Background and overview
JR East converted 205‑0 series EMUs—displaced from the Yamanote Line by the introduction of the E231‑500 series—into 205‑1100 series DC commuter electric multiple unit (EMU) trains between 2004 and 2005. These conversions, which included shortening the formations to three‑car sets, were undertaken to replace the aging 103 series operating on the Tsurumi Line.
Car body
The carbody of the 205‑1100 series measures 19,715 mm in length and 2,800 mm in width, with a bogie centre distance of 13,800 mm. The structure is primarily composed of stainless steel, except for the bolster beams, the end sections of the centre beam, and selected cross beams, which are fabricated from weather‑resistant steel plate (Steel Plate Atmospheric). The exterior features unpainted bead‑stiffened stainless‑steel panels with waistline and headline bands finished in a combination of sky blue and yellow running the length of each car below and above the windows.
Class Kuha205‑1100 vehicles were converted from Class Saha205‑0 intermediate trailer cars, while Class Kumoha204‑1100 vehicles were converted from Class Moha204‑0. These conversions included removing the original end structure and the side panels adjacent to the end windows, welding a reinforced front frame to the cut body end, and mounting a non‑gangwayed high‑strength composite structure—consisting of phenol‑resin foam and paper honeycomb covered with fibre‑reinforced plastic panels—onto the reinforced frame. An obstacle deflector is fitted beneath the cab, and the driver’s cab is elevated 300 mm above floor level to improve forward visibility and provide additional protection against obstacles at level crossings. The horizontally curved windscreen, finished in black at the upper portion with ceramic coating, is installed at the cab end. An LED destination display is mounted centrally behind the upper portion of the windscreen. Lighting equipment consists of two high‑intensity discharge (HID) lamps flanking the destination display and two externally mounted taillights.
Each car is equipped with four double‑leaf automatic sliding doors, each 1,300 mm wide. Door operation is controlled by TK4J units installed beneath the bench seats. Between the doors, the side panels feature pairs of drop windows measuring 920 mm in width, with additional drop windows provided at each end of the carbody. A destination rollsign is also mounted on each side of the carbody.
Each car is fitted with a roof‑mounted AU75G air‑conditioning unit rated at 42,000 kcal/h, flanked by five roof‑mounted draught ventilators.
Couplers between married‑pair motored cars use drawbars, while all other connections employ tightlock couplers.
Bogies
The powered bogies are designated as DT50 or DT50D, while the trailer bogies are classified as TR235 or TR235D, depending on the original vehicles from which they were converted. Both types feature bolsterless secondary air suspension and conical multilayer rubber‑spring journal supports. Traction force is transmitted via the centre pin and multilayer rubber‑spring draw gear. The side beams of the bogie frame are straight in profile, and the bogie transom incorporates seamless pipes to achieve a lightweight and simplified structure.
Power transmission utilizes a parallel cardan‑shaft drive system with a hollow shaft. The gear ratio is 6.07. Corrugated wheels are adopted to reduce weight, and a compound circular wheel profile is employed to minimize lateral forces exerted on the track.
The braking configuration varies by bogie type. Powered bogies are equipped with single‑tread brake rigging, while trailer bogies combine a single‑disc brake device with single‑tread brake rigging to enhance overall braking performance.
Powertrain and ancillary equipment
Series‑wound brushed DC traction motors (MT61), each rated at 120 kW, are employed. The eight traction motors on Class Moha205‑1100 and Class Kumoha204‑1100 vehicles are controlled by the CS57 armature‑resistance traction control system, which incorporates field‑added excitation control. A naturally ventilated traction‑resistor unit designated as MR159 or MR159A is used. During the armature‑voltage control stage, armature‑resistance control and series–parallel control are applied. During the field‑weakening stage, the HS52 or HS52A field‑added excitation system indirectly regulates the field current by controlling the current of the inductive shunt. Forced‑field control provided by the field‑added excitation system enables regenerative braking. At low speeds, regeneration voltage is maintained through series–parallel control, allowing regenerative braking to remain effective down to approximately 20 km/h. If regenerative‑braking performance falls below the required threshold, pneumatic braking is automatically applied to supplement the braking force.
Current collection is handled by a PS21 lozenge‑type pantograph mounted on the roof of Class Kumoha205‑1000 vehicles. Class Kumoha204‑1100 vehicles converted from Class Moha 204‑0 that were not originally fitted with a motor‑generator unit are additionally equipped with an auxiliary power supply unit (SC72) rated at 160 kVA, as well as the existing motor‑driven air compressor (MH3075‑C2000M), both mounted beneath the floor.
The brake system features an electrically commanded pneumatic braking system
with regenerative‑braking capability, resulting in improved brake response.
End vehicles are equipped with an onboard ATS‑P signalling system installed
in the cab due to space constraints caused by the extensive ancillary equipment
mounted beneath the floor..
Accommodation
The passenger saloon of the 205‑1100 series EMU is configured with fully
longitudinal seating to maximize capacity and facilitate smooth passenger
flow during boarding and alighting. Each bench is fitted with end partition
panels to delineate individual seating areas. Hanging straps are installed
throughout the passenger compartment to support standing passengers in
two parallel rows along the ceiling. The air‑conditioning ductwork is installed
above the ceiling to maintain a clean interior profile, with slit‑type
vents providing evenly distributed airflow. Illumination is provided by
fluorescent fixtures arranged in two parallel rows along the ceiling. The
control desk is fitted with a single‑handle master controller operated
with the left hand.
Modification
Pantograph replacement
The pantographs of Class Moha205-1100 vehicles were replaced with PS33E single‑arm pantographs in 2009.
Operations
In 2004, the 205‑1100 series entered revenue service on the Tsurumi Line.
Subsequently, E131‑1000 series EMUs began replacing the 205‑1100 series on the Tsurumi Line in 2023, and the 205‑1100 series was completely withdrawn and fully scrapped in 2024. |
|
| Technical Data |
| Items |
Data |
| Supply Voltage |
1,500 V DC |
| Service
speed, etc. |
Acceleration: 2.5 km/h/s Deceleration: 2.8 km/h/s Service speed: 100 km/h |
| Length |
19,500 mm |
| Width |
2,800 mm |
| Height |
4,140 mm |
| Bogie |
DT50/DT50D (motored) TR235/TR265D (trailer) |
| Collector |
PS33E |
| Traction
motor |
MT61 (120 kW) |
| Gear ratio |
6.07 |
| Traction system |
Field added
excitation control: CS57 |
| Air conditioner |
AU75G (42,000 kcal/h) |
| Designed
by |
JR East |
|
|
