The U23-C is a General Electric locomotive equipped with a 2250 HP engine.

In 1972, the first units of a total of 170 locomotives were produced, the delivery of which was divided into two batches. The first batch, produced at GE-Campinas, included a total of 80 locomotives (3801 to 3880), weighing 180 tons. The second batch had a total of 90 locomotives (3901 to 3990), of which the first 20, 165t, (3901 to 3920), were imported from GE-USA and were packed in Cachoeira Paulista (SP), therefore, commonly called “Cachoeirinhas”. These only had their tricks coupled in Brazil.

At RFFSA, despite being basically intended for traction of freight trains, especially ore, the U23Cs were also present on the Vera Cruz (BH-RJ) and Santa Cruz (SP-RJ) trains.

Currently, U23-Cs form a significant part of the MRS fleet.