VOSSLOH Rolling Stock’s four-axle mixed traffic DE 18 entered the market in 2014 and since then more than 145 1.8MW units have been sold to customers across Europe, performing tasks ranging from operating freight services and shunting to supporting construction and logistics, and undertaking rescue operations.

A batch of 10 DE 18s is currently under construction for customers in Italy after the DE 18 secured type approval by the European Union Agency for Railways (ERA) in June 2021. Presentation runs have also taken place in Sweden and Norway and Vossloh Rolling Stock expects certification here, including with ETCS Level 2 Baseline 3, in 2023. It is also eyeing potential sales in eastern Europe.

With railway operators becoming increasingly conscious of their environmental performance as well as the rising cost of diesel fuel, Vossloh Rolling Stock is introducing a range of new features to improve the sustainability of its locomotives, including the DE 18.

Vossloh Rolling Stock has designed its locomotives to be modular, meaning it is possible to install different components and systems depending on the customer’s requirements.

A notable development is the introduction of batteries in the SmartHybrid version of the DE 18, where battery operation can replace diesel engines for last mile applications and in sensitive areas such as tunnels, depots and stations, potentially reducing energy costs by around 10%. The locomotive made its debut at InnoTrans in 2018 and in September 2021 Vossloh Rolling Stock’s won a contract with Nexrail to supply 50 units, with production currently underway at its plant in Kiel. The locomotives will mostly operate in France, Belgium and Luxembourg with delivery due to commence in 2023.

The DE 18 SmartHybrid is equipped with a 1.8MW diesel engine. However, unlike the earlier version of the locomotive, the 1000-litre tank for the 4kW auxiliary diesel engine has been replaced with 144kW NMC lithium-ion batteries positioned below the locomotive underframe. The battery pack can undertake more than 7000 charge cycles, which gives it a service life of around eight to 10 years. It offers around an hour of emission-free operation and fuel savings of 20-50%.

The batteries can be charged using either a 400V 3ac external power source or the diesel engine, taking six hours using an external power supply without electrical preheating or faster if there is heating with the speed dependent on the temperature. Using the diesel engine can charge the battery in 20 minutes while a slow charge using the onboard static converter takes four hours.

Once the battery has reached the end of its service life it can be replaced relatively easily. There is potential to install a more powerful battery back or to revert back to diesel.

Plug-In Hybrid

Using the Plug-In Hybrid option makes it possible to extend the diesel engine’s stop phases by having all the auxiliary systems run off the traction battery. Vossloh Rolling Stock says using the battery for low-power operation requiring less than 400kW is more efficient than using the diesel engine and potentially reduces use by 40-50%, increasing maintenance intervals.

Diesel remains the essential fuel for many locomotives due to the flexibility it provides. Nevertheless, work is underway to reduce its consumption and the impact on the environment.

Fuel consumption varies significantly depending on the duties performed by the locomotive. The greatest savings are made if a diesel-electric traction system is used. However, Vossloh Rolling Stock has developed several additional functions and smart operating modes to further reduce consumption and emissions, which are available as options to customers to enhance the performance of the DE 18.

These include Vossloh Eco Drive, which supports economical driving by providing detailed information on fuel consumption across various parameters: per hour, per kilometre, daily consumption, and total consumption. There is also a limit value sensor and an energy meter recording daily consumption. In addition, a Performance Button Eco can enable the DE 18 to operate at its maximum power output of 1.8MW. Normal operation takes place with a 1.5MW output, helping to save energy.

On the flip side, an Eco Mode Switch can limit the output of the diesel engine to 1.2MW, again providing more efficient engine management. The driver activates this setting using the driver’s console. As well as improving performance and reducing fuel consumption, the engine setting helps to reduce maintenance costs - the reduced output results in longer periods between engine overhauls. This is particularly advantageous during shunting operations, which do not require maximum power output.

