Just as the global supply chain flashes signs of returning to normal, a new crisis now threatens to disrupt the transport of a vast range of goods, from agricultural crops to lumber to coal.If tens of thousands of rail workers follow through on threats to strike as soon as Friday in pursuit of better working conditions, that would unleash potentially monumental havoc on the system used to move products from place to place.In a sign of how hard it could be to avoid a strike, the International Association of Machinists and Aerospace Workers District 19 said Wednesday that 4,900 of its members had rejected a tentative contract that the union had negotiated with the railroads. The Machinists union, one of a dozen at the center of complex talks …
