We, the undersigned trade associations have members that collectively employ millions of Americans in all sectors of the U.S. economy. Our members are committed to environmental stewardship and to policies that encourage domestic emissions reductions that address climate change. Yet, we write to raise serious concerns about an authorization request from the California Air Resources Board (CARB) pertaining to rail locomotive emissions and respectfully urge you to deny their petition. This regulation from CARB has the potential to create significant disruptions in the supply chain for all sectors of the U.S. economy, especially manufacturers and shippers who rely on consistent, reliable rail service. This rule could lead to delays for businesses and increased costs for both shippers and consumers that could ultimately lead to a massive supply chain crisis. If railroads are forced to spend large amounts of money to ensure compliance with this rule, those costs will be passed along the entire supply chain and could inhibit rail service at facilities across the country – not just in California.