Streetcars from Stadler

Stadler is a mid-range supplier for modular and tailor made rail vehicles. The customer and their specific requirements are a clear priority for Stadler. This commitment to customer satisfaction is expressed in the company’s motto “Geht nicht gibt es nicht!” (“Impossible is not an option”).

Stadler has answered the growing worldwide interest in developing effective urban public transport systems by developing the Variobahn and Tango tram families. The Variobahn (built under licence from BT) is of modular design, and can be supplied in 100% or 70% low-floor versions. The basic design can be easily varied according to customised requirements with regard to overall Iength, body shell width, track gauge and operating voltage. Both uni- and bi-directional versions are available; multiple-voltage and dual traction (electro-diesel) specifications can also be met.

Stadler’s modularity is demonstrated once again in the ability to produce the Variobahn’s body shells in widths from 2.3 to 2.65m (some tramway systems thread through very narrow streets!) and overall vehicle lengths ranging from 21 to 43m, with varying numbers of sections (thus catering, for example, to differing volumes of traffic on diverse routes). Gauges between 1,000 and 1,435mm can easily be accommodated in the design; and due to modern driveline technology, producing bogies and wheel sets for other gauges is no problem at all for Stadler.

The new street car Tango

Similarly, the Tango range of trams offers comparable potential for customers, including a wide range of gauge, length, width and traction variables. However, the Tango is designed to offer a broad spectrum of floor options ranging from 70% low-floor to 100% high-floor.

Stadlers streetcar design

The streetcar design is based on the most variations possible in a full spectrum of parameters with clearly defined mechanical and electrical interfaces for all components and systems. Clear emphasis is placed on the use of tried and tested technology to ensure utmost reliability. Before any components or systems employing new technology are incorporated into a design, exhaustive testing is carried out as part of the design development process to be certain that their performance meets both the customer’s and the manufacturer’s expectations.

Body shells

The body shell structure is designed to serve as a supporting framework for the vehicle, incorporating the use of long-life high alloy steel. Measurements derived from tests on existing vehicles are used for dynamic testing purposes on new vehicles’ body shells, thus making it possible to ascertain in advance the parameters proportional to operating stability and fatigue strength. It is thus possible to incorporate further criteria in addition to the EN 12663 and VDV153 standards when designing body shells. Designs able to withstand pressures of between 200 and 600kN are available. To allow for the highest possible design flexibility, front and side panels are made of glass-fibre reinforced compounds, a technique allowing for almost any kind of sculpturing of the front-end and sides of the body according to the customer’s aesthetic preferences. The panels are produced in easily-handled sizes, and are affixed to the body shell framework using long-life adhesives; this results in a high quality surface finish, and also enables individual panels to be quickly replaced should they become damaged. Panels are of different sizes depending on whether they are fixed to the ends or sides.

Interior Design

The decision that the passenger areas should be free of equipment cabinets was made in the design stage. The interior can be custom designed to cater to the customer’s preferences; for example, the amount of space allotted to seating, to standing areas and to multi-purpose spaces. The latter can be designed to accommodate prams, wheelchairs and bicycles. Fresh air ventilation is provided by means of two ducts running through the space between the ceiling and the roof. Warm air heating is fed into the passenger spaces at floor level and air-conditioning is an optional installation. Either a single or double lighting strip can be fitted into the ceiling panels, between the ventilation ducts.

Control and communication systems

These control all processes which take place in the tram, sending data on incidents and the system status in a separate monitor having diagnostic ability. This makes certain that a comprehensive, detailed overview of the vehicle’s performance and status is available at all times. The communication network consists of a CAN Open vehicle bus. This links the main on-board subsystems both with each other and with the vehicle control centre. Data can either be transferred at regular intervals or whenever specific incidents occur. A WTB train bus is also available, linking trams operating in multiple traction.

Some subsystems, such as those operating text panels and public address announcements, are provided with their own additional bus systems which are not connected to other vehicles buses. Those systems and components without a vehicle bus connection are linked via input/output modules to the control and communication system.

