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KÖLN (Cologne): low-floor success boosts system expansion

KVB is considering mass conversion of high-platform routes, and a vast new fleet of vehicles is on order. C. J. Wansbeek explains why morale is so high.

A distinguished cradle of creative formulae for urban rail. In the year 2002, this honour is well deserved by the city of Köln, now that KVB, the transport operator, has just celebrated its 125th birthday. Köln or Cologne, the sparkling metropolis. The liveliest of all German cities, with its Carnival, each year in February, the biggest in the country. From miles away, the spires of the massive Köln cathedral can be recognised. The inner city, with thousands of stores and boutiques, is on the left bank of the Rhine. Life is sweet in this city, where rail transport abounds, with new lines being built, and others in an advanced planning stage.

The final incarnation of the Stadtbahn-B design saw single-ended but double-sided cars that operate coupled back-to-back, saving two driving positions. This view is at Barbarossa Platz. (M. J. Russell

Ten different light rail routes, all standard gauge, cross the river over impressive bridges (there is no cross-river subway). In the background, one sees a continuous flow of DB trains, and S-Bahn trains (frequent regional trains over dedicated railway tracks), as well as TGV trains to Paris, and equally-fast German-built ICE trains to domestic destinations such as Frankfurt, the latter city reached from Köln within an hour over 177 km of new high-speed tracks, inaugurated in 2002. Few cities in the world can match Köln in terms of completeness of rail networks.

With a population approaching one million, the greater Köln area makes up the leading city of North Rhine-Westphalia, the largest Bundesland (province). Over 20 million people live within a radius of one hour by fast train from Köln. The Rhine-Ruhr region is leading in industry, arts, museums, telecommunications, science and research. Since times immemorial, Köln has been a traffic junction. It was a key intersection of trade roads of the Roman Empire. As a member of the Hanseatic trading league, it was the ruler of medieval trade routes. Since 1360, Köln has organised trade fairs. At this crossroads of long-distance rail routes, 1 200 trains arrive each day under the steel-and-glass canopy roof of the Hauptbahnhof, or main railway station. 10 European motorways intersect with the motorway ring road around the city.

A coupled set of early 1970s eight-axle Düwag trams on route 12 at Weyerstrasse Weg. (M. J. Russell

Köln has a long tradition of enthusiastic rail planning, always hand-in-hand with appropriate investments. There is a strong political will. Public transport is the lifeline of Köln's economy, with rail traffic as the cornerstone. Tens of thousands of commuters with jobs at Köln have to travel long distances between their homes and their city jobs. This has stimulated much new light rail construction, with more to follow.

The tramway and light rail network of Köln and Bonn, with the 2001 system in red, the planned extensions in green and the possible future extensions in yellow. If all were realised the 247-km network would increase to 346 km. (KVB

The 1960s were the watershed for Köln. By that time, WW II damage had been repaired, and the 15-odd city tram routes were running again. There were a half a dozen suburban tramlines as well, with distinct rolling stock. Two parallel interurban electric lines, operated by the independent company KBE, linked Köln with the city of Bonn, 25 km to the south. The city of Bonn possessed its own tramway. Linked to the Bonn and Köln systems were various independent rural tramways.

There was fragmentation in operations, with so many companies. In those years, urban transport followed the classic tram recipe. This meant city trams (motor trams, short trailers), with primitive stops in the middle of streets. Passengers had to cross streets and clamber aboard the tram. Trams were not-too-fast, and increasingly, trams were blocked by increasing motor traffic. Many turning loops were oversized, often with an abundance of parallel tracks, a space-consuming oddity in a fast-growing city, in need of new land.

The breakthrough came with a new transport concept, in the early 1960s, stating: 'we will refrain from building a heavy metro. Instead, our dense network of trams will be preserved, and will be gradually improved to become a Stadtbahn, supertrams, with stepless entrance, with all platforms at the same level as the vehicle's floor, 900 mm above street level, with inner-city tunnel segments, and with a full integration of city, suburban and interurban tram systems in both Köln and Bonn'.

Together with Bonn, Köln became Germany's first city to adopt a Stadtbahn concept. Other German cities followed, inspired by this example. The city fathers who signed the basic policy document of the 1960s were aware that none of them would live long enough to witness the full completion of their Stadtbahn vision. But switches were set in a clear direction, and today, the Stadtbahn concept is valid as ever.

