Every vehicle delivered by ZWEIWEG International GmbH & Co. KG is ready for a busy life in two spheres: on the road and on the rails. Bringing this safely to fruition requires German engineering technology, a large portion of solution-oriented thought, an eye for detail, and last but not least, connection technology that functions reliably 100% of the time.
Driving like you're on rails
This was the slogan for a German automotive company shortly after the turn of the millennium. ZWEIWEG has lived this motto in their day-to-day business for the last six decades. The company, which was founded in 1940, currently operates under the name ZWEIWEG International, a member of the ZAGRO Group. At the company headquarters in Leichlingen on the Rhine, around 75 employees are engaged in highly specialized special purpose vehicle manufacturing. 20 to 30 vehicles are delivered per year, which can drive on both roads and also rails. They are used for overhead cable installation, track cleaning, rail welding, shunting, or as rescue vehicles, among other things. Customers around the world esteem these ZWEIWEG conversions. The base is formed by conventional motor vehicles – from pickups to 40-ton trucks.
Every Delivery is Unique
A conversion can take up to twelve months, depending on the tasks that the two-way vehicles are supposed to carry out. “Aside from the rail excavators, we do not deliver any standard products,” explains Dirk Löscher, Design Manager, who has been with ZWEIWEG International for 35 years. “There are countless parameters that we have to consider during project development: track profiles, including curve radii that that we have to cope with and the necessary ground clearance, weight distribution for safe locomotion on rails and roads, retaining the structure gauge, etc. Our vehicles are individualized to an extremely high level.” In addition to the mechanical conversions, like the rail running capability, ZWEIWEG alters and expands the working tools, lifting platforms, superstructures, etc. as well as the entire electrical system of the base vehicle. “This begins with something as basic as the lighting systems: rails and roads have different mandatory requirements for lighting. For rail operation, we completely shut down the street lighting, and vice versa,” explains Löscher.
Manual assembly: The vehicle electrical system is completely modified over the course of the conversion.
Dirk Löscher, ZWEIWEG International GmbH & Co.KG
Each Individual Cable is Modified
The specialists at ZWEIWEG install their own control cabinets in both the driver's cab and also elsewhere in the vehicle. The vehicle application profile determines the control system and the necessary signals. “The controllers process between 100 and 200 signals in each of our conversions. The palette extends from parameters that monitor the pressure on the rail axles, or are responsible for controlling the rail undercarriage, up to to travel clearances or the communications from the working platform to the vehicle control system,” explains Löscher. The electricians on his team are presented with many challenges in each project. The control cabinets and cable paths are always individually designed. The space available in the cabinets is quite limited; the arrangement of a total of 250 to 300 terminal points per vehicle must be precisely prepared. “With an average conversion time of a year, one could possibly conclude that we don't work under time pressures,” mentions Löscher. “However, we are constantly reducing our turnaround times, and the electricians are always the ones who provide the final touches. Finding and correcting wiring errors is time consuming and should be avoided under all circumstances, regardless of the narrow spatial conditions.
Dirk Löscher, ZWEIWEG International GmbH & Co.KG
Reliability and Safety, Down to the Details
Despite all of the individualization, the specialists work with modular concepts; for example, there are standardized terminal allocations for the lifting platforms or the rail undercarriage. ZWEIWEG has relied for decades on the screwless terminal blocks from WAGO for the necessary connection technology. “Safety is incredibly important to us,” explains Löscher. “All cables must always be designed to be absolutely secure. If we were to use screw clamp terminals, we would also have to screw down the unoccupied terminals. We have relied exclusively on screwless terminal blocks from WAGO since the 1990s – a true revelation.” The design manager sees advantages not only in the time savings – crimping ferrules becomes unnecessary when there are no screws – but also in the absolutely secure connections. CAGE CLAMP® connection technology ensures secure connections in the WAGO products. Stripped solid conductors, which are commonly used at ZWEIWEG, can be terminated simply by pushing them in. The vibration-proof connection technology, which is shock tested according to IEC/EN 61373, is essential in rail applications. “Regardless of whether we want to distribute signals or shunt cars, whether we are connecting single conductors to each other or jumping them, WAGO has suitable products for us, that are harmonized to each other, and without onerous and time-consuming screws,” states Löscher happily. He also lists another advantage, “The double-deck, through, and rail-mount terminal blocks from the TOPJOB® S portfolio are designed to be very space saving. Using them is the only way for us to achieve the high density wiring that is required for our vehicles.”
Continuous Improvement
To remain among the top players in two-way vehicle manufacturing, ZWEIWEG relies on up-to-date manufacturing technologies, exceptionally trained employees, and continuous process optimization. Innovations in even the smallest details can have great importance. Therefore, the special purpose vehicle manufacturer welcomed the refinements to the TOPJOB® S rail-mount terminal blocks with open arms: “I/O modules with push-button or lever? For us, this means even faster and safer wiring! The ability to work without tools is a real improvement, particularly in difficult to reach points.” Löscher is already aware of the practical applications. “We welcome any innovations that make our work easier. However, it is more important that WAGO delivers outstanding contact quality paired with true long-term consistency. I cannot think of a single case, in which our vehicles failed because of a malfunctioning clamping unit.” Reliability and freedom from maintenance are also among the competitive advantages for ZWEIWEG.
Author: Lena Kalmer, Communication Manager, WAGO
Control center: Depending on the intended purpose, the commercial vehicle is equipped with numerous additional systems, which process almost all additional signals. Design Manager Dirk Löscher points out that all cables have to be neatly laid out for safe operation.
