Tugger trains

The roots of the success story of STILL’s tractors and tugger trains can be traced back to Germany’s economic miracle in the 1950s and the boom in logistics that went along with it. As early as 1946, STILL started out on its path to success with the EK 2000 electric cart. The robust e-truck marked the start of STILL’s switch to becoming a producer of industrial trucks. The logical continuation of this development came in 1948 in the form of the manoeuvrable ‘Muli-Mobil’ three-wheel tractor. This compact electrical truck with a tight turning circle captured the mood of the time and the versatile machine became an indispensable piece of equipment in the port of Hamburg. The three-wheel tractor bearing the company logo on the front could tow up to ten trailers between the countless storage sheds.

Streamlined traction -

"just in time" ...

The speed of industrial processes has developed over time. Classic Henry Ford-style assembly line production, as was the norm in the past, aims to assemble as many identical end products as possible in the shortest time possible. However, this system cannot keep pace with increasing diversification and customisation. Shortly after the Second World War, Japanese production manager Taiichi Ohno and his colleague Shigeo Shingo therefore developed the Toyota Production System, based on the ‘just in time’ and ‘Kanban’ concepts.

The fundamental idea was to differentiate between activities that add value and those that do not, in order to consistently prevent any waste. In the automotive industry today, around a third of all parts are delivered ‘just in time’. Manufacturers of computers and consumer electronics have also been quick to adapt this lean process for their industries. The principle is this: as soon as a customer places an order, the variants they have ordered are recorded and the following details analysed: what parts are required where and when, how many parts need to be which colour, how many are made from which material, and what connecting parts are required for assembly. This results in a significant reduction in throughput times and considerable reductions in warehouse stock and therefore costs.

…and also "just in sequence" –

but always with the right trailer

The next stage is called ‘just in sequence’. This involves additional pre-sorting of parts in line with the assembly sequence, so that employees have everything they need at hand. But how do the parts get to the production location just in time or just in sequence? This is where the idea of a tugger train comes in. Since the turn of the millennium, this term has been used by German and European experts when talking about synchronised internal materials supply. The tugger train is less a technical innovation than a sophisticated concept – after all tractors with trailers have been used in logistics for many years, the STILL Muli being just one example. However, with customised schedules and appropriate transport systems, tractors and trailers can completely replace the need to use forklift trucks in a production process.

Efficiency and flexibility

The effects of streamlining

Production without forklift trucks reduces the number of trucks and transports in the material flow. The transit time per load carrier is reduced to a minimum and work processes become faster, more efficient and safer. Moreover, the investment resources and operating resources saved can instead be put to use in other areas.

Intelligent circular economy

The milk run principle

Picture the streets of British towns in the 1960s: the milkman makes his fixed round and knows that he needs to replace the empty bottles outside every front door with full ones. It is a perfect example of a permanent supply cycle. Supply using tugger trains follows this successful model. However, the tugger train is a concept and not a vehicle in the conventional sense. It involves using tractors and trailers in such a way that production can be carried out entirely without the use of forklift trucks, setting new standards in efficiency and safety in the process. In the parts warehouse, the train driver shunts the trolleys loaded with carriers into the frame attached to the tractor. They then travel a pre-defined route along the assembly lines, deliver the necessary parts just in time or just-in-sequence and pick up empty containers or trolleys with semi-finished parts that have already been assembled.

Always on the path to success

STILL LiftRunner®

In 2008, STILL and BMW joined forces to develop the STILL LiftRunner® as a key tool to enable production supply without the use of forklift trucks according to innovative lean principles. The process logistics system, which is based on the milk run principle, has since been successfully implemented by BMW in its production supply. The STILL LiftRunner® has also established itself right across the market and continues to set standards in the industry with ongoing refinements and enhancements. The STILL LiftRunner® is ideal for automating your intralogistics processes. The flow of goods can be entirely automated right through to the production line, with different lines being supplied efficiently and exactly on time.

On track to achieve your goal

The perfect combination of trolleys and frames

Parts are transported on trolleys loaded with carriers, which are rolled onto the frames that are towed by the tractors. The lifting power required comes from the tractor. Advanced frames lift the trolleys before transport begins, which minimises noise when driving and reduces wear to the rollers. The design of the frames has been consistently refined in recent years, with STILL launching the B-Frame in 2015. The main advantage of this frame is that it can be loaded and unloaded from both sides, which makes route planning and transport more flexible.

