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Putting the world's longest trams into service in Budapest

01 Apr 2006

Over the next year, BKV will take delivery of 40 low-floor trams from Siemens to operate the Grand Boulevard trunk routes in Budapest; at almost 54m in length, the six-section cars will be the longest trams in the world

Zoltán Donath
Director of Public Procurement & Investment, Budapest Transport Corp (BKV Rt)

LAST MONTH saw the arrival of two new trams in Budapest for commissioning trials. The first of 40 low-floor cars being built by Siemens, they are expected to enter service in July. BKV expects to have 20 vehicles in service by the end of this year, and the rest by mid-2007.

The cars are destined to operate Routes 4 and 6 along the Grand Boulevard, used by hundreds of thousands of passengers each day. Running from Moskva Tér to Móricz Zs K?€?rter via Nyugati Pú and Oktogon Place, this north-south line was Budapest's first tramway, and it remains the backbone of the capital's network. Connecting Pest and Buda, the route is carrying an average of 10000 passengers/h in each direction throughout the day, with packed trams typically following each other at 1min headways.

However, the existing rolling stock is no longer able to satisfy the growing demands of our passengers for improved comfort and shorter journey times, so BKV decided to order new trams with the latest technology, which meet current EU regulations.

A primary objective was to have a 100% low-floor design, to facilitate access by elderly people and mothers with babies and to speed up the boarding and alighting process. At the same time, we wanted clear and transparent passenger information systems, plus better heating and ventilation, whilst retaining an element of the traditional 'Budapest character'.

On April 23 2003, BKV Rt awarded a €150m contract to Siemens Transportation Systems and Kiepe Elektrik for supply of 40 Combino NF12B low-floor trams at a cost of €150m. These were to be nine-section cars, 54m in length, with capacity for 72 seated and 279 standing passengers. Appropriately, the busiest tram route in the world would get the longest trams in the world.

After the Combino cars operating in other countries began to develop structural faults, the contract was modified. Siemens is now building the vehicles as six-section GT12N cars, similar to the shorter GT8N version being built for the MST network in Portugal (MR05 p55), at a cost of €3&middot4m each. Assembly of the first cars began at the Siemens SGP plant in Wien during the autumn of 2005. The first vehicle was formally dispatched from the Austrian capital by Rail Cargo Austria on March 16.

Modular cars

The finished vehicle is 53&middot99m long and 2400mm wide, with capacity for 70 seated and no less than 353 standing passengers at 4 per m². Six of the seats fold down to provide space for wheelchairs, prams or extra standing passengers. This means that each vehicle will offer a 6% increase in capacity compared to the coupled set of Ganz cars that they will replace.

For rapid loading and unloading, there are eight doorways on each side, with large double-leaf swing-plug doors giving free passage for passengers with prams or wheelchairs. The internal floor height is 350mm above rail throughout the passenger area, sloping down slightly to the doorways where the boarding height is just 320mm.

The bodyshell is a self-supporting lightweight structure, assembled from prefabricated stainless-steel elements, with protection against twisting. The car end sections that transfer forces between modules and to or from the bogies are made from corrosion-resistant carbon steel, better able to absorb dynamic forces. The external wall panels are made from pre-painted aluminium sheets, which are glued to the load-bearing stainless-steel shell with flexible adhesive to permit rapid replacement in case of damage. The car ends which provide much of the vehicle's character are moulded from glass-reinforced plastic and bolted to the steel frame structure.

The air-conditioned cab is designed to meet the latest ergonomic requirements, with an unobstructed view in all directions. The windscreens have a high-performance demisting facility, and the large outside mirrors are heated and can be remotely controlled in all directions. The driver's seat can be adjusted in all the necessary directions, and a built-in vigilance system ensures that the drivers are constantly alert. A display screen in the cab relays text messages to the driver from the fault monitoring and diagnostics system, and advises on the appropriate action to be taken.

The comprehensive passenger information system includes large destination displays at each end of the vehicle, with two smaller displays on each side and six internal displays. Announcements can be made using a synthesised message system, or manually by the driver or traffic control centre. As well as the internal speakers, there are eight external speakers on the roof which can be used to broadcast messages to passengers waiting at the stops.

Each pair of car sections is permanently coupled using a steered Hübner articulation to form a single mechanical unit, allowing the formation of four-section vehicles for MST and the six-section versions for Budapest. The six bogies are mechanically identical, but only four are powered, with a Bo' 2' Bo' Bo' 2' Bo' wheel arrangement.

The GT12N bogie is derived from the Combino truck, with the ability to turn through up to 4&middot2í in curves. A triple suspension is provided, starting with rubber elements built into the resilient wheels. The second stage is formed from internally-mounted rubber spring pairs to support the stub axles. Finally, large semi-spherical spring elements on each side of the bogie support the bodyshell.

Each powered bogie incorporates two flexibly-mounted drive units. The eight 100 kW motors are longitudinally-positioned on each sides of the powered trucks, driving the two wheels on that side. This drive is expected to ensure a high ride quality and a low level of transverse oscillation.

The IGBT-based traction control package is highly modular, with a separate unit for each motor bogie. Each powered car section has a single roof-mounted container enclosing the control system, inverter and brake resistor.

Four independent brake systems are provided, with dynamic braking on the motor bogies and active hydraulic disc brakes on the trailer bogies, backed up by electromagnetic rail brakes on each bogie. For stabling purposes, there are passive hydraulic spring brakes on the driven bogies.

The containers for the heating and ventilation equipment are also roof-mounted, with the air flowing through ceiling ducts into the passenger saloon. As well as the powerful forced ventilation, each window has a sliding pane to the traditional Budapest design, with the exception of the four windows holding the information displays. Tinted glass is used to reflect heat during the summer. For winter operation, the pre-heated air supply is backed up by floor-mounted heaters at the doorways, primarily to prevent ice build-up beneath the low floor.

In preparation for the arrival of the new cars, BKV has been modernising the infrastructure to match. The depot which will maintain and service the new vehicles has been refurbished, and platforms at the various stops along the Grand Boulevard are being made more attractive.


  • CAPTION: Wide gangways between the car sections allow easy movement of passengers along the vehicle and provide plenty of standing space
  • CAPTION: Two of the 40 GT12N cars for Budapest take shape in the Siemens SGP plant in Wien
  • CAPTION: Running almost entirely on reserved tracks, the Grand Boulevard routes 4 and 6 are currently operated by 34 pairs of Graz GSM42 articulated cars, built in 1978, which will be replaced by the GT12N vehicles