联邦法规要求对铁路机车喇叭发出的声音进行测试。 本标准规定了一种替代方法，以符合 无法在没有障碍物的室外空间进行测试的大都市地区。这个 本程序产生的数据与本程序产生的数据相同 由联邦铁路管理局颁布，如49 CFR第229.129部分所述。

Federal regulations require the testing of sound emissions from horns located on railroad locomotives. This Standard specifies an alternate method for compliance with the Federal requirements in metropolitan areas where tests cannot be conducted in an outdoor space free of obstructions. The data that result from this procedure are equivalent to those that derive from the procedure promulgated by the Federal Railroad Administration as described in 49 CFR Part 229.129.