A polished look for border traffic
Homogeneous coating systems: FreiLacke coats DB locomotives with ultra-high solids and powder coatings
In cooperation with a number of coating manufacturers, Deutsche Bahn AG has commenced a long-term project that will run until 2022. At the DB Wittenberge/Elbe workshop, articulated railcars are coated with various coating systems and inspected annually. To date, Döggingen-based FreiLacke has coated one locomotive with coating systems.
The signal-red regional trains of DB Regio AG operate up and down the Berlin-Stettin line up to eight times a day. Located just 120 kilometres from the German capital, the Polish city offers many places of interest. The section of line is operated by DB Regio AG and the trains are articulated railcars (so-called GTWs) manufactured by Stadler Rail. Due to their sustained operation, the trains undergo complete interior and exterior refurbishment at least every six years. "One of the main issues is graffiti, which is an ever-increasing problem," said Dr Christian Bohne, head of material and joining technology at DB Systemtechnik GmbH in Kirchmöser.
Two coating systems, one look
In spring 2016, FreiLacke received the order to coat a regional train to both improve the quality of the coating and minimise the recoating time. "For DB Regio AG, it was important for the coating system to demonstrate a high level of UV resistance and also be able to withstand aggressive graffiti cleaning agents," explained Georg Biber, vehicle construction sector sales manager at FreiLacke.
The first step at Wittenberge was to coat the pre-primed surfaces on the lower part of the train, the windows and the roof with a basalt grey ultra-high solids coating (UHS). This UHS coating is a solvent-based, ultra-high solids base coat with a solids content of 80%. Due to its excellent coating and application qualities, this coating is the ideal product for industrial goods and construction vehicles. The material produces a high-gloss finish and can be air-dried or dried in the oven at up to 80°C after 40 min. RT (20°C).
Step 2 involved painting the light grey horizontal stripes and door sections. Only then was the GTW ready to be coated in its primary and distinctive traffic-red colour and the easy-to-clean 'VFP60928-4-01' clear coating. This protective coating for colour and metallic paints is suitable for internal and external use and has a high level of weatherability and mechanical resistance. The coating is dust-dry after only 20 minutes.
Eight ventilation grids on the GTW were simultaneously coated with cathodic EC 'Freiotherm Automotive WK 4035HRU999' and FREIOTHERM facade powder coating PF1003ARG320 by external providers. The latter has GSB and Qualicoat material approvals and has been tested for the external technical area in compliance with DBS 918 340. A final step saw the application of Freiotherm HighSolid clear coating 'KO1853LRA999', which is resistant to graffiti removers such as 'AGS 221' for at least 16 hours. The coating is also highly UV-resistant (Florida testing:
24 months, residual shine 91% at 60° angle).
Greater flexibility for installed parts
"It was important for us to show that various coating systems applied to a train could meet the requirements and create a homogeneous surface – that goes for manually applied coating with liquid paints as well as industrially coated cathodic EC powder coatings or baking coatings applied by suppliers and contract coaters," said Benjamin Weiss of FreiLacke sector sales. "This means that installed parts such as windows, external door unlocking mechanisms, ventilation grids, doors, faceplates and many other external parts can be coated prior to installation without there being any deviation in colour or shine." The resulting benefits to companies are faster throughput times and a reduction of VOC emissions in their workshops.
The coating manufacturer from Döggingen in the Black Forest has long-since been a respected supplier in many industrial sectors with its coating systems. Horizontal coating systems are powder, industrial, electrodeposition and Durelastic (surface solutions for composites) coatings for a variety of different components that are installed flanking each other (hence horizontal). "The components harmonise so well in terms of colour, shine and texture that they can be installed next to each other on a railcar, construction vehicle or similar without any problem," said Weiss.
The total success of the coating system concept from the Black Forest specialists is impressively demonstrated in the DB Wittenberge workshop, where the ventilation grids fit perfectly into the red railcar without any optical differences whatsoever. All the components come together as one homogeneous whole.
The GTW has now been back on the tracks since 16 January 2017. Until the next inspection in six years time, the GTW will be operating in local border traffic between Poland and Germany. Thanks to its pristine surface quality, the train will no doubt be setting a shining example to commuters and tourists alike.