EVM (train protection)

EVM is a train control system that is installed on all main lines of the Hungarian State Railways (MÁV).

The trackside part of the system consists of coded track circuits that work with a carrier frequency to transmit information. The carrier frequency is coded by an amplitude modulation of 100% with an electronic coding device. The data transmission between the coded track circuits and the on-board unit takes place via inductively coupled air coil antennas above the rails .

The data transfer from the line to the trains takes place through:

75 Hz carrier frequency
Amplitude modulated codes (100%)
7 codes (6 speed codes)

The driver is shown:

Cab signaling
Signal position: stop, permissible speed at the next signal (15 km / h, 40 km / h, 80 km / h, 120 km / h, MAX km / h),
no transmission / failure,
Maneuvering mode

The following is monitored:

Speed limit
Vigilance control every 1,550 m, if v _is <v _target ,
Vigilance control every 200 m, if v _is > v _target
Stop signal
Speed limit in maneuvering mode

The emergency brake is triggered

if the driver does not react
if the speed limit is exceeded after the alertness signal, or
if a stop signal is passed at more than 15 km / h
in maneuvering mode immediately after exceeding 40 km / h (in this case the brake is activated without any acoustic signal)

There are also additional functions:

Roll-away protection
Comfort function (display that the signal has moved to the running position when the train is stationary)

With regard to ETCS , EVM is managed as a Class B system (Class B system). A Specific Transmission Module (STM) exists for EVM .