Couplings

The couplings are located within a front-end bumper bar spanning the entire width of the vehicle. This is linked to the body shell via two reverse-acting hydraulic dampers in order to minimise damage in the event of an end-on impact. The coupling links between vehicle segments incorporate toothed ball bearings to absorb the relative movements of each segment, and to transfer acceleration and braking forces. The gangways between segments are 1600mm wide, thus facilitating an open view the entire length of the vehicle. Gangway connections have a solid inner lining which provides a high level of noise absorption.

Entrance doors are of double and single leaf types, 1300mm and 800mm wide respectively. They are equipped with operating mechanism monitors and light sensors, as well as primary and secondary closing edge monitors, ensuring that neither passengers nor their belongings are trapped in the closing doors.

Driveline

The driveline is comprised of a modern DC-AC converter with a direct U-converter on the pantograph. Having passed through the LC input filter, the line voltages form the DC intermediate circuit inside the vehicle – in this way the line voltage is converted only once. This makes for a very efficient system since the number of components involved is reduced to a minimum which results in weight savings, easier installation, and a less complex operation. The DC intermediate circuit feeds three-phase variable- voltage and variable-frequency converters fitted with IGBT power semi-conductors.

Each segment of the tram has its own set of independent converters which each feed the two traction motors on each bogie; these motors are installed parallel. There are therefore two driveline systems per tram ensuring optimum acceleration and adhesion characteristics. This driveline arrangement certifies that should one driveline unit fail, the other can increase its power output by 50%, thus minimising the risk of a tram failing completely while in service.

Traction converter

Two mutually independent Bordline-CC800 converters are provided on all models of Stadler trams. These supply the AC current as required with a variable voltage and frequency to control the traction motors. Each converter is designed to supply either two transversely-mounted asynchronous or four hub-mounted motors on each powered bogie. All power control system components are EMC-compatible. Converter components are compact and robust, designed specifically for use on rail vehicles.

Each converter is comprised of a DC circuit, a traction converter, a brake chopper, an auxiliary drive converter, and a battery charger. Heat build-up in the converter is reduced by way of a water-cooled system. Water temperature on water-cooled Variobahn motors is lowered by use of an external heat-exchanger. The same type of converter is installed in both low-floor and high-floor tram models, and can either be mounted beneath the floor or at roof level.

Traction motor types

The 100% low-floor Variobahn version is powered by asynchronous, gearless, hub-mounted, water-cooled 45kW motors. In the 70% low-floor versions of the Variobahn and the Tango, as well as in the 100% high-floors models, two air-cooled asynchronous motors of between 105 and 125kW are mounted transversely in each bogie.

Bogies and bogie assemblies

The use of hub-mounted motors makes possible the compact bogie design used on Variobahn low-floor vehicles. It was necessary to extensively revise and optimise the basic design of the bogie assembly frame and wheel guides, making allowance for the higher load factor which applies in the case of low-floor vehicles. Measurements were made on existing systems of this type, and extensive dynamic tests were conduced, so that the end product and its component parts would have both a long lifespan and high reliability. Customers can choose between two secondary suspension systems – either conventional steel springs, or pneumatic springing – the latter offering a softer ride. In both cases primary suspension is by way of a multi-layer rubber spring, mounted on the wheel guides.

In the case of the suite of Tango trams, bogie design is based on a more conventional arrangement, with the two traction motors mounted transversely. These transmit their power via a multi-stage transmission system to the fully-cushioned drive gears. Bogie and body shell are connected via a toothed ball bearing.

Braking systems

The fundamental braking system is electro-hydraulic. Braking force is provided by hydro-compact devices that link the hydraulic pump and regulation valves within a single housing and are mounted inside the bogie assembly on which they act. They are connected to the body shell, are provided with electrical control lines, and they activate the compact brake shoes on the wheels via short hydraulic lines through the bogies.

