News

De nye IC4-tog er mere støjende for passagerne end IC3-toget og de københavnske S-tog

DELTA-Share_960x240_ic4tog

DELTA foretog i oktober 2013 støjmålinger i passagerafsnittene i henholdsvis et københavnsk S-tog (idriftsat fra 1996), et IC3-tog (idriftsat fra 1990) og et IC4-tog (idriftsat fra 2007).

Målingerne kom i stand, fordi en journalist fra fagbladet Ingeniøren på en tur i med IC4-toget i efteråret 2011 havde været udsat for en meget støjende oplevelse i et IC4-tog og allerede den gang tog kontakt til DELTA. Målingerne måtte udskydes, da togene på grund af bremseproblemer var ude af drift i en længere periode.

Støjmålingerne, der blev foretaget den 7. oktober 2013 i de nævnte togtyper, viste, at det A-vægtede lydtrykniveau ved hastigheden 140 km/t var 75 dB(A) i IC4-toget og 65 dB(A) i IC3-toget. En forskel på 10 dB vil i gennemsnit opleves som en fordobling af støjniveauet af et normalthørende menneske.

I en artikel, der blev bragt i Ingeniøren den 18. oktober 2013 om DELTA’s støjmålinger, udtalte tillidsmand for togpersonalet ved DSB Niels Henrik Nielsen:

”Togpersonalet i IC4 siger samstemmende, at lydniveauet er meget generende og højere end i IC3-tog. En speciel tone i IC4-toget er meget generende. Selvom DSB har arbejdet på at nedbringe lydniveauet, er problemet ikke løst tilfredsstillende endnu,” siger han.

Under målingerne den 7. oktober 2013 kørte IC4-toget kun med en topfart på 140 km/t i stedet for den normale topfart på 180 km/t som følge af mulige bremseproblemer på grund af nedfaldende blade. Støjniveauet er formodentlig et par dB højere ved 180 km/t. Ved målinger i det gamle IC3-tog ved 180 km/t var støjniveauet 66 dB(A), altså stadig betydeligt under støjniveauet i IC4-toget ved 140 km/t.

Målingerne viste også, at der er betydelig forskel i støjniveauerne i IC4-toget. I lavtgulvsafsnittet, der er beregnet til fx kørestolsbrugere og cykler, blev der målt et støjniveau på 61 dB(A) ved 140 km/t.

Fakta

I mange sammenhænge A-vægter man den målte støj. Derved vil lydtrykmåleren i store træk have samme følsomhed overfor lydens frekvenser som det menneskelige øre, fx hører vi dårligere i det lavfrekvente område (”baslyde”) end i mellemfrekvensområdet 500-5000 Hz. Lydtrykmåleren vil med A-filteret indkoblet efterligne ørets følsomhed.

Som håndregel skal det A-vægtede støjniveau øges med 10 dB for at vi subjektivt oplever lydniveauet som fordoblet. De fleste vil kunne høre en ændring på 3 dB, de færreste kan registrere en ændring på 1 dB.


ENGLISH VERSION


DELTA-Share_960x240_ic4tog

Passengers exposed to much more noise inside the modern IC4 trains compared to regional S-trains operating in Copenhagen or IC3 trains

In October 2013, DELTA measured noise levels in passenger sections in an S-train (operating since 1996), an IC3 train (operating since 1990) and an IC4 train (operating since 2007).

The measurements came about because a journalist working for engineering specialist magazine ‘Ingeniøren’ had taken a very noisy journey on an IC4 train in the autumn of 2011 and very quickly contacted DELTA. The measurements had to be postponed because brake problems meant the new trains were taken out of operation for a long period.

Noise measurements were finally taken on 7 October 2013 in the different types of train and the A-weighted sound level at a speed of 140 km/h was 75 dB(A) in the IC4 train and 65 dB(A) in the IC3 train. In general, a difference of 10 dB is the equivalent of a doubling in the level of noise perceived by a person with normal hearing.

In an article about DELTA’s noise measurements published in ‘Ingeniøren’ on 18 October 2014, trade union representative for staff working in DSB (the Danish national railways), Niels Henrik Nielsen said:

“All of the IC4 staff agree that in general, the noise level is much higher than in IC3 trains. The IC4 train has a particular tone that is very irritating. Even though DSB has worked to reduce the noise level, the problem has still not been satisfactory resolved.”

When the measurements were taken on 7 October 2013, the IC4 train only operated with a top speed of 140 km/h rather than its normal top speed of 180 km/h because of potential brake problems due to falling leaves on the line. At 180 km/h, the level of noise is presumably a couple of dBs higher. The level of noise for the old IC3 train was measured as 66 dB(A) while it operated at 180 km/h – significantly quieter than the IC4 train operating at only 140 km/h.

The measurements also showed that there are significant differences in the level of noise depending where you are inside the IC4 train. In the low-level floor area, designed for use for passengers with bicycles and wheelchairs, the noise level was measured as 61 dB(A) at 140 km/h.

Facts

The measured noise is A-weighted in many situations. Broadly speaking, this means that the sound level meters have the same sensitivity to the sound’s frequency as the human ear. For example, we hear worse in the low frequency range (‘base sound’) compared to the medium frequency range 500–5,000 Hz. The sound level meter will have an A-filter connected, which mimics the ear’s sensitivity.

As a rule of thumb, an A-weighted sound level that increases by 10 dB is experienced as a doubling in volume for an average listener. The majority of people can register a change of 3 dB in the sound level, and only a minority of people can register a change of 1 dB.

Tags:

This is a unique website which will require a more modern browser to work! Please upgrade today!