Master Car Builders' Association (MCB)

The Master Car Builders' Association (MCB) was a historic American railroad organization founded on September 18, 1867 in Altoona, Pennsylvania to address the problems created by interchanging freight cars before industry standards existed. It is a key predecessor in the lineage of the modern mechanical standards now maintained by the Association of American Railroads (AAR).

The objects of the Master Car Builders' Association were the advancement of knowledge concerning the construction, maintenance, and service of railroad cars and their parts, pursued through committee investigation and discussion in conventions. The Association sought to bring about uniformity and interchangeability in the parts of railroad cars and to adjust the mutual interests arising out of the interchange and repair of cars. Its actions, however, were only recommendatory in character and were not binding upon its members or the companies they represented.

The MCB later merged with the American Railway Master Mechanics' Association to become the Mechanical Section of the American Railroad Association (ARA), part of the consolidation that ultimately produced the AAR.

Notable Events

• 1882: Reorganized to broaden the scope of its work and include representation by each railroad.
• 1888: Adopted the automatic coupler (the Janney/MCB coupler contour) as standard.
• Late 1880s: Adopted the automatic air brake as a standard, advancing train-braking safety.
• Early 1900s: Extended its standards work to the construction of specialized cars such as tank cars.