The Rc is a series of four-axle electric locomotives designed by ASEA in the sixties to replace older SJ locomotives like the D. They were the first thyristor-controlled locomotives of the SJ and were built in several variants for different types of trains. The Rb1, Rb2 and Rb3 in 1962 can be viewed as the prototype of the Rc, but these did not have thyristors yet. Production of 20 locomotives of the first variant Rc1 started in 1967. These were designed for mixed traffic and had a top speed of 135 km/h. Multiple working was possible with up to three locomotives.
The Rc2 was an improved variant that was built 100 times between 1969 and 1975. In 1970 and 1971, ten Rc3 were built which had a top speed of 160 km/h for use with fast passenger trains. In the nineties, 23 Rc2 were also rebuilt to the Rc3. The largest batch was the Rc4, of which a total of 130 were built between 1975 and 1982. These had again a top speed of 135 km/h for use with passenger and freight trains. In 1977, six of these were rebuilt into the Rm for iron ore traffic. These got a gear ratio for 100 km/h, other couplers and ten tonnes of ballast. These were used with three locomotives per train, but rebuilt back to Rc4 in 1997.
Between 1982 and 1986, 60 Rc5 followed which also had a top speed of 135 km/h. These were modernized in the area of electronics and in the comfort and safety of the crews. Finally, 40 Rc6 were built between 1985 and 1988 which had a top speed of 160 km/h like the Rc3, but all the modern features of the Rc5. Increased demand for fast passenger services led to the rebuild of all Rc5 into Rc6 between 1992 to 1995. Two Rc6 were even rebuilt for 180 km/h and designated Rc7, but high costs to modify existing passenger coaches for this speed ultimately resulted in these two being reverted to the Rc6.
Over the years, many Rc locomotives in use in Sweden were modernized. Green Cargo, the now independent freight branch of the state railways, started to equip their Rc2 with IGBT converters and air conditioning in 2007. Their Rc1 were not modified and withdrawals started in 2013. These locomotives were also the basis for several others in other countries. The class 1043 of the ÖBB was based on the Rc2 and later formed the basis for the class 1044. Amtrak borrowed a Rc4 in 1976, what led to the licensed production of the AEM-7 by EMD. Also the NSB El 16 was based on the Rc4, but had a modified body design and an increased output.