Wolfgang Leindecker, vice president for machine networks and public transport at Kapsch CarrierCom, explains how real-time monitoring of light rail vehicles in the Austrian city of Linz is offering new insights into vehicle performance.
AS any rolling stock engineer will know, making small adjustments to vehicle components or subsystems can yield substantial operational and financial benefits when applied across a whole fleet. But getting to know how those systems are performing and how much energy they are consuming is often a difficult task.
Historically trial and error played a big part in the incremental improvement of fleet performance, and the only way to really establish the effectiveness of a particular measure was to try it out in service over a period of weeks or months. But with the aid of modern telemetry, our understanding of how these systems perform in service - and how they can be optimised - has been totally transformed.
In the Austrian city of Linz, local public transport operator Linz Linien was keen to discover how it could improve the energy efficiency of its tram fleet. Until recently the only way it could do this was by looking at its annual energy bills, but this only provided very limited retrospective information on how and where energy was being consumed.
Linz Linien therefore decided to use a machine-to-machine (M2M) telemetry solution from Kapsch CarrierCom, Austria, to collect and interpret data on vehicle performance. The system generates data from live operation, and around 50 system parameters are measured on the LRV, via an Onboard Unit (OBU) which is fitted to the vehicle. The OBU collects the data and transmits it in real time to the operations centre, where the information is evaluated continuously.
The Kapsch Asset Management Platform (APU) converts the raw data collected during operation into information relevant for the operations manager. This includes information about the condition of the vehicle, acceleration, route, braking, sanding events, status of auxiliary systems, and consumption rates for auxiliary power. It also displays information on any energy-saving measures implemented on the vehicle.
The telemetry data is recorded at specified intervals or on an event-driven basis, depending on the measurement parameter. For example, it may be necessary to record the throttle position every 128ms, but other parameters, such as a pantograph fault, may only be transmitted when they occur. Data collection is configured and managed using a software application on the OBU. The software does not actively access the computerised operating system of Linz Linien, but passively transfers parameters which are already measured. This means there is no way that the operation can be negatively impacted.
The system gives the operator access to both real-time and archive data in the form of detailed reports and analysis, allowing long-term evaluations to be carried out on the performance of subsystems. Saved data is made available to individual user groups through a portal interface, enabling detailed analysis to be carried out.
Using this detailed real-time information, Linz Linien can make decisions about potential adjustments during live operation. These analysis options effectively put the operations manager in the driver's seat as he can immediately assess all the relevant information about the vehicles and their status and position.
Previously, the entire energy consumption of a tram was a matter of pure speculation and calculation, whereas now the actual energy consumption for driving, heating, air-conditioning and similar activities is clearly evident. An additional measure is used to increase the mileage of wheel and rail. It is possible to reduce the sand quantity expelled - during acceleration and deceleration of the vehicle - and thus reduce wear in the case of both wheel and rail.
The results of the initial pilot project with tram equipment from Linz Linien points to an energy saving of 10.2%, which was achieved just from adjustments to operation of heating systems, between October 2013 and January 2014. This corresponds to the annual energy consumption of around 300 households or the equivalent of 85 tonnes of CO2 per year, and further savings are anticipated. The results of the trial surprised Linz Linien, which expected to achieve energy savings of around 5%.
Another surprise was a substantial fall in sanding events. The trial led to a 53% reduction in sanding during acceleration, and a 32% cut in sanding during braking, with obvious implications for track and wheel wear. This led to an adjustment in the rate of sand application. Initially drivers were unhappy with the new rate of sand application, but following further fine-tuning, a rate was set which reduced the impact on rails and wheels without adversely affecting vehicle acceleration.
The system was also used to address a problem with noise and vibration in the city's tram tunnel, which had led to complaints from a nearby theatre. Kapsch set up a speed monitor on the system for this location which resulted in a reduction in the maximum speed.
Such measures really depend on the support of drivers if they are to achieve their aims, and Linz Linien has engaged with tram drivers right from the early stages of the telemetry project. The operator is considering a driver of the month scheme, which makes eco-driving a competitive activity.
