# subways and computer disks

**URL:** <https://boards.straightdope.com/t/subways-and-computer-disks/173551>\
**Category:** Factual Questions\
**Created:** [May 7, 2003, 12:02am UTC](https://boards.straightdope.com/t/subways-and-computer-disks/173551 "2003-05-07T00:02:46Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![raisinbread](https://avatars.discourse-cdn.com/v4/letter/r/8491ac/32.png) [@raisinbread](https://boards.straightdope.com/u/raisinbread)\
**Post date:** [May 7, 2003, 12:02am UTC](https://boards.straightdope.com/t/subways-and-computer-disks/173551/1 "2003-05-07T00:02:46Z")

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I’m going to be in the NYC area soon and I was reminded of an odd event that always seemed to happen to me.  
I had a web design job and brought along copies of my work on disc, not wanting to drive into the city I would take NJ transit to the PATH and hop an uptown subway.  
When I’d get to the NYC office, the discs would be unreadable. The first time I figured that it was a fluke. The second time I tested the disc on two computers, before getting on the trains, and it worked fine but once I got into the NYC office the disc was unreadable.  
Is there enough electromagnetic radiation in the NYC subways or on trains that it’d completely ruin my discs? It’s not like I was rubbing the things along the third rail or anything bizarre like that. Could it affected the saved games on my gameboy advance cartridges too?

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**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\
**Post date:** [May 7, 2003, 3:35am UTC](https://boards.straightdope.com/t/subways-and-computer-disks/173551/2 "2003-05-07T03:35:00Z")

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Big electromagnetic field?

[http://www1.od.nih.gov/cbthtml/pchwsw.htm](http://www1.od.nih.gov/cbthtml/pchwsw.htm)

> [@](#):
>
> If you place a floppy disk on top of the monitor or near any electrical appliance, the magnetic field can erase or damage the files.

Metal detector?

[http://www.nmclites.edu/infotech/its/how/diskettes.htm](http://www.nmclites.edu/infotech/its/how/diskettes.htm)

> [@](#):
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> Keep your floppy away from devices that produce magnetic fields – like your monitor, speakers and, yes, refrigerator magnets. Floppy disks are not in any danger when X-rayed by airport security. X-rays are not magnetic. (They are electromagnetic energy but then again so are visible light rays.) But do watch out for the metal detectors: most employ a weak magnetic field to find metal.

Cell phone next to floppy in backpack?

> **[Robert McMillen](https://www.youtube.com/user/clickx3)**
>
> Robert McMillen is an IT consultant, college instructor, has an MBA, over 50 technical certifications and is a Microsoft Certified Trainer (MCT).
> 
> Now ranked in the top 1% of all YouTube Channels by SocialBlade!
> 
> "This channel is designed to teach...

> [@](#):
>
> Info constantly disappears from floppies.
> 
> Check to make sure there are no electromagnetic devices near your floppies. A telephone, a hair dryer, or any other household appliance can erase the info on a disk if it’s too close. A safe distance is about 12 inches.