A newly-developed modular, electronically controlled engine test system for unmanned operation, has been chosen by Cummins Engine Company as part of a big POUND 13. 5M re-equipment scheme for its Darlington factory. The new installation, which features three test cells, started operating in mid 1986 when the firm's new B Series medium power diesels went into volume production, and its use could be extended to the larger-cylinder C Series at a future date. This article describes the installation, which was designed, supplied and installed by Schenck.