Since the 1960s, transport companies have merged, and rail systems were unified, although a full corporate merger of the Köln and Bonn undertakings is not expected before 2003. Nevertheless, at operating levels, co-operation is already very close. The case of the north-south Stadtbahn route 16 is famous. It was one of the first palpable results. Brand new rolling stock, of identical design, a number of Stadtbahn-B cars in Köln livery, others in Bonn livery, level boarding over all the line, on reservation on most of its length, the result of a merger of former city tramways in Köln and Bonn, and in between a former interurban line of the KBE, all these stretches rebuilt and glued together into one 30-km long service, marked by high speeds, smooth riding comfort, and short intervals.

The first of the K5000 Stadtbahn cars, 5101, at Melatengürtel, during the 125th anniversary celebrations on 25 May 2002. (M. J. Russell

Route 16 starts in the northeast of Köln, where it uses a 1997-built 1.3-km subway (also used by routes 13 and 15), to reach Mülheim for convenient interchange under one roof with S-Bahn lines S6 and S11, connecting with Düsseldorf, Essen and many other cities. Beyond Mülheim, the 16, on its way south rises to spectacular heights on the tram reservation in the median strip of the Mülheim Bridge across the river Rhein. After running over surface tram tracks, route 16 dives into a 1970s-built tram subway to reach central Köln, including the main railway station. After that it surfaces again, continues over the tracks of a former interurban line to reach central Bonn, from where it continues over tram tracks as well as through a 1980s-built Stadtbahn subway. For the passenger, it is just one long smooth ride.

Since 1978, route 16 has been the backbone of city transport. After the 16, other classic tram routes were upgraded one-by-one, by adding subway segments, and by introducing new rolling stock. The Stadtbahn is now a full light metro system, using tunnels and surface tracks on reservation, over which fast service by coupled vehicles is achieved.

An interesting feature is that Köln rejects the idea of introducing of coupled sets of three Stadtbahn cars, because traffic is evenly spread over the entire city area. So all stations were designed with a maximum length to accommodate sets of two coupled cars. Through the inner-city subways, headways of only 72 seconds are commonplace, which equals a capacity of 20 000 passengers per direction per hour. Today, the inner-city tunnels make up a full network of 34 km, including connecting surface lines. This complete system was realised at much lower costs than a heavy metro would have required. A EUR 600 million project has been agreed for a second north-south subway under the city centre by 2008, to relieve overcrowding on the existing alignment,

Köln was closely involved in the development and design of the Stadtbahn-B cars. A total of 167 were delivered between1976 and 1996 by Düwag and Waggon Union (just 10 cars at a time when KVB was trying-out dual-sourcing). The Stadtbahn-B, with floor level 900-mm above streets, inspired a number of Ruhr area cities, as well as Düsseldorf, to order similar vehicles, and professionals regard these as one of the finest LRVs ever built. Altogether, some 500 Köln-inspired vehicles of this breed were built in the 1970s and 1980s. As the upgrading process took much time, the Köln tunnel sections had to be used also by a fleet of older, 8-axle Düwag trams, adapted for service on 90 cm high-platform tunnel sections. So, the term 'Kölner Mischbetrieb' (mixed operation Köln-style) relates to the sharing of the same tracks by Stadtbahn cars and 8-axle classic trams.

The Stadtbahn-B cars are numbered in the 2000-series. The 8-axle trams in the 3000-series, with 108 units built for Köln between 1963 and 1969. At present, some a total of 49 eight-axle trams remain in service (on routes 5, 6, 12), and mixed operation will continue until 2006. The phasing out of the 8-axle trams will bring an end to all turning loops, as all remaining cars will be double-ended, as outlined by the original Stadtbahn concept. 40 eight-axle trams (formerly belonging to the Köln 3100-3200 series) are now in service on the tram network at Konya, in south-east Turkey. This system has a length of 18 km, is scheduled to grow to 34 km, and negotiations are going on to export another 48 8-axle trams to Konya, from the 3700-3800 series.

The future division between the low (dotted line) and high (solid line) floor networks in Köln. A casualty is the Ubierring-Marienburg section of route 6. (Köln-Stadt

The success of the ex-Köln trams at Konya has inspired the Turkish Government at Ankara to embark on a pro-light rail policy, adopted by 1998, with Government support for the many new tram lines being planned and built all over Turkey. One Turkish city, Bursa, ordered a turnkey high-floor Stadtbahn-type network, including matching Siemens LRVs, modelled on the high-floor Stadtbahn concept of Köln. The first stretch at Bursa was inaugurated in mid-2002. As far as KVB is concerned, it does not engaging in foreign consultancy activities of any sort. It feels it should focus on its home.

