Peaceful Learning Act of 2018 This bill directs the Department of Transportation (DOT) to enter into an agreement with the National Academy of Sciences to study railway noise in the United States. DOT must: (1) establish a single system of measuring railway noise that has a highly reliable relationship between projected railway noise exposure and surveyed reactions of individuals to noise and is applied uniformly in measuring railway noise near urbanized areas, (2) establish a single system for determining the exposure of individuals to railway noise in urbanized areas, and (3) determine minimum standards for railway noise levels on the property of a school located in an urbanized area. Each rail operator shall submit to DOT a noise exposure map showing any areas of nonconforming railway noise levels that adversely impact a school located in an urbanized area and are caused by operations of the rail operator. Rail operators who submit a noise exposure map may also submit a noise compatibility program. DOT may award grants to carry out noise compatibility projects.