Underground revolution

In Hamburg, thyssenkrupp produced its longest and narrowest escalators to date. They are to be used in the subway in Tbilisi.

A bare, steel factory hall in Hamburg’s Billbrook industrial area offers a unique setting filled with gray floors, high ceilings, plenty of steel, and men with hardhats. It’s also the site of a unique accomplishment: The people wearing the helmets have just set a new record for the Group. They have built the longest escalators ever to be manufactured by thyssenkrupp. And the tallest. And the narrowest. Three records all rolled into one – an unprecedented achievement.

Here are the facts. The new escalators bridge a height difference of 45.37 meters – roughly the height of a 15-story high-rise. With an angle of inclination of 30 degrees, the distance from the first to the last of the 494 steps measures 110 meters. By comparison, escalators in shopping malls usually bridge a height difference of four to six meters, and their length is generally between 10 and 15 meters. The installations are also narrower than previous models, without requiring passengers to forgo room and comfort.

Where do they use slender steel giants like these? The answer is far from Germany, in a place where the soil is marshy and engineers have to dig deep into the earth to find a stable foundation. Such are the conditions underground in large parts of Russia and in countries along its borders. In this case, the destination was a subway station currently being built in an area to the west of central Tbilisi, the capital of Georgia.

Some history: In September 2014, Project Manager Ronny Ischganeit and his team initiate the first phase. The ­requirements of the customer are as strict as they are challenging, but it isn’t the enormous dimensions of the installations that present the biggest challenge. The customer wants three escalators to be installed in a train station duct that has already been built. Standard escalators are too wide, so they will need to be slimmed down.

The public transportation company in Tbilisi made the specifications in response to the growing number of passengers riding on the city’s two subway lines, a development that can be observed in several large cities in Eastern Europe. In Moscow, for example, subway trains run every 90 seconds, but in some cases they no longer stop at the stations, because no more passengers can be transported from the platforms via escalators.

Saved by the drive

But how can you make escalators narrower? The steps, at least, have to remain at the legally stipulated width; there’s no room to maneuver there. Ischganeit and his team solved the riddle right at the outset. The drive (the motor and gears) would not be installed in the supports for the stairs as is usually done, but somewhat deeper, centered in front of the installation, thereby reducing the width by 250 millimeters. “Our solution enables us to increase the capacity of the escalators in the shafts by 50 percent,” says Sales Manager Flemming Bergmann. There are also plans to install eight similar models this year in the subway in Baku, Azerbaijan, which is an impressive achievement by the Hamburg team. Development and construction took only two years – quite a feat.

In September 2016, the individual sections of the three escalators finally stand fully packed at the factory workshop in Hamburg. A model is still assembled. At the push of a button, two 66-kilowatt motors whir to life with enough power to transport 336 people. Each of the two drive chains has a tensile load of 85 metric tons, enough to pull 113 Volkswagen Golfs. And the escalators move faster than in the EU or America. In Russia and other CIS countries, a speed of 0.75 meters per second is normal, while in the United States and Western Europe the standard rate is 0.5 to 0.65 meters per second.

"Our solutions enable us to increase the capacity of escalators by 50 percent.”


Almost two and a half minutes per ride

Regardless of the speed, the length of the escalators means that passengers in Tbilisi will ride longer than someone going to a train platform on a standard escalator, for instance. This is because it takes almost two and a half minutes to reach the train platform. When you look from above, you can’t even see the end of the escalator in the subway station because it runs so deep underground.

Under the leadership of Mike Schmidt, 14 fitters worked down there until well into January, assembling the various parts of the three escalators. And the working conditions were unique. Heavy segments weighing up to 14 metric tons were hoisted into the duct through a shaft before being assembled.

The transit authority has yet to determine when the new station in western Tbilisi will be commissioned. But one thing is clear: When that happens, passengers will ride underground on the most modern escalators in Georgia.