we have extinguishers with powder in them.


Not to offend anyone but if one of CSX's units are on fire, I'm going to grab my grips, get off the train and let that mother$#%^er cook. They don't pay me enough to risk getting burned up to fight fires, only to fire me later for not holding the extinguisher the right way. Just my opinion!

Surely not shorted directly. Probably discharged via resistors.