During the recent Bentley Forum, Bertie Opperman, Engineering Technician at Spoornet Johannesburg, received the award for most innovative visualisation design for his design of a clamp lock for the railway signalling department. Bertie's prize was a trip to the Bentley user conference in Philadelphia USA.

C1h clamp lock

Trains are diverted from one rail to another by turnouts or points. The steering of wheels from one track to the other is accomplished by two moveable blades. The blades need to be positively locked in position to prevent derailments. The position of the blades and the locking thereof are detected and relayed to the interlocking, which is responsible for the safe movement of trains. A rail-mounted points lock or clamp lock may be used to provide the above positive locking and detection.

Spoornet recently ordered a prototype 1:20 turnout from VAE Austria for intstallation on their coal export line. The locally produced C1h clamp lock had to be adapted to fit the new design for the blade drive and a new system designed to drive, lock and detect the moveable 'V' at the crossing.

By using Bentley Modeller, the clamp lock was adapted and designed to operate, detect and lock the points blades and moveable 'V' on these new turnouts. Each part had to be designed separately - a process which took at least four months. A 3D model was created and animated to establish exact problems on the movement of the different parts.

The stroke differed for each of the drive positions and the locking of the moveable 'V' by clamp lock has never before been attempted in South Africa. A full working model on CAD was the only way in which the clamp lock could be designed accurately and the various strokes calculated correctly. The signalling equipment had to be ready for fitment as soon as the imported points set was assembled. The project was implemented with great success. The model of the clamp lock will also be used for training in the future.

Standardising on Bentley

Spoornet's drawing offices across the country standardised on Bentley software two years ago. Although the change has been slow, they are beginning to reap the benefits of standardisation.

The main programmes used are 3D Modeller, GeoGraphics and Repro-Graphics. ReproGraphics is especially useful for scanning existing paper drawings and editing it in Tiff format. The type of drawings generated are mainly maps of railway links, rail network diagrams, mechanical manufacturing diagrams, circuit and wiring diagrams as well as single line display and structural diagrams. They have a total of 40 Microstation J licences. Interlinking companies such as Metrorail and Protekon have also converted their drawing functions to Bentley.

Bentley Africa

(011) 482 3262

bentley.sa@bentley.nl

www.bentley.com

Installed clamp lock. This is the clamp lock as installed at the end of the turnout

Moveable V

Moveable V assembly. The clamp lock installed at the moveable V

Clamplock components. This is the clamp lock before assembly. It has to be installed on site at the turnout