Braking is computer-controlled with the support of a micro-controller and all braking processes incorporate anti-slip functions. The vehicle control and communication system makes certain that braking force is always optimally applied. Should the compact devices fail – a very rare eventuality – all brakes can be released via an emergency control, and there is no limit to the number of occasions this option can be used. Special auxiliary equipment is proved to enable this.

Air-conditioning

Both models of tram feature compact air-conditioning and heating units. Warm air circulators are fitted in areas where cold air is most likely to penetrate – around the doors and in the gangways between the articulated segments. The required temperature in passenger areas is governed by a central controller and regulator. The air is drawn in from outside and channelled into the passenger areas and remains at outside temperature, or is either heated or cooled, depending on the necessary comfort level. To minimise noise from the ventilation system, all intakes are fitted with sound absorbers. The external air flaps are electrically controlled and can operate in two ways, either by recirculating inside air, or by drawing fresh air in from outside.

Stadler trams for Switzerland and Germany

For optimal cooperation with our customer and a higher degree of flexibility, Stadler builds its streetcars in various locations. Those for Germany are built in Berlin by Stadler Pankow and the vehicles for Basel are constructed in Altenrhein, Switzerland. The competence centre for streetcars is Berlin.

Dancing Tango in Basel

With the acceptance of the outline contract in May 2006, Stadler will deliver 60 Tango trams over the next 10 years for service in the region of Basel for Baselland Transport AG (BLT) and the Basler Verkehrsbetriebe (BVB), Switzerland. The initial four vehicles will be delivered in 2008 and after successful trial operations, the 1st series of 15 vehicles for the BLT and 15-25 for the BVB will be delivered. The 2nd series of 20-30 vehicles should be delivered in the year 2014. The Tango has a meter wide track gauge and a 75% low-floor area. The vehicle is 45m long and offers a place for 276 passengers, 94 of which can be seated.

The over-all Tango design concept meets the demanding conditions of the BVB/BLT lines with their narrow curve radii, twists and turns in the tracks; and these characteristics combined with the careful consideration of passenger comfort, operational safety and maintenance-friendliness. In this way the proven components of the Stadler product family are put to use. Some examples of this are the following:

• The motor bogie is based on the proven vehicle models used by Forchbahn and Trogenerbahn
• the trailer bogie is based on the GTW mid-section of the meter gauge
• the control and communication system comes from the GTW and FLIRT.

The new Basel tram is a uni-directional version with just one driver’s cab. It has a width of 2.3 meters. The articulated-joint construction enables an optimal utilisation of the combined BVB/BLT structure gauge.

The concentration of electrical equipment is contained in boxes on the roof of the vehicle as well as in cabinets in the driver’s cab. In this way, the passenger areas are free of additional apparatus-cabinets and can be put to more generous and flexible use otherwise.

The vehicle is designed with a life expectancy of 40 years. All vehicle and equipment parts are manufactured of rustproof or corrosion resistant materials.

The front-end encasement elements are based on the newly developed design by Stadler Rail. Important elements in that design are a timeless and attractive form, maximum functionality with regards to passive safety (pedestrian protection), standard post-accident repair options as well as optimal visibility of the line signals.

Passenger friendliness

The new tram enjoys a notable increase in comfort when compared to present vehicles, namely:

• Larger capacity (276 places) compared to the conventional BLT vehicles and provides more space and noticeable relief, particularly during rush hours
• The tram is 75% low-floor and has a barrier-free interior. The walk-through tram allows for more spaciousness and better public supervision
• The eight expansive double-panel passenger doors are well placed in the low-flow area. This facilitates a rapid passenger exchange and offers those passengers with impaired mobility as well as parents with children’s pushchairs easier access to the vehicle. The second door from the front is additionally equipped with a retractable ramp for wheelchair users
• There is an additional 4 cm of space between the seats in these as compared to the trams that have already been in operation in Basel; this provides greater legroom which is an important factor in a society in which people are consistently taller
• Air-suspension and bogie engineering with greater primary and secondary spring make for a more comfortable journey
• The vehicle is air-conditioned and well ventilated. The room temperature is comfortable and a dehumidifier keeps the windows from fogging up and therefore allows for unimpeded visibility in the passenger areas
• The entire vehicle monitored by a video surveillance system. The rear third of the passenger area is separated by a glass wall which is installed with late evening travel in mind. This both prevents vandalism and raises the passenger’s sense of safety
• The tram is easily cleaned
• The vehicle is equipped with a modern, contemporary information system.