Another form of mixed service seen at Köln concerns the use of tramlines for goods transport. This still takes place over Stadtbahn tracks between Köln and Bonn, and on a section of tramline near the Ford factory in north Cologne. Other Köln tramlines, such as a stretch of route 2 near Frechen, are no longer used by freight trains.

The Stadtbahn led to a surge in ridership. In 2001, KVB carried 234 million passengers. Between 1986 and 2001, the number of passengers of KVB, Kölner Verkehrsbetriebe, rose by 42%. Growth is unstoppable; each year sees more passengers, one record after another broken. KVB is probably the fastest-growing undertaking European light rail operator. Only 10% of the population never make use of any of KVB's services, a survey found, so KVB regards 90% of the local population as its clients. The city of Köln through its annual surveys discovered that the part of the population who prefer to take the Stadtbahn for their inner city shopping on Saturday has gone up from 40% to 60% over the last five years. The 40-odd bus routes, all feeder lines for the rail system, are kept in the background by KVB.

This huge traffic explains the willingness of local leaders to invest in new rail. The Stadbahn is growing much faster then suggested in this magazine, in its issue of April 1999, when the impression was that the system was more ore less complete, with the exception of the second north-south tunnel. But traffic has soared since, and so has willingness to pay for it. For a few years, the city government is dominated by the conservative CDU, often quite unenthusiastic about light rail, but the merits of the Stadtbahn (with an average commercial speed of 26.3 km/h among the best in Germany) are such that the CDU councillors continue to approve new investments. In 2001, KVB reached an impressive cost recovery rate of 69.3%, with operating losses amounting to an acceptable EUR 90 million per year.

The future second north-south subway to relieve the existing overloaded section between Dom/Hbf and Neumarkt. This will be used by routes 5 and 16, and a new route 17 (Reichensperger Platz-Arnoldshöhe), replacing bus route 132. (Stadt Köln

Against this background, extensions are welcome. These include:

A second north-south subway
The 4-km long second north-south Stadtbahn tunnel will comprise six new underground stations (Rathaus, Heumarkt, Severinstraße, Kartäuserhof, Chlodwigplatz, Bonner Wall, and one street-level station (Markstraße). The existing Breslauer Platz underground station will be completely rebuilt with flying junctions, and under one single roof a very convenient interchange to a number of S-Bahn lines. This will require a fourth-month closure of the existing subway between Dom/Hbf and Breslauer Platz in 2004, with extensive diversions. The subway will probably be used by high-floor north-south lines 5 and 16 and a new route 17, with the 5 and 17 continuing south of the Ring on new surface alignment to Arnoldshöhe. Actual construction of the tunnel, costed at EUR 600 million, will start by the end of 2002, three years later than planned, with completion in 2008. The tunnel will be equipped solely for high-floor platform operation.

Out of the question are hybrid tram-trains, in Karlsruhe-style, given the weakness of demand in the rural areas. The only Karlsruhe-style operation in the region to attract sufficient ridership would be over the existing rail line between Bonn and Euskirchen, 30 km to the west, it was found in a survey conducted in 2000. But these days, Bonn is now cutting its budget, to adapt to the fact that it lost its status as the country's capital.

In the late 1980s came the low-floor revolution, ignited by the Geneva and Grenoble with their low-floor trams of a bold new design. Soon after, the market was flooded by affordable 100% low-floor LRVs. All over Europe, politicians and the public embraced the low-floor tram. The low-floor revolution caught Köln by surprise. The city was half-way through a careful, decades-long process of upgrading, based on a standard floor height of 900 mm. Expensive underground stations had been built to this standards, and could not easily be remodelled to low-floor standards.

At that time, eight Köln tram routes had been converted to high-floor Stadtbahn standards. Starting from the new subway segments, these lines had been upgraded with the construction of high-level platforms over their full lengths. However, four classic tram routes (1, 2, 7, 9) were still largely in their original form, as Stadtbahn norms proved difficult to implement, given the narrowness of many streets through which these lines ran. These four tram routes all bypass the Hauptbahnhof area in central Köln, nor do they use any of the inner-city subways. All four are east-west lines, all using the well-fenced median tram reservation on the long Deutz Bridge to cross the Rhine.

