A true driver's bus: choice of two cockpits, LED headlamps, practical stowage compartments, perfectly coordinated powertrain and comfort suspension

• The new operators can choose between two cockpits
• The new long-life LED headlamps that are kind on the eyes as standard
• Luggage compartment capacity slightly increased, additional stowage compartments
• Engine and powertrain: perfectly coordinated all-Daimler engineering
• The Setra's gentle comfort suspension

The new Setra S 531 DT is a true driver's bus. Operators can choose between the two user-friendly and comfortable cockpits from the Setra ComfortClass 500 and TopClass 500. The stowage areas – always a special consideration on double-decker buses – are readily accessible. The perfectly coordinated powertrain from a single source is powerful and economical in one. The suspension is not only safe but also particularly comfortable, thanks to full-size 80 percent tyres.

The new operators can choose between two cockpits

The broad scope covered by the new Setra S 531 DT is manifested in its cockpit: it is the first double-decker bus to offer a choice of two cockpits: depending on the intended form of use and the specified equipment, bus operators can choose between the standard-fit from the Setra ComfortClass 500 or the TopClass 500.

A common feature of both cockpits is their driver-friendly basic shape with all instruments and controls clearly arranged and the pendant pedals. With either cockpit, the driver has a multifunction steering wheel and precision-marked and clearly legible circular instruments at their disposal. Positioned centrally in each instance is the informative instrument cluster with its high-resolution colour display.

The control buttons are clearly arranged in blocks of four to avoid any possibility of confusion. The digital tachograph and the electronic key are located in a driver-friendly position to the left of the steering wheel. As previously, the driver operates the transmission by means of a space-saving and self-explanatory pitman arm. Both cockpits feature the Coach Multimedia System (CMS) with a brilliant seven-inch display.

The CMS incorporates the separate entertainment electronics for passenger compartment and driver's cockpit, the navigation and the telephony system in compact and clearly arranged form in a single device. Practical stowage facilities and drinks holders are installed around the instruments.

Cockpit from the ComfortClass 500: functionality and flexibility

In addition to functionality, a high degree of flexibility is another key feature of the cockpit from the ComfortClass 500. The cover over the large open stowage compartment on top of the centre console can be removed, for example, and a fixing pin and cash register can be installed in its place – an important option when the double-decker bus is deployed on regular services. The doors can also be unlocked using the electronic vehicle key.

Cockpit from the TopClass 500: exclusive design

The cockpit from the TopClass 500 represents an even higher standard. It fits even more snugly around the driver and is characterised by an exclusive design: an elegantly curved aluminium bar serves as a surround for the instrument panel, while round air vents add a dynamic touch. The cockpit cover flows harmoniously from the driver's side to the tour guide's side. The driver has diverse information to hand on the display of the Multi Function Key.

As the multifunction steering wheel and instruments, the basic aspects of operation and the control panel as well as the Coach Multimedia System (CMS) all correspond to the TopClass 500, drivers will have no problem switching between buses with different cockpits within the same fleet and will not need any time to adjust to a new work environment. As the space situation as well as the operating logic are identical for all Setra touring coaches, drivers can even switch without any problems between all the vehicles.

The new long-life LED headlamps that are kind on the eyes as standard

The comparatively low seat position in conjunction with the imposing dimensions of a double-decker bus imposes high requirements on visibility. The new outside mirrors provide a better view from the cockpit, as the larger distance from the driver to the mirror enables the wide-angle lenses installed at the top in the mirror housings to be viewed at a more favourable angle.

At night-time the Setra lights up as standard with new integrated LED main headlamps. The light from these headlamps is similar to daylight and is thus less tiring on the eyes than conventional halogen light or xenon headlamps. At the same time, the LED lamps offer a service life roughly equivalent to the vehicle's lifespan. This cuts out the need to change lamps, saving money and downtimes. The new lamps also enhance safety, as a Setra double-decker bus will never be on the road with lamps lit up on one side only.

