2001

Federal Signal Model 2001
A Federal Signal 2001-130, located in Cowpens, SC. Photo credit to TrainsandSirens1.
Company	Federal Signal Corporation
Produced	1988-Present
Type	Rotational Electromechanical
Sound output	125-130 dB @ 100 ft
Horsepower	6-6.5 hp
Voltage	48 V DC
Preceded by	Federal Signal Thunderbolt Federal Signal 500 Federal Signal RSH-10
Documentation	Manual

The 2001 is a series of DC-powered rotating mechanical sirens produced by Federal Signal Corporation over the past 30+ years, as a replacement to Federal's popular but aging Thunderbolt series.

Boasting a very high sound output with battery backup capabilities, the 2001 series has become one of, if not the most popular option for cities seeking a DC siren system all across the country. It competes with ASC's T-128 as the most popular rotating mechanical siren on the market, and is part of Federal's current main lineup alongside the 508-128 rotational and ECLIPSE omnidirectional sirens.

Overall Design

A privately owned 2001-SRNB with the nose cone and projector removed. It is owned by Nirvoxide.

While the 2001 series has gone through many changes over the years, all 2001 sirens take the same general form. The siren's rotor and stator are located in the horn, just behind the nose cone. Unlike nearly every other rotational siren, the chopper on the 2001 faces towards the rear, with the siren's 6.5 hp (originally 6 hp) 48 V DC motor located inside the nose cone in front of it.

The 12-port, 13-inch rotor used in this siren is the same as Federal's long-discontinued C1 1/2 Model 3, with small "throats" attached to the stator ports which direct the sound out and forwards out into the main projector horn of the siren. The rotor has 4 long vanes and 8 short vanes, giving it a 4-port undertone. This design is efficient, gives the 2001 its distinctive "rasp", and allows the siren to boast a significant sound output without the need for a blower or high-powered motor.

The core and projector assemblies are attached to the square/rectangular main housing located behind the horn, which contains the collector ring tube and wiring along with the siren's dual intakes located on the bottom of the housing. The intakes are protected by mesh screens. The top of the housing has a slightly pyramid-shaped protrusion, which prevents rainwater from pooling on top of the housing and causing corrosion.

The collector ring tube is reused from the Thunderbolt in all models. The 2001's rotator is located below the main housing and has seen the most changes over the siren's production. All 2001 sirens include and run on Federal's FC controller. Since its production began in 1988, the 2001 has been produced in several different forms, with four distinct models:

Models

2001-SRN (1988-2002)

The 2001-SRN was the earliest model of 2001 produced, being introduced into Federal Signal's lineup in August 1988. The 2001-SRN was intended as a lower-maintenance and DC-capable replacement for the Thunderbolt.

The 2001-SRN's design is very typical for a rotational siren and took some design cues from the earlier 500 series. The nose cone is conical, containing a 6 hp 48 V DC motor. The 2001-SRN is able to reach 126 dB at 100 ft. It reuses the Thunderbolt's belt-driven rotator, which allows the rotation speed to be adjustable from 2, 4, or 8 rpm.

A freshly restored 1st gen 2001-SRN, located in Deerfield Township, MI. Image credit to Sirens of Southeast Michigan.

1st generation "Roundback"

The first generation 2001-SRNs use a rounded rear housing, and are colloquially known as "roundback" models. They have "FEDERAL 2001-DC" stickers on the rotator housing, advertising the siren's DC power capabilities. The "roundback" design differs from later models by its rear housing opening through a latch and hinges, allowing the top half of the rear housing to swing open for easy access to the chopper and wiring. Both the 1st and second generation used a horn that was constructed out of two sections joined together by bolts in the middle on each side. Both the "roundback" and the later "squareback" 2001-SRNs used screens placed at the front of the horn, held on by rubber gaskets. These gaskets have often failed over time, causing them to droop from the horn. "Roundback" 2001-SRNs were produced from 1988 until 1990.

A diagram of the 2001-SRN's rotator.

2nd generation "Squareback"

The second generation 'Squareback' design was introduced in 1990, replacing the rear housing with a square design. Other than the rear housing, the 2nd generation 2001-SRN was identical to the "roundback" design. Rather than being accessed through a door atop the housing, the rear housing is now accessible through a removable rear panel. The 2nd generation SRNs kept the "2001-DC" stickers, although their official name was still considered the 2001-SRN.

3rd generation

In 1996, the 2001-SRN received a third generation which improved upon the design. The horn was altered slightly where it attached to the "throats", due to a stator design change. The horn was made slightly larger, with a single-piece horn instead of the older two-piece horn. Early 3rd generation units used the old nose cone from the 2nd generation 2001-SRN, before it was switched to the larger, rounder nose cone that the rest of the 2001 series would use. The mesh screen would also be relocated, now being located in front of the 12 throat holes instead of at the front of the horn. This was due to the older mesh screens often falling off if the rubber gaskets failed.

A 4th generation 2001-SRN, located in Celestine, IN. Image credit to DSRX100.

4th generation

The final and fourth generation of the 2001-SRN would be released in 1998, with the housing and rotator becoming slimmer and the 8 RPM rotation speed option being removed. The "2001-DC" stickers were discontinued, leaving the rotator panels blank. In the year 2001, the stator was redesigned which slightly boosted the performance of the siren, increasing its decibel rating to 128 dB @ 100 ft. The 4th generation 2001-SRN would be sold until 2002, when it was replaced by the 2001-SRNB, which required less maintenance while retaining the 4th gen SRN's boosted performance.

