Electric Motor-Car Train

Electric Motor-Car Train 

a type of motor-car train in which the motor cars obtain power from an electric power network. Electric motor-car trains are used mainly on lines with heavy passenger traffic, such as suburban railroads and subways. Such a train may consist of motor cars and trailer cars, of which two are lead cars. The total number of cars ranges from four to 12; all the cars may be motor cars, as is characteristic of subways, or only some of them may be motor cars (see alsoMOTOR-CAR ROLLING STOCK).

On the Baltic Railroad, a small number of electric motor-car trains are used in which the traction motors are powered by storage batteries on nonelectrified sections of track.

On suburban railroads in the USSR, the most widely used electric motor-car trains are the ten-car ER2 and ER9P trains (see Table 1). In these trains, five of the cars are motorcars.

Table 1. Parameters of electric motor-car trains used in the USSR
	ER2	ER9P
Type of current ...............	DC	AC
Contact-system voltage (kilovolts) ...............	3	25
Motor-car weight (tons) ...............	54.6	59
Trailer-car weight (tons) ...............	38.3	37
Lead-car weight (tons) ...............	40.9	39
Car length (meters) ...............	19.6	19.6
Total power rating of traction motors (kilowatts) ...............	4,000	3,600

Each car of an ER2 or ER9P electric motor-car train has a mechanical section, electrical equipment, and pneumatic equipment. The mechanical section comprises an all-metal body, which functions as a single structure, and two welded undercarriages, each having two wheel pairs.

The electrical equipment includes DC traction motors (four in each motor car), current collectors, and transformers for supplying power to low-voltage auxiliary equipment, such as ventilation and lighting equipment. The electrical equipment of AC electric motor-car trains also includes power transformers and rectifiers for supplying power to the electric motors. A section of any electric motor-car train is equipped with devices for electric braking.

The pneumatic equipment includes compressors and tanks filled with compressed air. It is used for the braking system and for the automatic opening of doors.

For the motorman, each lead car is equipped with a cab containing the necessary monitoring and control equipment.

The modern electric motor-car train is a reliable, economical, and fast means of transportation. The electric power consumption is less than 40 watt-hours per ton-kilometer in special circumstances, that is, when large amounts of power are expended for acceleration and braking.

In the USSR, the ER200 electric motor-car train, which has a design speed of 200 km/hr, has been tested. The ER200 train consists of 14 cars, including 12 motor cars, and can carry 816 passengers. The power rating of its traction motors is 10,320 kilowatts. The train is equipped with an automatic control device that performs the functions of a motorman and with electric, magnetic, and electropneumatic disk brakes.

In Japan, an electric motor-car train with a speed of more than 200 km/hr is used.