Background and overview
JR East developed the 205‑500 series DC commuter electric multiple unit (EMU) trains in 1991 to coincide with the electrification of the Sagami Line.
Car body
The carbody of the 205‑500 series measures 19,500 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 blue green and light blue running the length of each car below and above the windows.
The non‑gangwayed cab ends, which have no gangway door, are fully covered with decorative FRP panels. The obstacle deflector is fitted under 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 vertically curved windscreens are divided into a wide glass pane on the driver’s side and a narrower pane extended downward on the assistant driver’s side. A destination rollsign is mounted centrally behind the upper portion of the wider windscreen, while an operation‑number indicator—displaying the trainset‑level scheduling identifier—is implemented using a rotary disc located behind the upper portion on the left side of the wide windscreen. End vehicles are equipped with a longitudinally arranged sealed‑beam headlight with a taillight positioned below.
Each car is equipped with four double‑leaf automatic sliding doors, each 1,300 mm wide. Manual operation is enabled via push button controls adjacent to each door. 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. Door operation is controlled by TK112 units employing pneumatic direct‑drive mechanisms mounted on the door headers. Additional equipment includes a destination rollsign and two loudspeakers mounted on each side of the carbody to support passenger announcements.
Each car is fitted with a roof‑mounted AU75G air‑conditioning unit rated at 42,000 kcal/h. Class Moha204-500 vehicles are equipped with four roof‑mounted draught ventilators; end vehicles feature five, while other variants feature six.
Couplers between married‑pair motored cars use drawbars, while all other connections employ tightlock couplers.
Bogies
The powered bogies are designated as type DT50D, while the trailer bogies are classified as type TR235D. 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 shape, and the bogie transom incorporates seamless pipes to achieve a lightweight and simple construction.
Power transmission utilizes a parallel cardan drive system with a hollow shaft. The gear ratio is 6.07, optimized to provide the same high‑acceleration performance at starting and the same maximum service speed as the 201 series EMU. Corrugated wheels are adopted for reduced 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, deliver high torque at both low and high speeds by expanding the field‑weakening ratio to 35%. The eight traction motors on Class Moha205-500 and Class Moha204-500 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 MR159A is employed. During the armature‑voltage control stage, armature‑resistance control and series–parallel control are applied. During the field‑weakening stage, the HS52B field‑added excitation system indirectly regulates the field current by controlling the current of the inductive shunt. Forced‑field control provided by the HS52B 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 braking force.
Current collection is handled by a PS21 lozenge‑type pantograph mounted on the roof of Class Moha205-500 vehicles. Class Moha204-500 vehicles are equipped with a brushless motor‑generator unit (DM106) delivering 190 kVA, and a motor-driven air compressor (MH3075A-C2000M), both mounted beneath the floor. The brake system features an electrically commanded braking system with regenerative‑braking capability, resulting in improved brake response. End vehicles are equipped with onboard ATS-S signalling system beneath the floor.
Accommodation
The passenger saloon of the 205‑500 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. Overhead luggage racks are constructed with pipe‑frame structures. Hanging straps are installed throughout the passenger compartment in two parallel rows along the ceiling to support standing passengers.
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 master controller employs a lateral‑motion operating handle. A monitoring equipment designated as MON5 is mounted on the right of the control desk to provide the guidance for the driver.
Modification
The pantographs of Class Moha205-500 vehicles were replaced with PS33E single‑arm pantographs in 2009.
Operations
Thirteen sets of 205‑500 series EMUs were assigned to the Sagami Line and entered revenue service in 1991.
The 205‑500 series continued to operate on regional services on the Sagami Line; however, replacement by the E131‑500 series began in 2022. The 205‑500 series was completely withdrawn and scrapped in 2022. |
|
| 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 (motored) TR235 (trailer) |
| Collector |
PS21 |
| 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 |
|
|
