Oil companies and railroads have united to fight some proposed federal rules on oil-train safety after a year of pointing fingers at each other over explosive accidents.

Industry groups representing railroads and energy companies on Tuesday told the U.S. Transportation Department that they need more than two years to build safer railcars to haul crude.

The department's Pipeline and Hazardous Materials Safety Administration in July proposed safety rules for oil trains that would create new standards for tank-car brakes, other components, speed limits and special routes around populated areas. The department's proposals also seek to scrap some of the oldest railcars while upgrading others.

The proposals were in response to a series of oil-train accidents that began in July of last year with a derailment and fireball in Lac-Mégantic, Quebec, which killed 47 people. Oil companies have said track problems and human error caused the accidents, while railroads have questioned the crashworthiness of tank cars and questioned the combustibility of the oil.

Comments about oil-train regulations poured in from the public, industries and elected officials, according to the agency's website. Citizens asked for everything from an outright ban on rail shipments of crude oil to special routes that keep them out of national parks. The county executive in Albany, N.Y., which has become a major oil-train hub, called on the federal government to take steps such as treating crude to make it less volatile and improving the safety of railcars.