Digital trains are gaining momentum

Automated tugger trains

The digital revolution and demand for increasingly dynamic production and supply chains across all sectors are two sides of the same coin. The online economy with its high demand for transport logistics, shorter product lifecycles, rising wage costs and skills shortage are all forces shaping this development. Higher customer expectations with regard to customisation, delivery time and lower batch sizes are also reinforcing this trend. As a result, irrespective of the specific industry, automated solutions in the form of driverless transport systems offer a promising approach to improve companies’ competitiveness.

Acclaimed by industry experts

Gaining traction with the IFOY Award

From supplying the production area through to distribution logistics: automated tugger train solutions will be an essential part of internal load handling in future. Tugger trains with driverless transport systems are already being used successfully by many industry leaders, and it is paying off. For good reason STILL was awarded in 2019 the prestigious IFOY Award – the industry’s answer to the Oscars – for its automated electric tractor LTX 50 plus LiftRoller iGo systems with automated loading and unloading function, in the ‘AGV & Intralogistics Robot’ category. This is the first fully automated solution to transport and handle loads of up to 1200 kg per trailer.

As fast as the fire brigade

STILL LiftRunner® at production pace

As a leading provider of fire safety equipment, Ziegler GmbH particularly appreciates the speed and flexibility of tugger train solutions. These systems offer flexible synchronised production supply with low material stocks, which reduces internal traffic as well as the risk of accidents and ensures that employees are deployed according to the specific task requirements, something that is vital in view of the skills shortage.

The specific task at Ziegler was to develop and implement a uniform concept for the company’s production logistics. STILL’s tailored solution: after analysing the company’s intralogistics and advising them accordingly, an 11-metre tugger train with C-Frame trailers was put into operation. The LTX 70 electric tractor serves as towing truck. STILL tugger trains are now used to supply the buffer locations along the assembly line. Ziegler’s project manager Mirco Adam explains: “When planning a tugger train system like this, you have to bear in mind that it also needs to be integrated into the company’s existing infrastructure. Our analysis dictated that a maximum tugger train length of 11 metres was required. The train also needed to be highly manoeuvrable due to the angular layout of the building. In addition, it is only possible to travel the routes in one direction as there is nowhere to turn around. For this reason, the train has to go outside to return to the transfer point.” So, just like the fire brigade in many ways.

More than just meals on wheels

24/7 health service via tugger train

More than 60 clinics and scientific institutes, approximately 1500 beds, and around 341,000 patients cared for each year at the University Medical Center Mainz – in short a whole organism with STILL tugger trains providing the heartbeat, 24 hours a day. According to the proven milk run principle, STILL R 07 electric tractors with LiftRunner® C-Frame trailers are used to transport meals, laundry, empty containers and recyclable materials around the hospital grounds. In addition, there are special load carriers for mail, oxygen, bottled gas and cable reels. As Bernd Broszehl, Head of Central Services at the University Medical Center Mainz, explains: “From 06:00 to 22:00, our tugger trains are constantly on the move. Up to 4500 meals are delivered from the kitchen to the wards for 1500 inpatients in the morning, at lunchtime and in the evening.” Safety is a key concern here, explains Andreas Bade, Regional Head of Sales at STILL’s Frankfurt subsidiary: “When you climb into the R07 tractor and press the hydraulic lever, all of the frames are automatically lifted. When you exit, they are automatically lowered again. This means the carefully deburred stainless steel trays can be lowered to floor level using our patented LiftRunner technology and the trolleys can be loaded and unloaded with very little effort. The meal trucks’ electronics are protected when driving and the trolleys’ rollers are preserved instead of being damaged. ”Man and machine work together in harmony here in the name of healthcare.

Man or machine?

Both! And ergonomic to boot!

Qualified and healthy specialist employees are a company’s most important resource. The main focus of automation is not to reduce staff, but rather to use existing resources more efficiently by adding value and protecting employees’ health. Automation using tugger train concepts relieves employees from the burden of performing physically demanding or repetitive tasks and creates new roles that require creativity and expertise. This benefits the people in the company as automation opens up new fields of activity and responsibility. One example is logistics being deployed for an entire production line instead of just one individual process step. Also, the ergonomics are improved: the tugger trains are more ergonomic in their handling as the operator spends less time sitting down. Additional accessories like the TrolleyMover 4W 15 for loading and unloading B- and E-Frames or the trolley titling function by STILL also ensure improved ergonomics when working thanks to their optimal working height and easier access to containers. Or to put it another way: on track towards a healthier work environment!