Siemens Mobility launches ‘SwissApp’ to reduce ETCS costs

source: Siemens mobility

Siemens Mobility has developed a vehicle equipment solution for the latest generation of ETCS Level 2 functions for Swiss rail transport.

The solution, called SwissApp, is ideal for small series of trains and individual vehicles. A first customer has already been won with the railway maintenance company Scheuchzer AG. The scope of supply includes software and hardware solutions, engineering services as well as commissioning and approval documentation.

With ETCS Level 2, an element of the European Rail Traffic Monitoring System (ERTMS), the train movement is constantly supervised by constant communication via radio-based GSM-R between the train and trackside.

High costs

With the introduction of various ETCS Level 2 routes on the standard gauge network, some Swiss routes can only be travelled on with ETCS equipped vehicles. The intermediate solution with ZUB/Signum and the ETM tag reader is no longer sufficient for these routes.

Upgrading vehicles with ETCS usually involves high one-off costs. In addition to engineering, testing and validation, this applies in particular to the costs of ETCS approval and re-approval of vehicles.

In the case of small series, old or individual vehicles, these one-off costs lead to an economically unattractive vehicle unit price. This poses major challenges for operators of, for example, maintenance vehicles, small series vehicles or historic trains.

The ultimate goal of the ETCS SwissApp solution is therefore to equip railway vehicles with modern ETCS Baseline 3 vehicle equipment (on-board unit or OBU) at the best possible price. To this end, Siemens Mobility is constantly focusing on streamlining and simplifying the integration of OBUs.

A plug-and-play approach

On-board ETCS products usually only have a generic type approval; the corresponding ETCS components have to be configured and adapted for each vehicle, and the on-board integration has to be approved again for each vehicle. SwissApp does not need such a vehicle-specific approval. Simply put, this means: unpack, assemble and go.

Since the configuration options are much smaller with SwissApp, the aim is to obtain a SwissApp-like approval that can be applied to all individual projects.To obtain an operating license, a vehicle project only needs to prove that the conditions for using SwissApp are fully met.

Due to the use of a very restrictive generic braking model, this solution was primarily designed for vehicles operating without too much pressure on schedules. The solution was also designed for the Swiss market, so that the integration of conventional national systems (class B systems) via the STM interface is not foreseen.

Five pillars to facilitate the entire process

A vehicle-specific configuration of the approximately 2000 configuration parameters is dispensed with. A generic configuration is used. Only a handful of configuration parameters (such as the distance between the antenna and the tip of the vehicle) need to be configured specifically for the vehicle. This very rudimentary adaptation should no longer be allowed for each vehicle.

The ETCS is not linked to any vehicle’s control system. Data such as vehicle length, braking percentage, door status or brake status are therefore not transmitted from the train to the ETCS. If, however, feedback is desired (e.g. for brake status), the feedback is done by wire. All communication between the ETCS and the train is done via defined wire interfaces.

For the modelling of the braking curve, very conservative vehicle characteristics were assumed, allowing the same braking model with deceleration curves to be used for all projects with generic approval. The more restrictive monitoring of the braking curve therefore has an impact on driving performance. For this reason, SwissApp is mainly designed and adapted for construction vehicles, shunting vehicles and historic vehicles.


Individual projects are implemented with the help of the SwissApp processing process (consisting of checklists and templates for installation and commissioning) in order to achieve a simplified re-registration of the vehicle. The Scheuchzer AG vehicle is scheduled for approval at the beginning of 2022. With SwissApp, the railway maintenance company can use its fleet for a longer term.

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Author: Frédéric de Kemmeter

Frédéric de Kemmeter is signalling technician and railway policy observer.

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