PORTLAND — State lawmakers sent a proposed oil train safety bill back for more work Friday after growing concerns that an amendment favoring the railroad industry had watered down key provisions on public oversight and financial accountability.The Oregon House was prepared to vote on House Bill 2131, but Rep. Barbara Smith Warner, a Democrat from Portland, made a surprise motion to send the proposed legislation back to the Joint Ways and Means committee for changes. The move came after environmental groups and residents of the Columbia River Gorge raised concerns about an amendment they felt neutered the state’s ability to police the railroads that run oil trains through communities.The bill was crafted at the start of the legislative session to address safety concerns after an oil train derailment near the small Columbia River Gorge town of Mosier sparked a fire near an elementary school that took hours to put out. Oil trains run continuously along tracks that parallel the Columbia River and pass through Mosier and other small communities.The bill was amended in May. Critics said the changes compromised transparency and public safety for the benefit of the rail industry.“Our intention was not to hide oil train safety plans from the public,” Smith Warner said before the vote on the motion. “This has been a complicated path, a long negotiation, and despite that there are times when the need for good policy overrides the need for consensus.”The railroad industry says making information about oil train routes and plans for a potential spill public would endanger national security by identifying where the easily identifiable, mile-long trains move. Smith Warner said Friday that the proposed bill had been crafted in a way that would help it survive legal challenges.