Specific diesel trains

Train emissions may vary depending on local geographic and climatic conditions as well as operational factors such as station spacing, stop frequency and speed regulations. This category currently contains only models of train for which emissions testing has been carried out in the UK, and therefore users should consider the applicability of these data for train-based travel in other regions.

To use this category, select the geographic region and train model via the region and type drill options. After specifying the train type, set the distance travelled using the distance profile item value. The returned value represents CO₂ emissions for a single passenger journey (of the specified distance) using the default assumption of 31% train occupancy (see here for details of this default value).

Train occupancy

Users can optionally override the assumption of 31% occupancy by using the occupancy profile item value which should be set to a value between 0-100 representing the actual or estimated proportion of the train occupied. If the the occupancy profile item value is set to a new value, Discover recalculates the per passenger CO₂ emissions factor to reflect the sharing of total vehiclular emissions among the number of passengers travelling.

Accountable passengers

Users can also optionally choose to calculate emissions for a multiple number of passengers. To specify multiple passengers, set the the passengers profile item value to the number of passengers under consideration. The returned value represents CO₂ emissions for all passengers for the specified distance. If no value is set, Discover assumes a value of 1, i.e. a single passenger journey.