2001
The Federal Signal 2001 Series is a line of outdoor warning sirens produced by Federal Signal. Variations include the 2001SRN, 2001SRNB, and the 2001-130.
2001SRN
The 2001SRN siren began production in 1999, replacing the Thunderbolt with a much less complex, and thus more reliable, design. It also introduced battery backup. This model is identifiable from its successors by the large, rectangular rotator box design borrowed from the Thunderbolt Series as well as the "2001DC" label on the rotator. This series came in two forms, the early "Roundback" and the later "Squareback", referring to the shape of the rear housing. Roundback models were only produced for a short time and much less common than the Squareback variant, with a few of the known Roundback sirens being located in Fostoria, Ohio; Romeoville, Illinois, Southaven, Mississippi; and Prior Lake, Minnesota. Aside from the rear housing, the two variations are identical.
2001SRNB
The 2001SRNB was the second generation of Federal Signal's 2001 series. The design is similar to its predecessor, the 2001SRN, with the most notable change being a refined stator design, increasing the sound output to 128 dBc at 100 feet. Secondly, a new square gear-driven rotator replaced the belt-driven rotator originally inherited from the Thunderbolt.
2001-130
The 2001-130 is the latest version of Federal Signal's 2001 Series, with production starting in 2006. A support beam, which previously ran across the intake and restricted airflow, was relocated. The rear housing was also made taller, possibly to further improve airflow. This model can be identified by the 2001-130 label on the rotator housing as well as the increased rear housing height.