The main idea behind this leaflet has been to develop a small number of targeted, standardised and
effective functional indicators able to be implemented by all railways.
A functional indicator measures performance compared to the function the service brings to
customers/society: transporting people and goods over a distance. Functional indicators ensure
comparability between modes of transport by using the same reference as a denominator:
"passenger-km" and "tonnes-km" (see point 5 - page 33).
The key indicators describe the most relevant environmental impact of daily rail operations (traction
including shunting) which can usefully be compared with other modes of transport (except for indicator
"1.1 Specific final energy consumption" (see Glossary - page 39) which is only suitable for internal
use). This leaflet, its methodology and chosen system boundaries reflect the fact that each indicator
must be applicable for all transport modes in order to be compared.
Using this leaflet in connection with the UIC Guidelines for environmental indicators (see Bibliography
- page 42) will give further details on indicators for other key environmental areas such as waste and
material use as well as impacts which are not directly caused by traction (in stationary processes e.g.
maintenance facilities).
The chosen approach in this document does not allow focus to be laid on those sustainable aspects
relating to economic and social issues. The development of appropriate sustainability indicators for
railways will be addressed in forthcoming publications in line with developments within the field.
The environment "pillar" of sustainable development in transport addresses mainly:
- Higher energy efficiency: decreased energy consumption per delivered transport unit (see
Glossary - page 39),
- Increased use and share of renewable energy sources (for both diesel and electric traction),
Decreased impacts from air pollution and greenhouse exhaust gas emissions,
- Decreased noise emission levels, with the main focus their impact on citizens,
- Reduced land take and reduced impacts on the natural environment.
Consequently six environmental themes have been identified, leading to the proposal of six core
ndicators covering the most important environmental areas for railway operations and for the
transport system as whole (see also table land Fig. 1 - page 4):
Table 1 ~ Overview of the six indicators described in this leaflet and their use
In Figure 1 - page 4, the scope of the leaflet is described in the form of a diagram showing that all the
indicators relate directly to traction or railway production, and that no stationary processes are
included. The four blue boxes contain all six indicators.