199304 – Antoniou – Strategies for Train Control Within QR – Part 2: QR’s Direct Traffic Control

QR DTC is a method of rail traffic control via voice radio for non-signalled or Dark Territory operations. It is a cost effective way of controlling trains in Dark Territory when compared with a system such as ATCS level 10, which is too expensive and too complex for controlling large, remote areas as in Queensland Rail’s case. It is also easier to use than Train Order which gets complicated when altering authorities involving crossings with other trains.

QR DTC is based on DTC (Direct Traffic Control) as implemented in 1984 by the Southern Pacific RailRoad in the USA. It has been modified and semi-automated to run on PC’s and also to concur with QR rules and regulations regarding Dark Territory working. It embodies the principles of CTC with wayside signals replaced by Control Points (Block Limit Boards) and avoids the complexity and inflexibility of Train Order which has been traditionally used in areas of Dark Territory.

One of the cornerstones of DTC is in the direct communication (or transmission of authorities) between train controller and driver. No intermediate communications are necessary as is generally the case in train order working. The direct communications is augmented by the fact that DTC authorities are kept simple – there are no explicit crossing, passing, or permissive working authorities. These fundamentals ensure DTC operations are kept fast, reliable, and highly flexible in meeting the needs of traffic staff.

The need for direct Control to Train communications also necessitates the provision of dedicated and reliable radio systems designed for saturation coverage along the length of the DTC territory.

The office equipment consists of an IBM compatible PC with a VGA colour monitor and mouse running under DOS. An 80 column printer is also used as an event logger for hard copy of significant event S. In addition, logging to a disk file is used to continuously record all valid and invalid operator actions.

The on-train equipment consists of a driver’s terminal (an IBM compatible Laptop PC) which is used to decode and display the Authorities, and the train radio. The driver’s terminal is a conventional, off the shelf laptop PC’ which is enclosed in a ‘Cradle’ packed with foam rubber to ensure that most vibrations and shocks are absorbed.

Control to train communications are typically via a dedicated UHF radio system, with on-board VHF radio and Wayside Telephones as backup.

It is important to note that both the DTC hardware and software are non-vital in a Signalling sense and safety is vested in the Train Controller and Driver by virtue of the QR DTC procedures.