The seeded grass on the Weiden extension's reservation is just a month old, but will soon be a well-integrated part of the west Köln suburban landscape. (C. J. Wansbeek

In 1991, Köln decided that the four tram routes should be deleted from the high-floor Stadtbahn, and that, instead, low-floor trams would be introduced, with an entrance height of 350 mm. Platforms of the four lines were brought to that standard. A low-floor system besides the high-floor Stadtbahn system became a reality; the technical severing-in-two was completed in 1994.

So there are two Stadtbahn systems: the "real" one with 900-mm high platforms, and the four low-floor tramlines. In daily parlance, the locals refer them both to as Stadtbahn or Straßenbahn. Both systems have in common that passengers enjoy stepless entrance from spacious and safe platforms. There is only one short stretch used both by high-platform Stadtbahn cars and by low-floor trams. This oddity can be found in west Köln, in the median strip of Stadtwald Gürtel, between Aachener Straße and Dürener Straße, with a length of about 500 metres, used by low-floor trams of route 2 and high-floor Stadtbahn LRVs of route 13. Here, the double stations contain low-floor platforms for the trams, and high platforms for the Stadtbahn.

Since 1995, a fleet of 120 K4000 class 70% low-floor double-ended LRVs (all in numbered in the 4000-series) has been delivered by Bombardier, and KVB is pleased with their reliable performance. Four additional K4000 class vehicles have been ordered since, to be delivered soon. All four low-floor lines (1, 7, 8, 9) are now entirely operated by these trams. The double-ended K4000 class trams are close copies of a new class of LRV developed by Bombardier for the Wiener Stadtbahn, at Vienna, Austria.

The order made Köln the first West German city to purchase trams abroad, in line with new EU tendering procedures. The K4000 cars underwent final assembly at the Talbot factory at nearby Aachen, a subsidiary of Bombardier. Köln wanted low-cost trams, of an existing type. Political wisdom went hand in hand with good luck. With the K4000, Köln got what it wanted. A grand total of 350 units of similar family design have now ordered by Köln, Saarbrücken, Croydon, Minneapolis, Istanbul, Stockholm, and Den Haag (for Rijne-Gouwe).

The order of the K4000 vehicles meant that KVB stopped being a self-developing pioneer. The new policy is that only vehicles of existing, well-proven types will be purchased. All development costs and risks must be borne by the industry, not by transport undertakings. During earlier years, KVB had teamed up with Siemens, in joint development schemes for new trams. The 1999-launched City-Sprinter promised to become the next stage in this co-operation, and hopes were that Köln's KVB as the launch customer would order some 150 units, after which other cities would follow. Details can be found in this magazine for August 1999, 'Unveiling the City-Sprinter'). That same month, however, the Siemens-built City-Sprinter prototype collided with a fully loaded Stadtbahn vehicle in a Köln tunnel, causing many injuries. The ties with Siemens, which had been the sole supplier of Stadtbahn vehicles, seemed to disappear overnight.

Customer satisfaction with Bombardier, the new supplier, is such that Köln placed a large order for high-floor vehicles (146 units, 55 firm orders plus 91 options, costed at EUR 220), to replace the ageing Stadtbahn-B cars. Afterwards, Bonn ordered 15 identical vehicles, for delivery in 2003. The Bonn cars will be used on routes 16 and 18, both lines connecting Köln with Bonn. The new double-ended cars of a modular design have type designation K5000. Being a direct offspring of the K4000 vehicle, the 28.2-m long K 5000 car has many structural elements and spare parts in common with the K4000. This means significant cost-savings. According to Bombardier, 75% of the parts used are identical between the two designs.

Bombardier-built High-floor LRV K5000
Gauge: 1435mm
Concept: double-ended, modular design, low maintenance costs
Feature: Air conditioning
Length (m): 28.4
Width: 2.65
Height: 3.65
Floor height (mm): 980
Minimum curve radius (m): 23
Voltage: 750v
Weight (kg): 37.800
Passengers: 177 (62 seated)
Motors: 4 x 120 kW
Speed: 80 km/h
Acceleration: 1.2 m/s
Bogies: 3, of which 2 motorised

The K5000 is air-conditioned, the interior of the LRVs is monitored by video cameras, there is automatic optical announcement of next stops, and ticket vending machines are inside. The first car for Köln, numbered 5101, was delivered in February 2002. In the summer of 2002, three coupled sets of were already in daily service on line 3. The K5000 is for service on high-platform lines, but inbuilt foldable steps enable it to also serve lines with 350-mm low platforms.