Profitability

In addition to the above named qualities, the other deciding factor in favour of the Tango for the two Basel transport companies was profitability.

Two central criteria which strongly influence the profitability are the maintenance costs for the tram as well as the effects of the vehicle on the attrition of the track infrastructure. As a rule of thumb, the full maintenance costs over the lifespan of a tram generation are approximately equal to the procurement price.

The Tango vehicle is based on proven and classical bogie engineering. The wheels have a greater diameter than the 100% low-floor vehicles. The vehicle weight is distributed over ten axles rather than eight. This leads to a lower axle load and therefore less attrition of the track infrastructure. Also, due to simpler engineering, the maintenance costs on the vehicle are lower.

The potential for an additional 10% transport capacity per tram helps ease the expensive peak loads during rush hours. The existing infrastructure is put to better use and productivity rises. The vehicle is equipped with energy saving drive technology; the braking current flows back into the network or can be used by others.

Minimising risk for the client

Another important factor for both the Basel transport companies was to minimise risk after the experience with the Combino redevelopment. For one thing, the strict definition of the supplier’s eligibility criteria only allowed those with proven experience in the construction of metre gauge and multi-articulated vehicles to undertake a project of this size. Together with the BLT/BVB procurement team, additional consulting engineers will oversee and inspect the detail design-engineering work and the various calculation steps at the manufacturer, Stadler, during the order processing phase.

In addition, a procurement concept will be chosen which provid for the pre-delivery of four vehicles (two of which are being build with test equipment). These will be tested and proven throughout the space of two full fiscal years. Only at the point that the specifically defined properties will be confirmed will the customer be committed to purchasing 15 vehicles. The use of proven system components from the existing Stadler product family also guaranteed a higher level of product reliability.

Stadler’s streetcars in Germany

Stadler Pankow is presently building 30 Variobahn streetcars and 6 Tangos for Bochu-Gelsenkirchener Strassenbahn AG (Bogestra). Bogestra is one of the largest urban operators in all of Germany with a network of around 100km. The Tangos will be deployed on the Bochum-Heren route while the Variobahns are used on the metre gauge interurban routes. The Variobahn will be bi-directional with a 100% low-floor 350mm above rail level, air conditioning, and ramps for disabled passengers. The Tangos will be 100% high-floor and bi-directional, with folding ramps for the handicapped, as well as a transparent partition behind the driver’s cab. Both Variobahns and Tangos will be commissioned during 2007.

Stadler will be delivering six 5-section Variobahns in 2007 for Verkehrsaktiengesellschaft Nürnberg (Nuremberg) VAG. The Nürnberg-Fürther-Strassenbahn-Gesellschaft started operation in 1835 as the very first operator in Germany. Nuremberg had horse-drawn tram service from 1881 to 1898, when the network was electrified. VAG’s Variobahn will be 100% low-floor models, with a floor height of 350mm. They will have slim 2.3m wide bodyshells and be equipped with air suspension.

The Münchner Verkehrsgesellschaft (MVG) operates bus, metro services and trams and has ordered 3 Variobahns with an option to buy an additional 19. These will be uni-directional vehicles, 100% low-floor with a floor height of 350mm. Air-suspension will be fitted. One vehicle will also be provided with an on-board power storage system, enabling it to traverse the famous English Garden park (Der Englische Garten). In this section of the line there is no catenary for aesthetic reasons.