NOVELTIES ON METRO LINE M4

Handed over on 28 March by Viktor Orbán and István Tarlós, Metro Line M4 has introduced a number of technical innovations, which are different from the other lines. Among others, the internal shaping of spaces, the ventilation and the passenger information display, full accessibility on the entire line, and the automatic train control and monitoring are quite different from the other lines. Following the handover, passengers could use the line free of charge over the weekend, and experts have already assessed the experiences of the opening weekend.

The train control, power supply and communications systems of the new line enable the M4 trains to run in fully automatic, driverless mode. With the help of the telecommunications systems, the Traffic Control Centre and the controllers at the stations can monitor and control passenger flow and the mechanical equipment of the stations. During the half-a-year Test in Traffic Operation, which can be prolonged, a train attendant will be on board each train for the sake of maximum safety, but the driver compartments will be removed from the two ends of the trains at the end of this period. According to international experience, automatic train control metro lines ensure greater safety for passengers than traditional manned trains.

The track areas by the platforms are continually scanned by a radar protection system with 30-cm sensing sections. Should any object larger than 30 centimetres or a person fall into the track area, the power-supply system automatically shuts down, and the sensor system immediately issues a command for emergency braking by the train. The passenger protection radar fully substitutes for the emergency push buttons installed on the platforms of the earlier metros, and, by minimizing intervention time, it clearly increases safety.

The LED light stripes along each station platform clearly mark off and highlight the platform-edge safety strips. In all the stations of the line, these light stripes, being coloured different, also show the direction of the trains coming into the stations. The orange light stripe by the right-hand track marks the direction from Kelenföld Railway Station to Keleti Railway Station; while the blue light stripe by the left-hand track marks the direction from Keleti Railway Station towards Kelenföld Railway Station. The light stripes begin to flash a few seconds before a train approaches the station, which is helpful for those hard of hearing. The closing of the doors is signalled by a special warning sound, which is particularly significant in order to ensure the safety of passengers and uphold the schedule in the case of an automatic metro, because, after the sound goes off, boarding must not be attempted any more; otherwise train attendants will have to intervene.

Moreover, cameras placed in all stations and trains assist the work of the dispatchers and controllers, enabling them to immediately intervene should a technical failure, the danger of an accident or personal injury occur.

The new passenger information display is a state-of-the-art system. The passenger areas have a loud-speaker system capable of live-speech and pre-recorded announcements, and can be activated sectorally. The arrival times of trains are shown on separate display units as per direction. The dynamic display units at the platforms are capable of providing any current information to the passengers.

All stations of Metro Line M4 are accessible due to the lifts installed. For blind and sight-impaired passengers, so-called ATS equipment was installed into the sides of the escalators, which lets them know whether the escalator is moving up or down. Tactile stripes aid blind and sight-impaired passengers, too, which are built into the line at much greater frequency than usual; their ribbing protrudes form the floor and can be felt by feet, as well. Brightly coloured stripes mark the edges of steps in stairways and escalators.

Stations with one exit have four flights of escalators, while those with two exits have three flights each . In the event of operation failure or maintenance, flights being repaired will thus not cause bottlenecks.

The architectural design of Metro Line M4 had a clear intent of enabling sunlight to reach down to the platform areas wherever it was technically possible. At Bikás park station and Keleti Railway Station, natural light passes directly down to the platform area through the windows of the structure; natural light reaches parts of the escalator areas at Móricz Zsigmond körtér and Fővám tér, while it illuminates the subway area at II. János Pál pápa tér. At Rákóczi tér, natural light reaches to the landing of the escalators at platform level through a special light conveying equipment. The special equipment is programmed to follow the movement of the Sun; mirrors fixed on pillars at the surface reflect light to the secondary, fixed mirrors set above the pool in the square, which then cast the sunlight down to platform level through two tubes. The tubes are kept mist and dust free by way of a filtering pressure ventilation equipment. After sun dawn, lamps attached to the upper ends of the tubes provide lighting in the dark.

For the artificial lighting of the stations, modern-day LED-based lamp fixtures are used. The lifespan of these lights are much longer than any usual bulb, and their volume of electricity consumption is also far more advantageous. The internal design of the stations enabled and necessitated the use of decorative lighting appliances, which provide a more aesthetic and thus more attractive metro environment for passengers.

Another element of the architectural concept was not to line the large load-bearing structures of the stations, and so they were made with aesthetic fair-faced concrete with no stone or metal coverage. The side walls at most stations have artistic facings and sculptured artworks on them, which, apart from the signboards, also assist passengers in easily identifying stations.

Air pollution at the stations is also continually monitored by special equipment, which automatically turns on the main ventilation systems, bringing fresh air into the passenger spaces, and it also keeps station temperatures between +5°C and +27°C.

The problem of strong draught, which has often prompted complaints on other lines, was remedied on Metro Line M4 by building ventilation shafts before and after stations so that draught accumulating before trains coming in is deflected right up to the surface and the suction effect after trains going out is also decreased.

In order to be prepared for fires, modern-day fire-extinguishing and evacuation equipment was installed, which enables extinguishing both on the trains and in the stations, as well as the safe evacuation of passengers. The heat and smoke deflection ventilation system capable of moving 1 million m3 metres of air per hour per station was designed so as to direct fresh air from outside into the space from where smoke has been deflected and thus to ensure that evacuation routes, including the escalators, are smoke free. Stations less deep can keep evacuation routes smoke free for up to 20 minutes, while deeper stations up to 30 minutes. Automatic extinguishers receive trains that might have caught fire in the tunnel, and begin extinguishing before the fire brigade arrives. Smoke deflection from above the trains is ensured by the so-called smoke screens hanging down above the platforms. In the running tunnels, steel evacuation walkways were built left of the direction of travel, on which – in the event of fire or a train becoming immobile for some other reason – passengers can walk to the next cross passage, one of which was built every 300 metres, and evacuate into the other tunnel. In such an event, traction power supply is of course cut in the undamaged tunnel, as well.

The metro line handed over by the prime minister and the mayor on 28 March could be used by the public free of charge over the weekend. The experiences of the opening weekend have already been summed up and assessed: due to the huge interest and overload, there were a few slight hitches in the schedule, the operation of lifts and escalators, but these were and are handled in the framework of the on-going Test in Traffic Operation by experts.