Originally Posted by Novacek
I will readily admit that true late-night service may not be economically viable (though I'm not sure this is a datapoint that proves it).
I'm also not sure what noise regulations Capmetro operates under. When they implemented the commuter rail, those freight runs shifted later into the night, and those seem much louder to me (and go on for much longer) than the commuter trains (disclaimer, I live a few blocks over from the tracks).
The freight trains pre-existed commuter rail and are not considered an increase in services. Noise regulations only apply to new services, like commuter rail.
A little background on noise.
Illinois DOT web site on noise abatements.
For different land uses, there are different noise criteria for impacts.
NAC Leq(h), dBA* = Description of Land Use
57 (Exterior) = Lands on which serenity and quiet are of extraordinary significance and serve an important public need and where the perservation of those qualities is essential if the area is to continue to serve its intended purpose.
67 (Exterior) = Picnic areas, recreation areas, playgrounds, active sports areas, parks, residences
, motels, hotels, schools, churches, libraries, and hospitals.
72 (Exterior) = Developed lands, properties, or activities not included in the other categories.
---- = Undeveloped Lands.
52 (Interior) = Residences
, motels, hotels, public meeting rooms, schools, churches, libraries, hospitals, and auditoriums.
A traffic noise impact occurs when noise levels approach, meet or exceed the Noise Abatement Criteria (NAC) warranting a noise abatement analysis.
Illinois Noise Abatement Goals
Noise impacts trigger a noise abatement evaluation. The noise abatement design must meet IDOTs feasible and reasonable criteria. The noise abatement option is determined to be feasible if it achieves at least an 8-dBA traffic noise reduction. A noise abatement option must also be economically reasonable. This means that the noise abatement design does not cost more than $24,000 per benefited receptor. For example, a noise wall benefiting 10 residences at a cost of $240,000 is considered economically reasonable.
Applying this to CapMetro examples....
Train vehicle noise sources:
• Diesel exhaust
• Cooling fans
• Wheel/rail contact
• Horns (primary source of noise) required to be a minimum of 110 db by law.
Note: Horns must be blown at every intersection, usually in the following pattern: 2 long blasts, 1 short blip, and another long blast.
Stadler GTW Lmax (dBA) at 50 feet
70.9 = Stationary, all engines idle
78.1 = 50 mph pass-by forward in mid-throttle
Typical Diesel Locomotive Lmax (dBA) at 50 feet
80 = Stationary, all engines idle
88 = 50 mph pass-by forward in mid-throttle
Note: Choosing a DMU vs traditional locomotive and trailers saves around 10 dbA. Which means DMUs are twice as quiet.
That's the reason why so many new passenger train lines seriously look at implementing quiet zones. Eliminating the need to blow the horn at intersections eliminates most of the noise receptors requiring abatements.
For example in Fort Worth for their TexRail project, according to their DEIS, approximately 70 percent of the noise impacts are due to the sounding of train horns at the numerous at-grade crossings along the alignment and the remaining impacts are due to the train operation.
Residential impacts without mitigation = 1,039
Residential impacts with quiet zones = 274
Residential impacts with quiet zones and 2.65 miles of barriers = 119
Residential impacts eligible for further mitigation (house modifications) = 3
Note: A linear mile of sound barrier costs $1.5 million.
If they decided to no build, no mitigation would be required for the existing freight trains.