Specific electric 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 models of train for which emissions testing has been carried out specifically in UK-, Scandanavian- and Japanese-based contexts, 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 parameters. After specifying the train type, set the distance travelled using the distance parameter. 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).

Accountable passengers

Users can also optionally choose to calculate emissions for a multiple number of passengers. To specify multiple passengers, set the the passengers parameter 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.

Train occupancy

Users can optionally override the assumption of 31% occupancy by using the occupancy parameter which should be set to a value between 0-100 representing the actual or estimated proportion of the train occupied. If the the occupancy parameter 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.

Changing the country

By default, Discover uses the electricity-generation CO₂ emissions factor for the UK, but users have the option of specifying the country of their electric train travel, in which case Discover will apply the CO₂ emissions factor for electricity-generation appropriate to that country. To specify the country, set the country parameter to either the name of the country or the ISO code. For example:

• country=Italy
• country=IT

As described above, if no country parameter is specified, the UK emissions factors are used by default. If calculations are stored using profiles, the country can be specified within the profile metadata. Users should note, however, that directly specified country parameters override any set as profile metadata. This is useful, for example, for recording journey's outside the user's own country.