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Reversing trains of old were mistaken for Hoarse Fredrik

Shortly after 4 o'clock on Wednesday morning there was suddenly a strong signal over central Stockholm. Christer Wälivaara living in Birkastan woke up directly

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Reversing trains of old were mistaken for Hoarse Fredrik

Shortly after 4 o'clock on Wednesday morning there was suddenly a strong signal over central Stockholm. Christer Wälivaara living in Birkastan woke up directly out of the sound.

" I woke up with a jolt. It was almost exactly 4. The first thing I did was that I opened the windows and checked out. Several others had done the same thing, " he says.

it was about the repeated signals with pauses, to its structure resembled the sound of a VMA-alarm – an ”important notice to the public”. DN has also received information from the reader that the night signals bar high similarity with the a VMA signal.

" There were several signals. Exactly as Hoarse Fredrik, " says Christer Wälivaara.

During the morning session went the state's site Krisinformation.look on Twitter with the information that there was no VMA signal. Instead, it was a reversing of the trains in central Stockholm that caused the strong sound.

Peter Enell, kommunpolis on the island of Kungsholmen, tells DN to a familiar to him, observed how a train was backed very slowly.

They woke up in the night. It sounded like the Hoarse Fredrik fixed with longer intervals. They said that it must have been someone who drove into the wrong track. They saw that they tried to back back train, " says Peter Enell.

, a systems architect at the Authority for the protection and preparedness, MSB, tells us that the signal from the train's horn, which creates the sound, are liable to be confused with the signal from the Hoarse Fredrik's typhoons.

– It is the same brand. I think that it is Kockums typhoons that trains use. But it's not so much we can do about that they are using them.

Several things are different, however, VMA-alarm from the tågtutor, even if they happen to be made by the same manufacturer, " says Håkan Marcusson.

– If there is a VMA so it is not really a horn, but several tutor. And they move not of themselves, that a train makes. It is also not exactly the same frequency.

It was not Hoarse Fredrik sounded the night of Wednesday in Stockholm without a reversing train. Photo: Johan Nilsson/TT

located at around 270 hertz, and thus will differ from a tågsignal, " says Håkan Marcusson on. At the same time, he has the understanding that people generally do not directly hear the difference on frequency.

– A VMA-signal sound in seven seconds and has a gap of 14 seconds after that. But it is very unfortunate that slopes with a train and the horn sounds like Hoarse Fredrik, " he says.

Since several years back keeps the Hoarse Fredrik-tutorna around in Sweden to be replaced. Instead of a kompressordriven the typhoon, " says Håkan Marcusson, the signal will be produced electronically. So far, about 1,500 tutor is replaced. The work progresses with a pace of about 300 a year. In total, there are approximately 4,500 Hoarse Fredrik-tutor in Sweden.

"It is, therefore, a ten-year period before the remaining also are replaced," says Håkan Marcusson.

had they been able to vary the signal so that, in future, it can't be confused with any other signals – if it would be in the news.

Wednesday's event is not unique. Just over a year ago, late on the evening of the 1 January 2018, there was also a sound in the centre of Stockholm, which many interpreted as a flyglarm. Even then it turned out that the cause was just a reversing train.

On 9 July 2017, occurred another event which received a lot of attention. At exactly 22 began Hoarse Frederick sound over the whole of Stockholm county. Then it turned out finally that it was a mistake in connection with a test of the system, when a signal happened to be sent in the way.

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