April 3, 2017

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There was a time in the not to distant past when I would lay in bed early on a Sunday morning at home in Park Hill and listen for the roar of African lions. The sound carried all the way from the Denver Zoo, just over a mile away. What exactly prompted them to roar is unclear to me, but no question, a lion’s roar resonates deeply in your genetic memory and serves as quite the wake up call.

Those roars are just a memory since the ‘new’ A-Train to DIA opened last April 22.

But there’s something wrong with the crossing gates that are supposed to come down and prevent vehicles from getting in the way of trains. They don’t always work. All vehicles are supposed to be blocked at least 20 seconds before a train approaches. None of the news reports explain why similar gates everywhere else in the country (or in the world) can do this and ours do not. As a result each crossing must be ‘manned’ by a live person and each train must blow its warning horn before each street is crossed. [1] The new DIA train runs day and night, blowing its 120 decibel horn at every intersection along the way, between DIA and Union Station down town.[2] The sound of a 120 decibel horn carries far. A significant segment of Denver is aware of each passing train.  It’s been just short of a year.

It’s not just the lion roars that are gone. Quiet sunrise walks in City Park are also a memory. It’s like the good old days when the airport was in Stapleton. Sure I suppose if one lives with ear buds permanently attached, perhaps you don’t notice the train. I guess I’m old fashioned. I still like to be aware of the world around me.

The Renaissance Hotel over on Quebec Street now offers guests white noise machines and ear-plugs in an attempt to drown out the noise from the train. Complaints have come in that people “…can hear the train at night from four miles away in Denver’s Hilltop neighborhood.”[3] Where we live in Park Hill is closer and that train even louder.

This train business has prompted me to read research about noise pollution.

Back in 2002, Lercher et al reported that ambient background noise was inversely associated with the mental health of children. Two groups of Austrian children (n=1280; n=123) in primary school (age 8-11) were studied. Exposure to noise at home was linked with two indices of mental health (self reported by the child and ratings by the classroom. Noise exposure was significantly associated in both groups of children with classroom adjustment ratings. The children’s self reported mental health was also significantly linked to ambient noise. [4]

A 2004 review by Ising and Kruppa covered research published from the prior quarter century on the effects of noise pollution and reported that “…. according to the Environmental Expert Council, these studies show a consistent trend towards an increased cardiovascular risk if the daytime immission level exceeds 65 dB(A).” [5]

Manikandan et al reported in 2006 that rats exposed to chronic noise increased oxidative damage to dendrites and neurons, basically noise caused brain damage. [6]

Attention of city planner has focused on noise from old pre-existing infrastructure, highways and the like, built before we knew better. It’s generally assumed new projects will be designed and built taking the harmful effects of noise into consideration. No one seems to have considered the noise the A-Train would bring to Denver. Of course who would have predicted that the art of building working railroad crossing gates would prove so challenging. This reminds me of that original automated luggage system at DIA that ended up sold as scrap metal when it proved impossible to operate.

“Research needs to measure population-wide health effects of involuntary long-term exposure to ambient noise. Further study of the range and severity of co-morbidities will help refine the thresholds used to protect health.”[7]

For all of our focus on improving student test scores by hiring more teachers to create smaller classrooms and experimenting with core curriculums, the effect of noise on learning is often overlooked. Ronse and Wang reported in a 2013 paper

They measured background noise levels in 67 elementary school classrooms in Nebraska. Sound intensity was correlated to academic test performance. They suggested that background noise “… levels should be less than 45 dBA”. [8]

It turns out that there is an International Commission on Biological Effects of Noise (ICBEN). In 2012 they made an interesting and rather disturbing announcement; there is an “additive and synergetic effects of ambient stressors”. The effects of other stressors such as pesticides and chemical pollutants add on to the toxicity of noise. [9] Recall that noise appears to cause oxidative damage to the brain. Other stressors that do the same add to or are synergistic with noise. Thus while noise may seem to be a relatively small threat, it amplifies the other stressors affected our biology.

We know and expect that living in Denver is noisier and dirtier than living in a less urban environment, and it’s becoming apparent that the combined stressors of noise and pollution are not healthy. The potentially synergistic effects may explain why, “Epidemiological studies have associated growing up and living in cities with a considerably higher risk for schizophrenia.”[10]

The Eastbound morning train arrives at 40th and Colorado at 3:24 am each weekday morning. I don’t sit up to look at the bedside clock though until it arrives at Central Park station at 3:27. In the three minutes it takes to travel between those stations, the train crosses Quebec, Monaco, Holly and Dahlia blowing its horn for each crossing. In theory it’s more than an hour until the 4:34 am arrival of the first westbound train at Central Park station. Often I don’t bother trying to go back to sleep. [

While the train is loud it feels that Denver’s press has been silent on this issue. Gene Amole would never have let this slip by. Mike Litwin would have had me laughing over my breakfast with his outrage on this lunacy. Magnets would hold Ed Stein’s train cartoons on our refrigerator making me laugh. The Rocky Mountain News is gone and no one as intelligent, sharp or caring has come along to replace their columnists. We have lost something valuable in our public life; it’s not just the silence but also the voices of thoughtful people, willing to speak up and criticize our city government and help steer public decisions toward a better future. Back in that time when news was real.

Just saying.

Perhaps writing these thoughts down will allow me to fall back asleep while listening to the train whistles. I would rather listen for the lions at dawn than that 3:45 train.



  1. http://www.denverpost.com/2016/10/21/rtd-a-line-design-delays-lightning-issues/
  1. http://www.9news.com/travel/residents-near-a-line-complain-about-loud-train-horns/153004550
  2. http://denver.cbslocal.com/2016/10/06/residents-hotel-guests-suffer-sleepless-nights-thanks-to-dia-train/
  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1740306/pdf/v059p00380.pdf
  1. Lercher P1, Evans GW, Meis M, Kofler WW. Ambient neighbourhood noise and children’s mental health. Occup Environ Med. 2002 Jun;59(6):380-6.
  1. Ising H, Kruppa B. Health effects caused by noise: evidence in the literature from the past 25 years. Noise Health. 2004 Jan-Mar;6(22):5-13.
  2. http://www.noiseandhealth.org/article.asp?issn=1463-1741&year=2004&volume=6&issue=22&spage=5&epage=13&aulast=Ising
  1. Manikandan S, Padma MK, Srikumar R, Jeya Parthasarathy N, Muthuvel A, Sheela Devi R. Effects of chronic noise stress on spatial memory of rats in relation to neuronal dendritic alteration and free radical-imbalance in hippocampus and medial prefrontal cortex. Neurosci Lett. 2006 May 15;399(1-2):17-22.
  1. Moudon AV. Real noise from the urban environment: how ambient community noise affects health and what can be done about it. Am J Prev Med. 2009 Aug;37(2):167-71. doi: 10.1016/j.amepre.2009.03.019.
  1. Ronsse LM, Wang LM. Relationships between unoccupied classroom acoustical conditions and elementary student achievement measured in eastern Nebraska.J Acoust Soc Am. 2013 Mar;133(3):1480-95. doi: 10.1121/1.4789356.
  2. Leroux T, Klaeboe R. Combined exposures: an update from the International Commission on Biological Effects of Noise. Noise Health. 2012 Nov-Dec;14(61):313-4. doi: 10.4103/1463-1741.104900.
  3. Gruebner O, Rapp MA, Adli M, Kluge U, Galea S, Heinz A. Cities and Mental Health. Dtsch Arztebl Int. 2017 Feb 24;114(8):121-127.