Definition: The name "B unit" or "booster" is given to a cabless diesel locomotive. B units are used in multi-unit locomotive consists behind cab units. They are then controlled remotely from the leading cab unit and increase the train's total pulling power. Because they don't have a control cab for engineers, B units are less expensive to produce than the cab equipped A units. EMD E and F series locomotives as well as the Alco P series were typically available in both A and B unit versions.
Also Known As: booster unit