The basic legislation under which railroad labor relations are conducted was enacted in 1926. The Railway Labor Act was supported by both labor and management. This legislation was substantially revised in 1932, at which time the law prohibited the union shop (designed to eliminate the company unions organized by the railroads during the prior six year period) and provided for the establishment of a National Railroad Adjustment Board whose main task was the arbitration of grievance disputes.
In 1950 the law was changed to permit the union shop. Because the national board was deluged by grievance disputes, the law was further amended in 1970 to allow the establishment of special boards of adjustment to handle grievance disputes on individual railroads.
Finally, the Northeast Rail Service Act of 1981 amended the original legislation to establish more elaborate procedures to resolve labor disputes on commuter railroads.