2001 series

The Federal Signal 2001SRN was the first model of the 2001 series. Early models had a round rear housing and are colloquially referred to as "roundbacks". Mechanically the roundbacks are no different from the "squarebacks" that followed.

The 2001SRN is identifiable from its successors by the large, rectangular rotator box design borrowed from the Thunderbolt as well as the "2001-DC" label on the rotator.