Railroad Automation and Remote Control

branch of engineering concerned with problems of controlling and ensuring safe movement of trains by automation and remote control. The basic technical elements of railroad automation and remote control are installations and devices for signaling, centralizing, and blocking; such installations and devices include block signaling, the electric staff system, centralization of switches and signals, devices for automation and remote control of gravity yards, automatic control of train traffic, centralized dispatching, and automatic dispatcher control of train traffic and barriers at railroad crossings.

The block signal system is the basic technical means for controlling and ensuring safety of train traffic on sections of track and at intermediate stations. The term “block signaling” means a traffic-organizing system whereby occupation of individual sections of track by trains is controlled by steady signals (lights or semaphores). When a steady signal is open (permissive), it authorizes a train to occupy the sector of track governed by it. Each section of track occupied by a train is blocked, that is, covered by a steady signal, which in this case assumes a closed (prohibiting) position. When a train is in a section of track the steady signal for the section is prevented from opening by switch devices of the block signaling system. These devices mechanically or electrically block the steady signal in its closed position until information comes into them that the section of track involved is clear. This information is in turn provided automatically because of the train’s action on the devices controlling its progress over the section of track: that is, each protected section of track can have only one train on it. Such devices can in general be operated either manually (semiautomatic block system) or automatically (automatic block system). These systems are used both for one-way and two-way traffic.

The electric staff system is used as a rule to control the progress of trains over stretches of track intended for twoway traffic. The authority to pass over a stretch of track in this system is indicated by the staff for the given stretch of track being in the possession of the engineer.

Devices for centralized switches and signals are the main engineering devices for controlling and ensuring safety of train movement within the limits of railroad stations. These devices make it possible to operate switches and signals from a single point—the centralized control post. Depending on the type of energy used to move the switches from one position to another, a distinction is made between mechanical centralization with the use of human muscle power to change switches and signals, mechanical centralization with the use of hydraulic or electropneumatic devices for the same purposes, and electrical centralization utilizing electrical driving units to move switches and semaphore arms and corresponding electrical circuits to switch on semaphore signal lights.

Gravity yards use automation and remote control equipment to increase the work capacity of the yards. This equipment includes devices for controlling the speed of separated cars and devices for automatic centralization of control of the switches. Devices for automatically determining the speed at which cars are released can also be installed. All these devices operate in combination with equipment for automatic remote control of yard locomotives.

There are automatic devices for controlling train traffic over a railroad sector (automatic dispatcher), for controlling the operating cycle of every train in accord with a traffic schedule (automatic engineer), and for ensuring that a train reduces speed when it approaches obstacles (automatic safety control). All modern systems for reducing the speed of trains as they near an obstacle (a closed track signal, another train, a break in the track) operate in conjunction with automatic locomotive signal devices that automatically relay information on track signals or the state of the track sector ahead to the control cab of the locomotive. The combination of automatic locomotive signal devices and devices for automatically ensuring reduction in train speeds is called automatic train control.

Centralized dispatching is a combination of electrical centralization and automatic block devices. With centralized dispatching, control of switches and signals of individual points of the entire railroad sector is concentrated in the train dispatcher, and train traffic over sections of track is controlled by an automatic block system. Dispatcher control of train traffic uses systems that automatically provide the sector train dispatcher with data on train traffic on the sector, the position of entry and exit light signals, and the condition of sectors being left or entered (free or occupied) at intermediate stations. The location of trains and the state of tracks and light signals is shown on a light panel mounted at the dispatcher’s post.

Restricting devices for closing off crossings constitute a complex of instruments and equipment installed at vehicular grade crossings. These devices are automatically controlled by the moving train and block motor-vehicle traffic over the railroad crossing when a train approaches.

The systems, of railroad automation and remote control increase the safety of train traffic and the handling capacity of railroad lines, assure better use of rolling stock, and further the attainment of higher indexes for rail transportation.

Research projects on optical railroad signaling and interval control of train traffic and on the theory of electrical rail circuits and basic types of apparatus, as well as research in the economic efficiency of use of railroad automation and remote control equipment in various operating conditions, are currently under way for the further improvement of rail-road automation and remote control.