Built by the Illinois Central Railroad at its' Burnside shops in Chicago with the instruments provided by the University of Illinois (the car jointly owned).  The dynamometer car is a rolling laboratory that tests the pulling power of locomotives.  The front coupler is attached to the frame by a hydraulic cylinder.  The pull of a locomotive moves a piston in the cylinder and measuring instruments in the car record the data.  The system is so sensitive it can detect the force of a person pulling on the coupler and so strong that it tested an engine pulling a 213 car coal train.  Number 30, a steel car,  is 60' long, weights 125,000 pounds. Test trips on the car could last for several days, and as a result, the car contains facilities to house and feed the test crew and a dining car cook: two staterooms for four people each; lockers, toilet, shower, and kitchen.  It also contains an operating compartment with recording table, instruments and tool bench. This car was last used behind a steam locomotive in 1952 and was only used once behind a diesel-electric in 1955.  It was donated in 1969 by the Illinois Central Railroad and the University of Illinois.