Seamless Interchangeability

Seamless Interchangeability (SI) represents a radically new railway transport operational concept. The SI concept involves the running of a non-stop train, known as the prime train between terminal stations. To serve intermediate stations, autonomously powered carriages couple/uncouple from the front/rear of the prime train. For example, consider a typical 10 carriage train departing from London St Pancras and travelling to Sheffield. A percentage of the prime 10 carriage train will consist of passengers travelling between the terminal stations. As introduced above, the prime train does not stop at intermediate stations. Carriages uncouple from the rear of the prime train to serve intermediate stations e.g. Leicester. With trains from intermediate stations e.g. Leicester, coupling at the front of the prime train. Thus, allowing passengers to travel from an intermediate station and join the ‘quicker’ non-stop prime train. Effectively, the concept allows passengers to transfer between coupled trains, as a result, avoiding the need to change trains at stations. The aim of SI is to deliver reduced cost and carbon emissions, and increased customer satisfaction and capacity of the railway, as outlined in the Railway Technical Strategy 2012 (RTS 2012) i.e. namely on the ‘4Cs’. It is expected these deliverables can be achieved through the SI concept by freeing up latent capacity, thereby increasing network capacity, reducing journey times and as a result, reducing carbon emissions through lower energy consumption. To demonstrate the concept, a baseline mathematical model of a representative section of the Midland Main line was established. The model is based on the European Rail Traffic Management System (ERTMS) technology Level 3. The model delivered quantified outputs relating to defined key performance indicators (KPIs). The baseline model was then used in subsequent phases to evaluate the potential benefits of Seamless Interchangeability. SI delivers on the RTS 2012 i.e. the ‘4Cs’. Increased customer satisfaction is realised through fewer changes/stops, hence reduced journey times are achieved. The SI concept allows the number of carriages to be increased on the network, as a result of increasing network capacity; the customer satisfaction is also improved. With fewer stops for the ‘quicker’ non-stop prime train, both the cost and carbon emissions (energy usage) are decreased.