Heavy-duty off-road bus transports to hard-to-reach places
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The Praetorian off-road bus was designed by Torsus to transport personnel and equipment over rough terrain and in tough conditions. Praetorian’s gestation from initial sketches to production was less than 12 months. (all images: Torsus)

Off-road bus from Torsus transports to hard-to-reach places

Start-up company Torsus recently launched what it claims is the world’s first purpose-built, heavy-duty off-road bus, the Praetorian, designed to transport personnel and equipment over rough terrain. Suited for regions with tough driving conditions, the vehicle has a range of applications such as mining and the oil and gas industries, military, disaster relief, emergency response, even leisure and overland tourism sectors.

Torsus, whose parent company is Pulsar Expo s.r.o., is an international company with its team spread throughout Europe, and development and engineering of the Praetorian took place in several locations. CEO Vakhtang Dzhukashvili, who is located in Torsus’ Kiev, Ukraine office, was the Praetorian’s brainchild. He came up with the concept and original developments. Further engineering, design and developments took place in the company’s R&D and manufacturing facility in Bratislava, Slovakia.

The entire process, from the initial design sketches to manufacturing of first prototypes and vehicles for sales, took less than 12 months. “Our engineering team has grown since we started Torsus, but the number who were involved in the actual development program was around 18 to 20, including a few external contractors,” Peter Zaiček, Production Director at Torsus, told Truck & Off-Highway Engineering.

Engineering a tough bus

The Praetorian was designed from the ground up to be “the toughest bus in the world.” With its heavy-duty construction, 398-mm (16-in) ground clearance under the axles and standard 4WD, the Praetorian has a payload of up to 35 passengers plus equipment.

Based on a MAN chassis, the off-road bus features a 4200-mm (165-in) wheelbase. It is powered by a 6-cylinder MAN 6.9-L diesel engine that produces 240 bhp (176 kW) and 925 N·m (682 lb·ft). The Praetorian’s top speed is limited to 117 km/h (73 mph), making it suitable for both on- and off-road use.

Several different suppliers and contractors were involved in the vehicle’s development and testing, including MAN. “The key thing was that there was deep cooperation with European certification agencies so that we could achieve full type approval and homologation to ECWVTA [European Community Whole Vehicle Type Approval] standards,” Zaiček said.

He explained that Torsus is also collaborating with suppliers and agencies to ensure the company meets ROPS (rollover protection structure) and FOPS (falling object protective structure) certification, mainly for heavy industry markets, and CE certification. “These areas require additional expertise, so we need to work with selected external suppliers to ensure compliance in these areas,” he said.

Praetorian is manufactured in Slovakia; however, there are plans to expand manufacturing and assembly to the Ukraine, U.S., Middle East and South Africa. “There is a widespread market for this vehicle, with requests and sales inquiries coming from all over the world. By diversifying our manufacturing and assembly in different locations, either through CKD or SKD [completely knocked down or semi knocked down] models, we can speed up supply, reduce shipping and cut import duties that may otherwise make the purchase point impractical for the market,” Zaiček explained.

The Praetorian offers an adaptable and multi-functional off-road vehicle platform with a range of configurations available from transporter to ambulance, fire and rescue vehicles, mobile communications units, cargo and utility models. Multiple configurations and customization options are available, making it adaptable to meet specific customer requirements.

Active safety features or ADAS (advanced driver assistance systems) are included on board “to some degree,” Zaiček said.

The on-board system has a range of driver assistance particularly for the more severe off-road scenarios. “For example, there is decent control, line control, etc. All the on-board safety systems required by the most stringent EU type approval are also included,” he said.

The Praetorian is available to global markets with a choice of left- or right-hand drive. Its engine range is from Euro III to Euro VI, allowing the best options for customers and full vehicle certification for various regions. 

Tackling challenges quickly

The Praetorian team encountered two main engineering challenges creating the first off-road bus.

“First was the joints that connect the chassis to the skeleton, or body, framework,” Zaiček told TOHE. “We had to design a special system that was strong enough to take the shock and twisting and reduce the torsion caused by heavy-duty off-road scenarios. These joints help to reduce movement, shock and shaking in the passenger area and work well to provide better passenger comfort and safety.”

The other main challenge was working within the parameters of achieving full ECWVTA type approval and homologation. “As our vehicle has multiple uses outside of heavy industry (for example, we have RV and camper versions and a ski bus for tourists), it was essential that it could be used on regular roads, and thus required full type approval,” he said. This required the engineers to work out solutions that had the strength and durability needed for severe off-road situations, but that also met full homologation requirements. 

The ECWVTA standards themselves also presented a technical issue because there is no existing classification for an “off-road bus.”  

“This meant we didn’t know whether to try to meet homologation for an off-road truck or for a bus, which have different requirements,” Zaiček shared. The company applied to the EU to implement a new vehicle category for “off-road bus,” which is pending. 

“To develop the Praetorian from concept sketches to production within a year was quite a task. All of our team have a personal commitment to this project and put in long hours and dedication to make this a success within our time frame,” he said. 

To meet their deadline, Torsus’ most senior engineers were personally involved in all aspects of the development, right from an early stage. With the company’s R&D center, manufacturing facility and design office all located within Bratislava, this allowed for good channels of communications and a hands-on approach from each team.  

Torsus CEO Dzhukashvili was directly involved in the engineering and development, often “embedded” within each team. “With a full picture of what was happening and what needed to be done, he was able to make critical decisions quickly,” Zaiček said. 

What’s next? 

Though the diesel buses just entered production in May 2018, Zaiček said the company is looking at alternative powertrains for the future, “which could certainly include electric and hybrid options. One step at a time for us though!”  

Zaiček also told TOHE the company has plans to expand its product line beyond the Praetorian and has other vehicles in the works. There is a smaller 4x4 utility truck currently in development, called the Legion. It will be a multi-use, heavy-duty vehicle with a similar design and profile to the Praetorian, but on a smaller chassis. It could even be adapted for use as a smaller bus.  

“In addition to the Legion, we’re in the feasibility stages for the development of a smaller, special purpose 6x6 vehicle,” Zaiček said. 

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