File – A CSX freight train passes through Homestead, Pa., Monday, Feb. 12, 2018. A Trump-era rule allowing railroads to haul highly flammable liquefied natural gas will now be formally put on hold to allow more time to study the safety concerns related to transporting that fuel and other substances like hydrogen that must be kept at extremely low temperatures when they are shipped, regulators announced Thursday, Aug. 31, 2023. (AP Photo/Gene J. Puskar, File)

OMAHA, Neb. (AP) — A Trump-era rule allowing railroads to haul highly flammable liquefied natural gas will now be formally put on hold to allow more time to study the safety concerns related to transporting that fuel and other substances like hydrogen that must be kept at extremely low temperatures when they are shipped. The rule was challenged in court right after it was announced in the summer of 2020. The Pipelines and Hazardous Materials Safety Administration says the uncertainty about the rule on transporting the fuel known as LNG kept railroads and gas companies from investing in it. So railroads never hauled any LNG.