Toei 12-000 series

The 12-000 series (read as 12,000) is a Japanese linear-motored city commuter electric multiple unit. Built from 1990 to 2001 for the Toei Subway, the 12-000 series was the first linear motored train to enter service in the Tokyo area and are used on the Toei Ōedo Line.
==History==
The 12-000 series was a completely new design that was conceived in 1986 as a new subway design for the 21st century, in addition to having energy saving measures among other things. The first set, two-car pre-production set 12-001, was delivered to Toei from Nippon Sharyo in March 1986 and was test run from then on. Originally built with conventional traction motors, the set had its motors converted to linear motors in 1987 and was tested on a dedicated section of track at Magome Depot; it was later decided on 21 December 1988 that the then-soon-to-be-built Ōedo Line was to use linear motor propulsion as a result of these tests. The set carried out a few more tests and fell into disuse; the set was then retired and preserved at the Chihaya Flower Park, where it has remained since February 1991.
With the test results of set 12-001 showing, a batch of 53 full-production sets was produced by Hitachi, and have been used on the line since its opening on 10 December 1991. The first batch of sets, sets 12-101 to 12-501, were retired in June 2016; the remaining sets are also scheduled to be replaced by newer 12-600 series sets in the coming years. All sets are based at Kiba Depot.
==Design==
The 12-000 series uses a fairly modern design with a body made of an extruded aluminum alloy. Sets 12-101 to 12-501 had painted white aluminum bodies, while the remaining sets had unpainted aluminum bodies. The prototype set had a somewhat streamlined design with unpainted stainless steel bodies.
===Variations===
;Cab design variations
There are three cab design variations of the 12-000 series; one is used for the prototype set and the other two are used for the full-production sets.
Toei 12-000 001 Chihaya 2008.jpg|12-001 at Chihaya Flower Park, Toshima, Tokyo in June 2008
Toei 12-000 058 Kiba 2007.jpg|12-051 in November 2007
==Specifications==
Construction is of an extruded aluminum alloy. End cars are 16.25 meters long, 2.49 meters wide and 3.145 meters high. The prototype set, set 12-001, had a gate turn-off thyristor system produced by Toshiba, though it is unclear how it sounded like as no audio recordings are known to exist.
Full-production sets 12-101 to 12-501 used Hitachi GTO inverters which produced a low droning noise, while the remaining full-production sets used insulated gate bipolar transistor variable frequency drives also produced by Hitachi which produce a high-pitched screech. A software change caused the IGBT drives from sets 12-601 to 12-531 to produce a different sound, this time being a loud shrieking sound.
The use of linear motors in the sets gave the sets an extremely unique droning noise once the sets reached high enough a speed; this characteristic is only found on linear-motored trainsets. In addition to the odd-sounding motors, the linear motor system does provide some benefits, such as allowing for smaller cars and tunnels; however, this disallows the 12-000 series sets from performing through-running to and from other lines due to technological incompatibilities, in addition to most other lines having technology that only works with rotary-motored trains.
While it is technically possible for rotary-motored trains to operate on the Ōedo Line, where the 12-000 series sets see service, a different loading gauge, track gauge and smaller tunnels prevent such occurrences.
Despite the Ōedo Line being the first linear motor-powered subway line in the Tokyo region, it is not the first linear motor-powered subway line in the country; that honor goes to Osaka Metro's Nagahori Tsurumi-ryokuchi Line with their 70 series sets.
==References==
*Wikipedia.org
Category:Toei trains
Category:Electric trainsets
Category:Hitachi locomotives
Category:Nippon Sharyo locomotives