Luggage compartment capacity slightly increased, additional stowage compartments

As on the predecessor model, the luggage compartment with a practical smooth surface on board the new double-decker bus is accessible via a large rear-end door and side stowage flaps. A space-saving side step in place of the previous step has allowed a slight increase in surface area, as a result of which the luggage compartment now has a volume of 8.4 m³. At the same time, this measure has also created space for a tool compartment and an additional practical stowage compartment in the entrance. There is also a new stowage compartment in front of the front axle, under the driver's cockpit. On top of this, if required there are also the usual stowage options on the right between the axles, beneath the platforms.

Engine and powertrain: perfectly coordinated all-Daimler engineering

Setra renewed the entire powertrain and suspension of the predecessor model back in the autumn of 2013, to tie in with the introduction of the Euro VI emissions standard. The OM 471 six-cylinder in-line engine with a displacement of 12.8 litres replaced the previously employed V8 in the course of this overhaul. This engine continues to deliver an output of 375 kW (510 hp) and an exceptional 2500 Nm of peak torque. The numerous outstanding technical features include common rail direct injection with the unique flexible high-pressure X-Pulse injection system. The engine is extremely fuel-efficient and is a smooth-running, clean and extremely reliable operator. Long maintenance intervals of up to 120 000 km for engine oil changes and 360 000 km for initial cleaning of the particulate filter (every 240 000 km thereafter) lower costs and cut downtimes.

Setra also introduced the fully automatic GO 250-8 PowerShift bus transmission in the course of the overhaul. The features of this perfectly stepped transmission include fast and barely noticeable gear changes and a crawl function for delicate manoeuvring. The engine power is transmitted to the RO 440 bus drive axle, which also underwent extensive optimisation measures. The overhaul has resulted in a further reduction in friction and subsequently more economical and quieter operation – the latter being a key factor particularly on the lower deck of the double-decker bus. A trailing axle with independent wheel suspension enhances ride comfort, improves handling and lowers the vehicle's weight.

The latest engine generation: showing how a good thing can still be improved upon

The latest generation of the OM 471 engine has been demonstrating how a good thing can still be improved upon since the autumn of 2015. With a higher maximum injection pressure, increased compression, a redesigned combustion chamber, a patented exhaust gas recirculation process with flexibly controlled return flow rate, asymmetric injection and a new turbocharger, built in-house, what we have here is a whole bundle of measures that add up to reduce further the already advantageous fuel consumption. At the same time the complexity of the engine design has been reduced by a fixed turbine geometry for the turbocharger, the omission of a wastegate valve and the elimination of the EGR sensor, thereby also increasing its robustness. Duly prepared, the new double-decker bus is all set to begin its working life with a perfectly coordinated and well proven powertrain: OM 471 engine rated at 375 kW (510 hp), fully automated GO 250-8 PowerShift bus transmission, RO 440 bus drive axle.

The unparalleled economic efficiency of the double-decker bus

Predictive Powertrain Control (PPC) and Eco Driver Feedback (EDF) are optionally available to support the driver with individual feedback on their personal driving style. With this combination, long maintenance intervals and its aerodynamically perfected body, the Setra S 531 DT of the TopClass 500 exploits all savings potential to the full for unparalleled economic efficiency.

The vehicle's exceptional maintenance-friendliness is also a factor here. This was an important consideration in designing the new double-decker bus. By way of example, the cooling system on the right side of the bus is now ideally accessible by means of a large maintenance door, as opposed to the previously employed two service flaps. On the opposite side of the bus, another large maintenance door affords access to the exhaust system. A new large maintenance flap on the outside of the vehicle facilitates emptying of the waste receptacle. This flap also offers improved access for any maintenance work on the sanitary installations. 

The Setra's gentle comfort suspension

Drivers and passengers alike will benefit from the suspension which has been adopted unaltered from the vehicle's predecessor. The double-decker bus rolls along particularly gently on its full-size 315/80 R 22.5 tyres. The Setra-designed front axle, the RO 440 bus rear axle and the actively steered trailing axle with independent wheel suspension all contribute to excellent ride comfort. A turning circle of 23.1 m makes the 14 metre long touring coach surprisingly agile, and its large ground clearance ensures the required everyday practicality, for example when negotiating ramps.