Limiting emissions during shunting is also reflected in the addition of the VED engine start-stop function to the DE 18. Studies have shown that diesel shunters can spend up to 80% of their working life idling. Previously limiting restarts was justified on the grounds of reducing wear on the starter and the risk of engine temperature dropping below 60°C and batteries and air tanks becoming depleted. VED enables the engine to restart with no wear incurred at all. The engine shuts down automatically after idling for a set period of time and restarts take place on request or if certain conditions are met. As well as limiting emissions, the function is expected to reduce required maintenance.

Introducing the latest developments in diesel traction can also reduce emissions significantly. A prototype of a DE 18 compliant with EU Stage V emissions requirements will be shown at InnoTrans this month.

The 12V 4000 Stage V engine has been supplied by MTU and the engine can also be certified to operate on HVO biofuels made from hydrogenated vegetable oils in accordance with EN 590 and paraffinic diesel meeting the EN 15940 standard. Biofuels reduce CO2 emissions by up to 55% compared with fossil fuels, and a reduction of up to 95% is expected with the second generation (PTX), which should be available before 2030.

Vossloh Rolling Stock says using HVO presents no significant implications for engine operation or the maintenance schedule. There are also no differences in terms of storage and distribution compared with fossil fuels and no significant cost increases for freight haulers. In addition, the DE 18’s compatibility with European standards means an immediate transition to these types of alternative fuels is possible. Delivery is feasible via truck to existing fuelling sites and it is possible to mix HVO and biofuels with diesel in any ratio.

DM 20

Modularity and sustainability are also at the heart of the DM 20, Vossloh Rolling Stock’s newest locomotive platform and the first to be equipped with a pantograph to collect traction current from the overhead wire.

Designed for freight operation as well as shunting, infrastructure work and rescue operations, the DM 20 has found favour in the market: Paribus Rail Investment Management ordered up to 50 of the locomotives on behalf of Rive Private Investment in 2021 while Vossloh Rolling Stock secured another order for an initial two units with Rail Innovators and Port of Rotterdam Authority. In December 2021 the company secured its largest order yet, a deal with DB Cargo for 50 hybrid units with options for a further 200 locomotives. Delivery of the DM 20s, which will be used for freight operation in Germany, will begin in 2024.

Vossloh Rolling Stock says its primary focus for the DM 20 is offering flexible traction options to its customers. Each locomotive has two different traction sources, diesel and electric. The supplier says there is also the option to update and adapt the traction system as required, even after several years of use.
Three variants have been manufactured so far: the DM 20-EBB, DM 20-EDD and the DM 20-BDD, the latter option selected by DB.

E stands for high voltage and B electric traction. The DM 20-EBB can take traction current at 15/25kV ac and 1.5kV dc. D stands for diesel traction, with the DM 20-EDD equipped with two 480kW diesel engines. The two diesel engines deliver 750kW of continuous power at the wheels and 850kW with time limitation, which Vossloh Rolling Stock says is comparable with existing locomotive types.

A high-voltage system is not fitted on the DM 20-BDD, which is equipped with two diesel engines alongside a 160kWh lithium titanate (LTO) battery for energy storage, which is located beneath the underframe of the locomotive. Here the ac traction system provides 2.5MW at the wheels, which is supplemented by 300kW from the underfloor battery, represented by the letter B.

While not yet in production, a DM 20-EBB locomotive is feasible where the two LTO 350kW batteries provide 500kW to supplement power from the ac traction system at the wheels.

As well as adaptable traction systems, Vossloh Rolling Stock says the DM 20 is ready for future retrofit to other technologies as they emerge, including digital automatic couplers (DAC), cameras for obstacle detection, and augmented reality to support maintenance activities. Work is also underway to introduce condition-based maintenance services for the DM 20.

Sensors and GPS location devices fitted to the locomotive will continuously transmit data to evaluate the condition of essential components using limit values and monitoring logs. In addition, Vossloh Rolling Stock expects to employ augmented reality techniques to assist technicians, improving the accuracy and consistency of maintenance work.

The supplier says this forms part of its efforts to offer a locomotive platform that is flexible and can adapt to future needs. In a competitive marketplace, and with increasingly environmentally conscious clients, these appear essential requisites for future success.