Politicians started to demand more low-floor lines. Reasons, the positive experiences with the four modern low-floor operated tram routes, the growing preference of nearby Düsseldorf to convert to a system-wide low-floor operation within the next decade, and perhaps also the ongoing quarrelling at Köln between those opposed to more subways and the KVB, as well as criticism from certain neighbourhoods where high-level platforms are regarded as hard to fit into the existing street profiles. In short: they were seen as nuisances in narrow streets. But it cannot be denied that the southern segments of routes 6 and 12 have curves that are too sharp for Stadtbahn-B car operation, so the Düwag 8-axle trams remain there for the time being.

It became obvious very soon that a system-wide mutation to low-floor operation at Köln is simply unaffordable. Yet, this is what many local leaders seem to prefer. In 2000, a majority of the city council declared its preference for low-floor system-wide, which would mean that 150 high platforms would have to be rebuilt to low-floor standards. Amid mounting political unrest, Spiekermann, a consultancy firm, was hired to look into the possibilities. To everyone's surprise, Spiekermann found that three routes (6, 12 and 15) could easily be rebuilt for low-floor tram operation, provided that here and there, stretches would be swapped (between routes 15 and 18 in north Köln) and other alterations applied.

At present, routes 6 and 12 are operated by 8-axle trams; route 15 by Stadtbahn-B cars. The city council lost no time in deciding, in December 2001, that these three lines must be rebuilt to low-floor operation. All three are north-south lines, and will thus come on top of the existing four east-west low-floor tram lines. The lines will cross each other at various points, but there will not be one single meeting place for all seven together.

The Ebertplatz square, north of the city centre, will become the pivotal point, were complicated measures will be necessary to intertwine the three future low-floor tram lines with existing high-floor Stadtbahn lines, among them the above-described route 16. Within a few years, there will be common-level interchange between high-floor Stadtbahn cars and low-floor trams of routes 6, 12 and 15 (by adapting the height of the tracks on which they run). Nowhere else in the world can this solution be seen in practice. But all such adaptations are technically feasible, to the delight of KVB. Even more surprising, the partial re-rerouting needed to adapt the three lines to low-floor operation will even yield savings.

After it had been decided to add three low-floor lines, the 1999 contract had to be re-negotiated with Bombardier in great hurry. But, again, there were no major obstacles. The outcome is that the expected order for the K 5000 cars is reduced from 146 to 55, for delivery in 2003, to which will be added 69 vehicles of a future model, the K4500, for delivery by Bombardier between 2004 and 2006. Moreover, KVB took an option on 18 high-floor vehicles, designated in the 5200 sub-series, which will be future developments (advance electronics, etc.) of the 5100 type within the high-floor K5000 class. The 5200 series cars are planned for delivery by 2010, assuming that KVB places firm orders.

The K4500 is a vehicle, which will be developed on the basis of the K5000 high-floor tram. At present no drawings of the K4500 exist. Conceived as a super-modern low-floor tram, the air-conditioned double-ended K4500 will probably have wheels, mounted on axles, and not independent wheels, as seen in the K4000 and the Combino by Siemens.

By 2010, Köln expects a fleet of some 300 Bombardier cars with many interchangeable spare parts and components. By the time when KVB celebrates its 150th anniversary, in 2027, the Köln system may be low-floor over its full length, but fashions may have changed in between, and the pace of technology is unpredictable. Until now, the strength of the Köln system resides in the fact that the Stadtbahn concept remains flexible and open-ended.

The author would like to thank Herr Joachim Berger of KVB for his kind assistance in the preparation of this article

Recommended Reading
Dieter Höltge and Axel Reuther: Straßen- und Stadtbahnen in Deutschland, Band 7 (Köln, Düren, Aachen), EK Verlag, published 2001, 331 pages, in German, hundreds of photos, incl. Forty in colour. ISBN 3-88255-338-3. Very detailed history, the real standard work on KVB's tram system. Price app. EUR 35

Doris Lindemann, Kölner Mobilität, 125 Jahre Bahnen und Busse, 415 pages, hundreds of photos, many in colour. Published 2002. No ISBN number. Available at KVB's Heumarkt boutique. Broad panorama of the city's transport growth. Price app. EUR 30S

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