The oldest regulators were made in 1972 and they are still in regular use on dieselhydraulic motor coaches. From today view, these devices are based on a museum technology (operating amplifiers made of single transistors, etc.).
Next series of speed regulators were produced in the half of 70's. They were used on electric and dieselelectric locomotives. The last serie based on analogue technology was produced during the 80's. These devices were used on relative modern electric vehicles, which have a powerfull rheostatic brake. The regulators have some auxilliary functions for better satisfying of drivers' needs, for example train - length checking or keyboard input of required speed.
The newest regulators are based on computer technology. Nowadays, 4 computer regulators are in regular use, the oldest one since March 1993. The processor is 8088 - type and we prepare a device with modern 80166 - type microprocessor.The advantage of computer - based device is lower price, better reliability and practically no maintenance.
All regulators can co-operate with any type of vehicle. The simpliest co-operation is with modern vehicles with analogue or digital input of required value of tractive/braking effort and electrically (pulse or analogue) controlled brake controller. But our regulators were used on almost all types of vehicles: on DC rheostatic controlled, DC thyrristor chopper controlled, AC with high-tension tap changer, AC with low-voltage thyrristor control, diesel vehicles with hydrodynamic transmission and diesel ones with electric transmission; on both track and shunting locomotives (here, continuous speed 0.25 km/h (+/- 10%) was necessary to have been achie- ved), on locomotives with maximum speed from 80 km/h (shunting locomo- tives) to 200 km/h (8400 kW express locomotive class CS 200 for Soviet railways) and also, automatic speed control device is used in Prague underground on Soviet coaches with rheostatic control. On track loco- motives, the precission +/-1 km/h is usual.
The speed - regulator is a very suitable device for radio control of shunting locomotives. Our department have realised this radio control on several types of shunting locomotives (AC, DC, Diesel). Now theese locomotives operate in shunting stations Nymburk, Kolin and Ceska Trebova.
In Prague underground, 36 vehicles (18 trains) operating on line C are equipped with automatic target braking device, the devices were mounted in 1978 and they are on analogue base. Except of target braking, some other functions are performed by this device, for example automatic switching the power off and on at the boundaries of electric sections, automatic opening the doors at the relevant side (left or right), automatic starting of tape-player with announcements for passangers, and others.
First experiments with automatic target braking on Czechoslovak railways were made in 1965. In the beginning of 1970's, the diesel - hydrodynamic motor coach class M 296.2 with automatic target braking was in daily use on 150 km - long route. This device included also the energy - saving part.
In next years, new devices for target braking were developped. Some of them were in use for relatively long time, but all these devices were not suitable for hard conditions of railway operation and maintenance.
In 1991, the first locomotive was equipped with the computer - based automatic target braking and energy saving device. The locomotive was a track universal DC type Nr. 163.034. In contrast to former devices, now the energy saving "device" is in real only a part of software, so as the target braking is another part. Both these softwares run in target braking computer.
The computer is an 8088 - type, we used the industrial computer kit of Czech firm MESIT. With central computer co-operates driver's terminal (with 8080), which performs a man - machine interfacing. The terminal also supervises a regular run of central computer.
The outputs of the target braking computer are connected to analogue speed regulator, which is a standard equipment of locomotives of this type.
Next vehicles equipped with computer technology were electric DC units class 470. Except of target braking computer (almost the same as the one on 163.034), new speed regulator (now as a part of software) and new computer central vehicle regulator were substituted for old analogue speed regulator and analogue central regulator. There are also new driver's terminals, with Z 80 microprocessor and also colour displays on one unit.
All the programs are written in assembly language of relevant processor and that is why the longest program (the complete program for automatic target braking) occupies only 12 kB of memory and it is quick enough to run on 8088 processor with 4.77 MHz clock.
The automatic target braking device increases the safety of railway traffic. Independently on driver, it automatically decreases the speed of the train before track speed limits (both permanent and temporary ones) or before signals in speed - limit position. At the target point, the speed mustn't be neither higher (it is an usual condition) nor lower than target speed, many similar devices allow the speed to fall under the target value.
Next, the device automatically stops the train before the signals in Stop position and at relevant stations and halts. From the time table stored in the memory the computer knows which stations are passed through and at which ones the train stops and also the regular arrivals in these stations.
If the train is late, the computer automatically tries to eliminate the delay (if the driver allows). On the other hand, when the train is in time, the computer tries to save the energy. It computes the necessar speed for achieving the nearest station or halt without using the traction (it means, only using drifting and braking) and when the real speed achieves this computed one, the computer automatically switches the traction motors off. This allows to save in average about 25 - 30 % of traction energy ("normal" train consisting of locomotive and coaches), the electric units save about 10 % of energy because of shorter scheduled running times. In some line sections, the device can save up to 80 % of energy.
In all former Eastern countries, including the Czech republic, the electricity and fuel are very expensive and so the energy saving devices have a great economic effect.
The computer reads from with train protection system the signal codes for cab signalling (line transmission). Since the cab signalling transmittes only 4 codes, we prepare radio transmission of signal signs.
For the track synchronisation, the magnetic information points are used. These points give only their addresses and no other information (like speeds, gradients, distances etc.) and that is why this system is very simple, cheap and reliable. All these informations are stored in on - board memory, in route map. The capacity of the computer memory (768 kB) allows to store datas of over 50 000 kilometers of single line track.
A special attention was payed to man - machine interface. Since the beginning of regular use in 1991, about 70 drivers changed at the driver's cab of the equipped locomotive 163.034. Many of these drivers told us their reminders to displayed picture or to way of control of the device and also told us their suggestions how to make these things so that they would better satisfy drivers' ideas. There were several steps while looking for the best picture.
Now we think we have found the optimum one.
The driver can see here: real time, the nearest station where the
train stops and regular arrival in this station, these informations
are useful especially at night, when the driver mustn't switch the
light in the cab on when looking in the time - table.
Next, he can see speed limit, which includes track speed limit,
train speed limit, speed limit set by driver, signal speed limit and
temporary track speed limit.
In the right half of the screen he can see real speed in analogue
and digital forms and the signal symbol. The design of the signal
corresponds with the real signals of Czech railways, which indicate
two speed limits, the limit at the nearest signal and the one at the
next signal.
In the lower half of the screen driver can see, for each branch,
target speed and target distance and also actual speed limit, if
exists. In the lower right corner, the status of the track - to
- train transmission of informations is displayed.
You really think, that there are too many informations on the screen and the driver is overloaded with watching them. But we should remind you
The drivers are fully satisfied with this picture, they vigorously refused to delete any of the displayed informations and they even want to show some more informations, like automatic drifting or the departure time. These reminders were accepted and at the units class 470 with newer devices, these informations are shown.