Background and overview
In 1985, Japan National Railways (JNR) made a plan to deliver new electric
multiple unit (EMU) trains in order to relocate some 103 series EMU used
on Yamanote commuter services to Yokohama and Musashino lines to provide
additional capacity. Although JNR examined to deliver high-cost 201 series
EMU to Yamanote line, it was very difficult to reduce the cost of 201 series
much more and budget restraints of JNR prevented the construction of additional
201 series trains. And instead, JNR developed new field added excitation
traction control and light weight bolster-less bogies for next generation
suburban trains, giving good results. As the result, JNR decided to develop
next generation commuter EMU trains, 205 series, applying these new technologies.
Car body
They have 2800mm narrow body. Their body design incorporates stainless
steel in order to realize lightweight body, excepting bolster beams, the
body end part of centre beam, and some cross beams made of weatherproof
steel sheet (Steel Plate Atmospheric). Their bodies are 3.5t lighter than
201 series. Their skin of the bodies features unpainted bead processed
stainless sheet. They have the double yellow green waistline and headline
bands running the length of each car below and above the windows. The cab
end employs glabled shape and raised driver's cab. Windshcreens are asymmetric,
and electrolytic colouring aluminum black plate is fitted around windscreens.
They are equipped with 4 double-leaf automatic sliding doors and pairs
of double-hung unit assembled windows with the upper stage descending and
the lower stage rising on each side of the vehicles. Door case windows
between the doors and windows located at the end plate of the body are
omitted for light weight. Door operating equipments, TK4J, are fitted under
the seatings. Traditional roller-binding destination screens are fitted
on the body. An air conditioner, AU75G rated at 42,000kcal/h, is fitted
on the centre of their roof. Forced ventilators are fitted on the both
side of the air conditioner. The end cars are equipped with ATC signaling
system under the floor.
Bogies
Their bogies are DT50/TR235 featuring bolster-less secondary air suspension
and corn-shaped multilayered rubber spring journal supporting system. Traction
device of the bogie is multilayered rubber spring. Side beams of truck
frame features straight shaped, and bogie transam features seamless pipes
for the light weight and simple construction. Motored bogies employ single
tread brake device and trailer bogies employ single disk brake device and
single tread brake device. Corrugated wheels are adopted for the light
weight and compound circular wheel profile are featured in order to reduce
lateral force against tracks.
Traction unit and ancillary equipments
Series-wound brushed DC traction motors, MT61, with a power output of 120kW
realize larger torque at low speed and high speed by expanding the field
weakening ratio to 35%. The gear ratio is 6.07 to get high traction force
at starting. As the result, the acceleration performance and the maximum
service speed are same as those of 201 series. Eight traction motors of
Moha205 and Moha204 are controlled by armature-resistance traction control
system, CS57, featuring field added excitation control. At the armature
voltage control stage, armature resistance control and series-paeallel
control are applied. At the field weakening stage, field added excitation
system, HS52, indirectly controls the electrical current of field by controlling
the electrical current of inductive shunt. Forced field control by HS52
realizes regenerative braking. At low speed range, the voltage of regeneration
keeps by applying series-parallel control. So, the regenerative braking
is available until 20km/h. If the regenerative brake is not sufficient,
additional brake is provided by pneumatic friction brake. Class Moha205
vehicles are equipped with a diamond-shaped current collector, PS21. Class
Moha204 vehicles are equipped with a motor generator, DM106, with a power
output of 190kVA futuring brush less, for the auxiliary power supply. The
brake system is changed into the electric command pneumatic brake from
electromagnetic straight pneumatic brake, which was the standard of JNR
electric trains, and the brake response has been improved.
Accommodation
Seating is longitudinal throughout. Windshield plates are fitted at the
both end of seating. The air conditioning duct is fitted above the ceiling
in order to improve interior design and the outlets of cool air are slit
shape.
Operations of pre-production sets
4 fleets of pre-production type were delivered to Yamanote line and entered
the revenue services on the Yamanote line in Mar., 1985.
Mass-Production sets
The first full-production standard set was delivered in 1985. There are some noticeable differences over pre-production set. Side windows are changed into pairs of drop windows. Bogies are changed into DT50D/TR235D featuring double collar sealed roller bearing. 7-car sets were delivered for Tokaido-Sanyo ordinary services from 1986.
After the splitting of the former JNR into the new privatized JR companies
in April 1987, JR East, and JR West received 205 series vehicles.
JR East continued to deliver 205 series vehicles to Yamanote line. 205
series built by JR East has difference from those built by JNR in having
Luggage rack of 205 series built by JR East is assembled by stainless pipes,
although those built by JNR is aluminum wire-netting. After the completement
of delivery to Yamanote line, JR East delivered 205 series vehicles to
Nambu, Keihin-Tohoku, Sobu, Saikyo, Yokohama, Keiyo, and Musashino lines.
The front shape for Keiuo and Musashino lines are different from the others.
In 1990, JR East developed pre-poduction type of intermediate trailer vehicles
equipped with 6 double-leaf automatic sliding doors on each side to allow
rapid boarding and disembarking during peak periods. Seating is longitudinal
seating that were folded up to provide standing room only during the morning
peak until 10 a.m. Door operating equipments, TK102, are fitted above the
door header of the sliding doors. The luggage rack height is 1,950 mm to
be able to stand under the luggage rack. Stanchion poles are fitted at
the centre between the doors. An air conditioner is AU717 rated 50,000kcal/h,
fitted on the centre of the roof. Bodies are TR241B.
Mass-production type of intermediate trailer vehicles equipped with 6 double-leaf automatic sliding doors on each side, Saha204-0, were deliverd to Yamanote line in 1991. There are some noticeable differences over pre-production set. The luggage rack height is changed into 1,900 mm. A DC-DC converter is fitted in order to supply electrcity for the air conditioner.
In 1994, JR East delivered Saha204-100 vehicles to Yokohama line, allowing
rapid boarding and disembarking during peak periods. There are some noticeable
differences over Saha204-0. They are equipped with a wheelchair space.
A DC-DC converter is discontinued. Bogies are changed into TR246E adopting
the bolster-less air suspension, and axle arm type journal box supporting
system for the easier maintenance.
Latest operation status
205-0 series used on Yamanote, Soubu, Saikyo, Keiyo, Nambu, and Yokohama lines hae been displaced with E231 series or E233 series.
205-0 series used on Tokaido-Sanyo ordinary services had been displaced with 321 series and relocated to Hanwa line. The refurbishment programme was also commenced, with the same accommodation as 207 series, removing ventilators, and fitting loudspeakers, which a train conductor uses in order to guide passengers waiting at a station. But the vehicles used on Hanwa line were displaced with 225-5000 series and relocated to Nara line linking Kyoto and Nara. Now 205-0 series are used the ordinary services of Musashino and Nara lines. |
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