[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR201.23]

[Page 74]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 201--NOISE EMISSION STANDARDS FOR TRANSPORTATION EQUIPMENT; INTERSTATE 
RAIL CARRIERS--Table of Contents
 
                     Subpart C--Measurement Criteria
 
Sec. 201.23  Test site, weather conditions and background noise criteria for 
measurement at a 30 meter (100 feet) distance of the noise from locomotive and 
rail 
          car operations and locomotive load cell test stands.

    (a) The standard test site shall be such that the locomotive or 
train radiates sound into a free field over the ground plane. This 
condition may be considered fulfilled if the test site consists of an 
open space free of large, sound reflecting objects, such as barriers, 
hills, signboards, parked vehicles, locomotives or rail cars on adjacent 
tracks, bridges or buildings within the boundaries described by Figure 
1, as well as conforms to the other requirements of this Sec. 201.23.
    (b) Within the complete test site, the top of at least one rail upon 
which the locomotive or train is located shall be visible (line of 
sight) from a position 1.2 meters (4 feet) above the ground at the 
microphone location, except as provided in paragraph (c) of this 
section.
    (c) Ground cover such as vegetation, fenceposts, small trees, 
telephone poles, etc., shall be limited within the area in the test site 
between the vehicle under test and the measuring microphone such that 80 
percent of the top of at least one rail along the entire test section of 
track be visible from a position 1.2 meters (4 feet) above the ground at 
the microphone location; except that no single obstruction shall account 
for more than 5 percent of the total allowable obstruction.
    (d) The ground elevation at the microphone location shall be within 
plus 1.5 meters (5 feet) or minus 3.0 meters (10 feet) of the elevation 
of the top of the rail at the location in-line with the microphone.
    (e) Within the test site, the track shall exhibit less than a 2 
degree curve or a radius of curvature greater than 873 meters (2,865 
feet). This paragraph shall not apply during a stationary test. The 
track shall be tie and ballast, free of special track work and bridges 
or trestles.
    (f) Measurements shall not be made during precipitation.
    (g) The maximum A-weighted fast response sound level observed at the 
test site immediately before and after the test shall be at least 10 
dB(A) below the level measured during the test. For the locomotive and 
rail car pass-by tests this requirement applies before and after the 
train containing the rolling stock to be tested has passed. This 
background sound level measurement shall include the contribution from 
the operation of the load cell, if any, including load cell contribution 
during test.
    (h) Noise measurements may only be made if the measured wind 
velocity is 19.3 km/hr (12 mph) or less. Gust wind measurements of up to 
33.2 km/hr (20 mph) are allowed.