Question about Electric Trains -;)

When an electric train like, say, one of the old class 303s, was sitting at the platform....

What was it that caused the all-pervaiding 'hum' noise you could hear when everything else about the train was quiet. Something to do with the 'electrics' I daresay. But WHICH part(s). What was the bit called that produced the 'hum'? And, perhaps more importantly, WHY did it 'hum'?

Daft questions maybe, but I've really been wanting to know the answers for years and years... I'm not technical...

Can anyone help? Much obliged if so.

Jim

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Reply to
Jim Donald
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Wrong group mate, try uk.railway, this is about MODEL railways!

Anyway to aswer your question, it would probably be the transformer making the humming noise.

Regards David

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Reply to
DJO

Or air compressors?

Reply to
MartinS

Possibly, but they wouldn't be going continuously, as the original poster seemed to imply.

If it is the transformers, it would be the 50Hz AC making the humming noise, which would be continuous while its pantograph was connected to the juice. Not that I've heard the air compressors on a 303 so they might hum! Djo

Reply to
DJO

Yes defiantly the transformer, used to step down the 25000 volt AV supply to a more useable 750 volts or thereabouts. Then there would probably be some sort of cooling fan running too. Don't know that much about overhead supplied stock.

Hope this helps.

Reply to
Mike

The compressors on 303's did anything but hum!

Alan

Don't reply to this e-mail address - messages will be deleted unread. To reply to me take away the news and substitute alanc

Reply to
Alan Norris

I've wondered about the noises of the old 303's for years as well, but the sound that really mystified me was the "buhbuhbuhbuhbuhbuhbuhbuh" noise that would suddenly break out while stationary. Anyone know what that was?

Cat.

Reply to
The Stainless Steel Cat

=>I've wondered about the noises of the old 303's for years as well, but the =>sound that really mystified me was the "buhbuhbuhbuhbuhbuhbuhbuh" noise =>that would suddenly break out while stationary. Anyone know what that was? =>

=>Cat.

Air pumps, to build up the pressure (or vacuum, depending) in the brake system.

The hums arise both from the on board transformers, and the cooling fans.

Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

Reply to
Wolf Kirchmeir

If it's right beneath you on one of the older trains and a bit dodgy it really hammers. Enough to give you a headache and make your feet numb if you're standing up.

Reply to
Mark W

Cooling fans.

Reply to
Christopher A. Lee

Unless the track's on DCC, in which case the loco is probably not fitted with a decoder...

Guy === May contain traces of irony. Contents liable to settle after posting.

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Reply to
Just zis Guy, you know?

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