With the objective of assisting Network Rail to understand and assess the potential risks related to trains coming to a stand on arrival at Stoke Gifford Depot from the West, Hitachi was able to analyse train movements entering and leaving. There was significant concern that the mainline could be blocked due to the positioning of the new overhead line (OHL) neutral section at the emergency connection.
A model was built to simulate and record all potential combined signalled movements with train movement data modelled on the Class 800 and 802 IEP fleets. A new dessan Model was created with a simulated pantograph 21m from the rear of the train with the neutral section simulated as 51m long, the worst case scenario if a train were to lose power from the edge of the activation points.
The train units simulated were a 5 car Class 800/802, a 9 car Class 800/802 and a 10 (2x5) car Class 800/802.
The model assumed that:
- When entering the neutral section from the depot the train is able to accelerate up to 15mph as soon as it passes SBL1535 signal
- When entering the neutral section from the mainline, the train is slowing down to be travelling 5mph when its head gets to G44 ground signal
- Hitachi provided acceleration curves and coasting rates which were based on resistance values
The analysis found that all trains potentially using the emergency crossover would be able to traverse the section of line safely and not impact safety or performance of the mainline or the depot.