Tokyo Metro 9000 series

The Tokyo Metro 9000 series is a Japanese city commuter electric multiple unit operated by the Teito Rapid Transit Authority and its successor Tokyo Metro since November 1991.
==History==
The 9000 series was conceived in 1991 as a train that would look towards the future with 20th century concepts, using advanced technology but having a refined design.
The first set, four-car set 9801, was delivered some time in 1990 and entered service in November 1991; more sets were later built and put into service progressively. The 9000 series was the first Eidan train to use a variable frequency drive as it was found that the use of chopper-controlled motors would have some limitations when scaling the steep gradients of the line. Despite the first set being a four-car set, all remaining sets were six cars long; eventually, the first set was reformed as a six-car set with two new-build cars being inserted into the set. A total of 21 sets were produced in five batches, labeled batches A (9801, 9803, 9805, 9807), B (9802, 9804, 9806, 9808), C (9809 – 9815) and D (9816 – 9821). 
When the TRTA was dissolved in 2004, ownership of the 21 sets was handed over to Tokyo Metro; two additional sets, 9822 and 9823, were produced in 2009 by Nippon Sharyo after production of the original 9000 series sets had stopped. In addition to being used on the Tokyo Metro Namboku Line, the sets are also used for through-running through to and from the Tokyu Meguro Line and Saitama Rapid Railway Line. All sets are in service and are based at Ōji Depot.
Tokyo Metro announced that the sets would be extended from six to eight cars long in 2023; the first set to receive these modifications was 9808, reentering service on 16 December 2023. The new-build cars are manufactured by Kawasaki Railcar Manufacturing.
==Design==
The 9000 series use a fairly modern design for the time with an unpainted body made of an extruded aluminum alloy. The design of the first 21 sets is extremely similar to what is seen on the 05 series sets; the batch E sets sport a very different appearance.
==Specifications==
Construction is of an extruded aluminum alloy. End cars are 20 meters long, 2.78 meters wide and 4.14 meters high. The first 8 sets used gate turn-off thyristor variable frequency drives manufactured by either Mitsubishi or Hitachi (later-specification); sets 9805 and 9807 used Mitsubishi GTO drives that produced a wailing sound that steps up in pitch while sets 9802, 9803, 9804, 9806 and 9808 used later-specification Hitachi GTO drives produce a constant wailing sound. Set 9801 is unique in that it uses a combination of both drives, which creates a raucous and distorted cadence.
Sets 9809 to 9821 use insulated gate bipolar transistor drives, with each batch using a different type of drive; sets 9802, 9804, 9806 and 9808 to 9813 use three-level IGBT drives produced by Hitachi that produce a shrill sound, sets 9814 and 9815 use early-specification three-level IGBT drives produced by Mitsubishi which produce a hissing sound that increases in intensity and sets 9816 to 9821 use two-level IGBT drives produced by Toshiba which produce a hissing sound that slowly increases in intensity. Sets 9822 to 9823 both use current-specification two-level Mitsubishi IGBT drives which produce a hissing sound; both sets also feature single-arm pantographs instead of lozenge-style pantographs.
9801 to 9808 underwent "Type B" life extension refurbishment from 2016 to 2019. Improvements to the sets made while the refurbishments were carried out including replacing the three-color LED destination indicators with full-color LED destination indicators, addition of a "sine wave" design on the side of the trains, replacing the interior destination indicators with LCD screens and updating the traction systems; these were changed from GTO inverters to Mitsubishi silicon carbide-based MOSFETs, which produce a soft hissing sound.
==Gallery==
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Tokyo Metro 9000 9822 Tamagawa 2017.jpg|9822 in July 2017
</gallery<
==References==
*Wikipedia.org
Category:Tokyo Metro trains
Category:Kawasaki locomotives
Category:Nippon Sharyo locomotives
Category:Tokyu Car locomotives
Category:Electric trainsets
Category:TRTA trains