Railroad Advancement of Innovation and Leadership with Safety Act or the RAILS Act This bill seeks to promote alternative approaches to railroad safety through self-regulation. Specifically, the Department of Transportation (DOT) shall: before proposing or adopting a rule, consider an approach that specifies performance objectives rather than identifies or requires the specific manner of compliance that a regulated entity must adopt; before issuing a proposed rule, publish an advance notice of proposed rulemaking unless the proposed rule is not likely to result in a "significant rule" (i.e., a rule that has an annual effect on the economy of $100 million or more or meets other specified criteria); before issuing any proposed rule or final rule, conduct a regulatory impact analysis to evaluate the proposed rule or final rule; by June 1, 2019, and at least every five years thereafter, complete a comprehensive review of the regulations, orders, and guidance documents issued; and include, in each significant rule prescribed on or after December 31, 2017, a framework for assessing the rule's effects. DOT may waive compliance with any part of a regulation prescribed or order issued if the waiver: (1) is in the public interest; (2) requires the recipient to adopt an alternative technology, practice, or system that could achieve a level of safety equivalent to or greater than that which would be obtained in the absence of the waiver; and (3) includes a DOT-approved evaluation framework.