Each tram fitted with the Kapsch OBU transmits around 600MB of telemetry data to the data centre per month. The data packets, which are provided with a timestamp, are transmitted at five-second intervals over a 2.5/3G data connection. Each device is authenticated with a 128-bit subscriber authentication key during registration in the operator network via the integrated SIM module.
Data can be transferred from the mobile operator to the Kapsch data centre over an encrypted VPN connection, although this was not used in Linz. The telemetry board computer must register on the Kapsch software platform based on predefined parameters over this secure data connection, which ensures the authenticity of the information transmitted. The data is processed by Kapsch's earthDATAsafe secure data centre. This data centre operates in accordance with the ISO 27001 information security management system in order to comply with German and Austrian data protection laws.
Special rail-certified industrial computers are used for the OBU, which meet all relevant standards. The Kapsch software installed on the Linux and OSGi-based onboard computers processes all measurement data generated by the sensors (MVB, IP, RS232, RS485, CAN and Ibis Bus), and can also store data locally for up to two days.
Measurement
The 50 measurement parameters covered by the OBU can be grouped into three categories.
The first category relates to energy measurement. The onboard measuring unit was specially developed by Kapsch with the support of the vehicle manufacturer Bombardier and consists of an energy meter together with current and voltage transformers. These sensors measure overall energy consumption and record all the energy values relevant for traction, in the case of acceleration and regenerative braking performance, as well energy lost through braking. In addition, the sensors also measure the energy consumption of auxiliary systems such as heating, ventilation, and air-conditioning (HVAC) as well as door control and lighting, thus enabling relevant energy-saving measures to be drawn up.
The Multifunction Vehicle Bus (MVB) used on the LRVs provides the second category of measurement data. With the support of Bombardier, secure unidirectional access to defined protocol information was created via an IP-based interface. The MVB provides real-time data for the control interface of central control units, such as throttle position, speed, temperature, sanding events, air-conditioning systems, diagnostic and error messages, and other driving process data. Control and status signals within the vehicle are also transmitted in this way.
An additional serial interface transmits the data from the bus of the Integrated On-Board Information System (Ibis) to the OBU. Ibis coordinates the functions of the computerised operation control system in the vehicle and controls passenger information systems, among other things. Passenger count data generated by stereoscopic cameras at the entrances to the vehicle are transmitted via this interface.
The third category includes data generated by additional sensors installed by Kapsch. These may include GPS location information for exact route positioning as well as direction of travel. The implementation of special sensors for the generation of measurement data relating to vibrations on trams, wheel flats, and the formation of grooves on rails is also planned.
The data provided by the onboard sensors in relation to position and occupancy rate can contribute to an improvement in service quality for passengers. This information could be made available to passengers via a smartphone app in the future.
Asset management platform
At the core of the solution is the Kapsch Asset Management Platform (AMP) developed and operated by Kapsch CarrierCom. This software-as-a-service platform is designed for a wide range of M2M applications. This is the basis for the Kapsch Vehicle Efficiency Reporting & Analytics solution (Vera) used by Linz Linien.
All information is via web-based portals and the solution can be integrated into existing IT infrastructure, which means various user requirements can be met without an in-depth knowledge of software development. Portal components (portlets) are integrated into existing applications and websites and the portal is adapted through configuration; which means no programming knowledge is required. The flexibility of the portal means the information display can be adapted for different user groups, including management, passengers, maintenance staff, and dispatchers.
One of the primary aims of the project has been to encourage more energy-effficient driving.
So far Linz Linien has equipped three of its 55 trams with the system, but plans to roll it out over the remainder of the fleet in the near future. It is also looking into equipping its bus fleet with the same technology.
A key advantage of using telemetry in this way is that the benefits continue to accrue over time as operators learn more from the data at their disposal and begin to identify trends in the performance of their vehicles. As the months go by, Linz Linien continues to optimise the system to make public transport in the city even more efficient.
