On the slopes between Riksgränsen, Sweden and Narvik, Norway huge energy savings are possible.

Starting and stopping a train pulling 8,000 tons of iron ore puts a lot of pressure on brake pads, wheels and rails. The potential for environmental and capacity gains are great if one can optimize the train’s movements and drive it in an ‘eco-friendly’ fashion.

Swedish company Transrail has developed the CATO (Computer-Aided Train Operation) system to streamline train movements. CATO improves punctuality, reduces energy consumption, increases line capacity, improves work conditions for the driver, and reduces wear and tear.

The idea of CATO is to exploit time slots when trains wait at signals or pass stations. The system is currently being installed by LKAB on the Malmbanan, in northern Sweden, and by the Arlanda Express, the train service to and from Stockholm’s Arlanda airport.

Computers analyze and control train speed

“Optimal operation of traffic on an entire line with individual trains can not be achieved with conventional signaling systems,” says Per Leander, President of Transrail Sweden AB. “The driver needs to know when the train will arrive at the next station or signal, and how the train should be run in order to arrive at the right time. The timing and speed are affected by many factors and to choose the optimal speed profile requires feeding continuous information to the driver. That is what CATO does.”

CATO consists of a computer and a display that is installed in the train’s pilothouse. It is connected to the Transport Administration’s train control systems and monitors current traffic situations like delays, speeds of each train and locations taking into account meetings with other trains and timetables.

The central computer calculates the train travel times in order to be able to run without stopping or unnecessary braking and arrive on time. The current timetable is transmitted to trains via GSM-R digital radio.

This information is then calculated into a velocity profile displayed onboard that allows trains to meet the traffic management plan, and to drive as energy efficiently as possible.

“We are convinced that computer-aided control of the train will become increasingly common in the future, even though the system may seem complex today,” says Leander. “CATO contributes to optimal train running and reduces driver stress. The goal of our project was not to develop a finished product but that is what it has become.”

The eco-driving of ore trains

Mining company LKAB is particularly interested in CATO. LKAB has purchased a CATO-license and installation in all IORE locomotives is underway.

The ambition is to achieve maximum utilization of the ore line between Riksgränsen and Luleå and to become 20 percent more energy efficient.

Ore train locomotives (IORE) are already equipped with technology for energy recovery: when the train engine brakes, the motors turn into generators. This is particularly valuable on the slopes between Riksgränsen, Sweden and Narvik, Norway.

The energy gains between Malmberget and Luleå are also big. With CATO, ore trains run smoother, energy use is minimized, while the wear on the brakes, wheels and rails is reduced.

The system also increases punctuality thereby improving capacity on the ore line.

High-speed trains with eco-driving

The Arlanda Express bought CATO as part of the company’s environmental and punctuality efforts.

“CATO orders from LKAB and Arlanda Express mean that this new technology is here to stay. We have discussions with other railway companies,” says Leander. “CATO provides the opportunity for substantial improvements in rail service.”

The article was published in January 2012