[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: 40CFR201.26]

[Page 77-78]
 
                   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. 201.26  Procedures for the measurement on receiving property of 
retarder and car coupling noise.

    (a) Retarders--(1) Microphone. The microphone must be located on the 
receiving property and positioned at a height between 1.2 and 1.5 meters 
(4 to 5 feet) above the ground. The microphone must be positioned with 
respect to the equipment in accordance with the manufacturers' 
recommendations for Type 1 or 2 performance as appropriate. No person 
may stand between the microphone and the equipment being measured or be 
otherwise positioned relative to the microphone at variance with the 
manufacturers' recommendations for Type 1 or 2 performance as 
appropriate.
    (2) Data. The maximum A-weighted sound levels (FAST) for every 
retarder sound observed during the measurement period must be read from 
the indicator and recorded. At least 30 consecutive retarder sounds must 
be measured. The measurement period must be at least 60 minutes and not 
more than 240 minutes.
    (3) Adjusted average maximum A-weighted sound level. The energy 
average level for the measured retarder sounds must be calculated to 
determine the value of the average maximum A-weighted sound level 
(Lave max). This value is then adjusted by adding the 
adjustment (C) from Table 2 appropriate to the number of measurements 
divided by the duration of the measurement period (n/T), to obtain the 
adjusted average maximum A-weighted sound level 
(Ladj ave max) for retarders.
    (b) Car coupling impact--(1) Microphone. The microphone must be 
located on the receiving property and at a distance of at least 30 
meters (100 feet) from the centerline of the nearest track on which car 
coupling occurs and its sound is measured (that is, either the 
microphone is located 30 meters (100 feet) from the nearest track on 
which couplings occur, or all sounds resulting from car coupling impacts 
that occur on tracks with centerlines located less than 30 meters (100 
feet) from the microphone are disregarded). The microphone shall be 
positioned at a height between 1.2 and 1.5 meters (4 and 5 feet) above 
the ground, and it must be positioned with respect to the equipment in 
accordance with the manufacturers' recommendations for Type 1 or 2 
performance as appropriate. No person may stand between the microphone 
and the equipment being measured or be otherwise positioned relative to 
the microphone at variance with the manufacturers' recommendations for 
Type 1 or 2 performance as appropriate.
    (2) Data. The maximum A-weighted sound levels (FAST) for every car 
coupling impact sound observed during the measurement period must be 
read from the indicator and recorded. At least 30 consecutive car 
coupling impact sounds must be measured. The measurement period must be 
at least 60 minutes and not more than 240 minutes, and must be reported.

[[Page 78]]



Table 2--Adjustment to Lave max To Obtain Ladj ave max for Retarders and
                        Car Coupling Impacts \1\
 [n/T=number of measurements/measurement duration (min) C=Adjustment in
                                   dB]
0.111 to 0.141..................................................      -9
0.142 to 0.178..................................................      -8
0.179 to 0.224..................................................      -7
0.225 to 0.282..................................................      -6
0.283 to 0.355..................................................      -5
0.356 to 0.447..................................................      -4
0.448 to 0.562..................................................      -3
0.563 to 0.708..................................................      -2
0.709 to 0.891..................................................      -1
0.892 to 1.122..................................................       0
1.123 to 1.413..................................................      +1
1.414 to 1.778..................................................      +2
1.779 to 2.239..................................................      +3
2.240 to 2.818..................................................      +4
2.819 to 3.548..................................................      +5
3.549 to 4.467..................................................      +6

\1\ Ladj ave max=Lave max +C in dB.
Values in Table 2 were calculated from [C=10 log n/T] with intervals
  selected to round off values to the nearest whole decibel. The table
  may be extended or interpolated to finer interval gradations by using
  this defining equation.

    (3) Adjusted average maximum A-weighted sound level. The energy 
average level for the measured car coupling sounds is calculated to 
determine the average maximum sound level (Lave max). It is 
then adjusted by adding the adjustment (C) from Table 2 appropriate to 
the number of measurements divided by the duration of the measurement 
period (n/T), to obtain the adjusted average maximum A-weighted sound 
level (Ladj ave max) for car coupling impacts.