Richard Lambley meets one of Brazil’s TETRA users: Supervia, a regional commuter railway operator now preparing for a vast increase in passenger numbers

Almost as potent an icon of Rio de Janeiro as the Sugar Loaf Mountain or the giant statue of Christ the Redeemer is the clock tower of the Central Station. From this point, some 260 kilometres of commuter lines operated by Supervia extend into the outlying districts, carrying half a million passengers every day.

As the crowds build up in Central Station at the start of the evening rush-hour, you can gain an impression of what this passenger load feels like. But it’s soon going to be far heavier: according to Supervia’s forecasts, the numbers will grow to one million by 2015.

To cope with this demand, the company has ordered dozens of new trains to add to its fleet. At the same time, it is working to increase the capacity of the existing tracks by introducing new signalling methods – the Automatic Train Protection (ATP) technology used by many of the world’s most advanced railways.

As part of the project, Supervia has replaced its mobile radio network – a now-obsolete analogue system from Telefunken – with a IP-based TETRA system by Teltronic. Seven base stations were needed to cover the mountainous terrain, plus a gateway repeater to serve an outlying shadow area.

Together, these supply solidly reliable voice coverage to the ends of the lines. But they also provide the essential data transport required for implementing ATP.

Doubling capacity

With ATP, Supervia will be able to reduce the headway, or spacing, between trains, enabling more of them to use the same tracks. “Nowadays on the central line we practise an interval of about five minutes between the trains”, explains João Gouveia, director of operations. “But when the ATP is reached, it will be about three minutes or 2½ minutes. So we double the capacity. Nowadays we have about 10 trains per hour, but with the ATP it will be about 20 trains per hour.”

Teltronic is currently working with the supplier of the ATP equipment, the Canadian company Bombardier, to integrate the two systems.

With ATP, the trains will detect balises – radio beacons laid along the track – and will report the information over TETRA data channels to the operations centre (CCO) in Rio for processing. The system will also relay diagnostic information from the train and will handle any abnormal situations. “If you have any non-compliant condition, by exception, it will be reported to CCO”, continues Mr Gouveia. “If the balise is defective, the computer inside the train will read the defect to the CCO through TETRA. Our intention would be TETRA communication with ATP all the time.”

Dispatching by TETRA

“Today they use only voice, but they are going to upgrade in order to use the system to make the signalling”, adds Paulo Ferrão, Teltronic’s commercial director for Brazil. “All the signalling system is going to be transmitted by TETRA. Together with this upgrade, they are going to do an upgrade in the dispatch centre, and all the dispatching is going to be by TETRA.

“With the new system, dispatcher will be able to see the diagram of the line on the PC screen, with the positions of the trains. He could put the mouse over the train, click and talk to that train.”

This is all in addition to the basic uses of the TETRA system for voice communications between individuals and groups. For example, work groups in Supervia’s train depots can keep in touch with one another, and train drivers or maintenance workers can communicate with the operator in the CCO. All are covered by the system.

Through another enhancement of the TETRA network, the CCO operator will be able to make announcements direct to passengers on station platforms, or even aboard trains, over the on-board public address system. “Nowadays we don’t have communication inside trains [except for] the operator”, Mr Gouveia says. “But if the trains stop between stations, it’s a big problem.”