Zero degrees and light snowfall, February in Rovaniemi, Finland – when our plane landed in the early evening, only the almost waist-high layer of snow hesitantly shows us how extreme the conditions here normally are. And whyMercedes-Benz choose to put their buses through their paces right here in Lapland, not far from the Arctic Circle. For about three weeks in the year, the test engineers headed by Andreas Dingler, Head of Testing for Daimler Buses, come here every year to test prototypes, new developments and also current systems to their limits and to check their performance and reliability. The Arctic climate in the Finnish part of Lapland is of course not enough on its own - for the various test drives, the engineers and technicians who have come here drive the vehicles mainly on the test circuit created especially for commercial vehicles near to Rovaniemi.
11.5 hectares in size, or about 16 football pitches, this stretch of land has ideal test conditions for buses: a circuit 280 metres in diameter and a run-up trail 1.3 kilometres long, gradients of three, five and seven percent, a handling course which even a Citaro G can drive on, and on top of all that, 100 metres of heated asphalt to test the braking performance for different friction values. "You can of course simulate winter tests, but not in every detail and not in the depth that is possible under real conditions," said Andreas Dingler commenting on the necessity for such elaborate tests, adding: "As a premium manufacturer, we owe it to our customers!" And hardly any mention is made of the fact that the buses have already run a real marathon before starting the first metres on the test circuit.
Mannheim to Rovaniemi. The vehicles have already driven more than 2700 kilometres on their own wheels before the real testing begins.
And the journey there and back can be a real adventure too. "You can end up at half past eleven at night lying under a bus at a service station holding a spanner," said Andreas Rölle from Engine and Powertrain Development, with a smile. Because one thing is clear: the winter testing is not only a real test of strength for the buses; the test teams also have a really tough job to do. "At minus 38 degrees, a spanner feels damned cold," said Andreas Rölle convincingly, mentioning by the way that his third child was born just a week before he set off for Finland. For the dedicated engineer, it is part of the job "that you go off twice a year for a few weeks when new developments have been made."
Even if it seems a little bizarre at first glance: the last one to drive on to or to leave the test area always has to wait until the gate is properly closed – so that no reindeer can stray on to the grounds and cause an accident. However, if you consider a giant such as the Citaro G driving around the circuit at over 50 km/h, testing the efficiency of the anti-jackknife control in simulated double lane changes on ice and snow, then these safety measures seem quite sensible. And the coned-off track is narrow enough without reindeer – and yet the 18-metre bus masters it with confident supremacy. The rear follows the front section at all times with almost stoical calm.
Even on the narrow, snow-covered roads of the little town of Rovaniemi with its population of 60,000, the Citaro G is absolutely calm and confident, winding its way through the rush-hour traffic and over the narrow bridge crossing the Kemijoki river.
But for the time being, back to the tests of the current Travego. Like all Euro VI vehicles, the Travego is tested here in Finland in advance, undergoing a further series of tests to find out if the Mercedes-Benz cold-start ability, transmission and exhaust gas aftertreatment system still function perfectly in accordance with requirements. All of the current models are constantly tested to maintain the high standard which customers have come to expect from a Mercedes-Benz bus. "When you see how easily a diesel engine starts at minus 35 degrees, needing less than five seconds – it's a fantastic sight," said Andreas Dingler proudly.
And this pride is absolutely justified, because whatMercedes-Benz Buses achieve in test performance can truly be classed as unique – the extensive test catalogue, the test logs as well as the intensity and extent of the tests are incomparable.
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