2001-SRNs of all generations are still very common to find in service, including several roundback units. The 2001-SRN was able to match the Thunderbolt's sound output without the need for a blower while adding battery backup, causing the 2001-SRN to completely replace the Thunderbolt in 1990. A three-signal variant was offered for early 2001 units, though none were ever sold.

Note: While the stickers on many 2001-SRNs say "2001-DC", the 2001-SRN is NOT named the 2001-DC in any official capacity. "2001-DC" refers to the fact that 2001 sirens run on DC motors, and any 2001 siren running on DC power is a 2001-DC, while 2001s running on an AC rectifier are 2001-ACs. "2001-DC" was the name used by Federal Signal to advertise the siren's then-new DC powered capabilities, which is why many 2001-SRNs had "2001-DC" stickers.

A Federal Signal 2001-SRNB, located in Brunswick, OH. Image credit to Sirens of NE Ohio.

2001-SRNB (2002-2006)

The 2001-SRNB (Model 2001-SRN, Beltless) was the 5th generation successor to the 2001-SRN, and was introduced in 2002. The 2001-SRNB is essentially a 4th generation 2001-SRN with an improved rotator mechanism. Rather than using the rectangular belt-driven rotator from the Thunderbolt, the 2001-SRNB introduced a new cube-shaped direct-drive rotator which eliminated the need for belts and made the siren require less maintenance. The rotator runs at 2 RPM from factory, and is adjustable up to 6 RPM. The DC motor is directly coupled to the gear reducer, which then spins the rotator's main gear. The chopper motor was also upgraded from 6 hp to 6.5 hp, which increased the siren's sound output to 128 dB at 100 ft.

The 2001-SRNB also introduced the decals that every later 2001 would use. Early 2001-SRNBs used the smaller FS logo from the 2001-SRN, but this was updated to the larger logo in 2004. The 2001-SRNB had the shortest production run, only being produced for 4 years from 2002 until 2006. Despite its short production span, it proved to be very popular and is still a common find today.

A Federal Signal 2001-130, located in Champaign, IL. Image credit to Glist.

2001-130 (2006-present)

The 2001-130 is the 6th generation, newest and best performing model in the series and the current model of 2001 in production as of today. Rather than using the square housing of the 2001-SRN and SRNB, the 2001-130's housing is taller and rectangular in shape. This is a correction for a design flaw of previous 2001 siren models, where the collector ring assembly and support beam for the housing blocked the chopper's intake partially, hindering performance. The 2001-130's taller housing allows for the chopper to now be above the collector ring and support assemblies, which greatly improves airflow to the chopper and increasing the siren's output to 130 dB at 100 ft.

The 2001-130 is easily the most popular siren in the series, with systems of 2001-130s being installed all across the country and often replacing older systems and is still being produced today.

A Federal Signal Equinox, located in Star Prairie, WI. Note the larger, fewer throats compared to the 2001-130. Image credit to mn_sirens.

Equinox (2010-present)

The Equinox was created as a lower pitched alternative to the 2001-130. While not officially part of the 2001 family, the Equinox shares many characteristics of its design with the 2001-130, essentially being the latter with an ECLIPSE rotor and 8-port stator. The Equinox can be difficult to visibly differentiate from the 2001-130 at a glance, due to being very visually similar. Besides the "EQUINOX" sticker replacing "2001-130" on the rotator box, the stator is noticeably different between the two models if one looks closely. The 2001-130 has 12 individual projectors on the stator with narrow spacing between them, where the Equinox only has 8 with rather large gaps between them.

Initially, these sirens were rolled out on special order to the Beaver Valley and Perry nuclear power plants, that had wanted sirens with a lower peak pitch (500hz, 8-port) than a 2001-130 that would in theory have a longer range and penetration due to the lower frequency. The first system of Equinox sirens were installed in 2010 around the Beaver Valley Power Station in Shippingport, Pennsylvania. The next system was installed at another plant, Perry, beginning in 2012. While these are considered to be the first systems of Equinoxes, one was installed in New Carlisle, Ohio, in 2010, so it is possible that municipalities were able to order the Equinox on special request during this period, prior to its introduction as part of the 2001 series in 2014.

The Equinox was a bit of a rush job, as Federal had little time to design the siren. The main design flaw is the use of the ECLIPSE's rotor, which has an integral intake cone that juts out into the rear housing. This severely hampers the flow of air into the siren and reduces its output to 125 dB at 100 ft. Federal would recognize this problem and succeeded the Equinox with the much-improved 508-128 in 2011. The 508-128 resolves the Equinox's airflow issues, providing a significant boost in output over the latter. Despite having been replaced by the 508-128, the Equinox continued to be sold as a special order option until 2014, when it was publicly released as a lower cost alternative to the 508-128. It is still currently in production, with roughly 500 units sold as of 2025.

Controllers

The current controllers that Federal Signal sells to operate the siren are the DCFCB and 2001-AC which are used for 120VAC power and 208 or 220/240VAC respectively. Both controllers have NEMA 4X aluminum cabinets with 2 48VDC chargers. 2001-DC used to be the name used for the DC controller sold for the siren and is where the nickname for the 2nd gen 2001-SRNs (the ones with the 2001-DC sticker) came from.