Air Quality Directive

The Air Quality Directive 2008/50/EC of 21 May 2008 sets limit values for the concentration of some toxic matters. The most relevant of them for railway transport are particulate matters (PM) and nitrogen oxides (NOx). If the concentration of the regulated pollutant matters exceeds the limits on too many days of a year, the authorities are obliged to develop and execute Air Quality Plans.


Equipment needed to operate the traction equipment, but not producing tractive or
dynamic braking efforts themselves (e.g. cooling fans, oil and water pumps, and compressor).
In the context of this standard, heating and/or air conditioning of the leading
driver's cab is included in the auxiliaries (see UIC/UNIFE TEC REC 100 001).

Awarding, Awarding procedure

Procedure in which the right or the contract to operate public passenger transport
services on a particular route, network or in a particular area, is given to a transport
company by a competent authority (PTA). It is also the procedure used by a
competent authority to buy investments goods (like rolling stock). Awarding can
be done through either competitive tendering, direct awarding or through in-house
provision, although in certain cases legal restrictions by European or national law
apply when choosing the awarding method.


A cluster is a group of technologies or operational measures that are developed or
used with the same or similar objective in terms of reduction of energy consumption.
The definition of clusters is a heuristic method to analyse objectives and potentials
of different approaches. The technologies and operational measures that
are grouped in a specific cluster may be competing or co-acting with each other. A
cluster may consist of many elements (technologies/measures) while other clusters
may consist only of one element.

One example for a cluster is the recuperation of "braking energy” which might be
done with different methods, especially when it comes to diesel operation. Another
example for a cluster is "Eco-driving/driver training” to which several, partially coacting
elements belong.

Comfort systems

All equipment that consumes energy, but belonging neither to the traction equipment nor to its auxiliaries, mainly in passenger cars: heating, air conditioning, toilets, information and entertainment systems, laptop supplies etc. (see UIC/UNIFE TEC REC 100 001).


Any benefit, particularly financial, granted, directly or indirectly, by a competent authority from public funds to a transport operator who signs a public service contract with the PTA. The compensation usually covers the net financial effect on costs incurred for the transport operator in complying with the public service obligations or the tariff (fare) obligations plus a reasonable profit. Any overcompensation is not in compliance with European law.

Competitive tendering

Awarding procedure where the competent authority (PTA) may evaluate the offers of a number of interested transport operators or rolling stock providers in a public and transparent way. According to the EU law, three different procedures may be used: open, restricted or negotiated with publication of a contract notice. In the open procedure an invitation to tender is published and every interested company may take part and submit offers; in a restricted procedure tenders may only be submitted by the operators selected and invited by the PTA following pre-defined criteria; in a negotiated procedure with publication of a contract notice, the PTA chooses the companies to negotiate the awarding from among those that have answered to a public invitation.

Contracting out

The decision by a PTA to provide a public transport service through an external operator. A public service contract has to be signed between the PTA and this operator. The operator can be chosen by competitive tendering or directly.

Decibel (dB, dB(A))

Analyses of railway noise usually refer to sound pressure levels. The physical unit of measurement for sound pressure levels is "Pascal”. Human sound sensitivity acts approximately in a logarithmical manner. "Decibel” (dB) is a mathematical unit that is used in order to describe noise pressure according to the logarithmical manner of perception. An important characteristic of the logarithm is that difference values occur as follows:

• ΔL = 3 dB → the original physical quantity is doubled or halved respectively. A 3 dB sound pressure difference level can typically not be identified by humans;

• ΔL = 10 dB → the original physical quantity is decupled or reduced by a
tenth respectively. This difference is perceived by humans as a (subjective)
doubling or halving of the sound level respectively.

Acoustic signals are always composed of dynamic signals made up of (usually) many frequencies. The human ear has the highest sensitivity in the frequency range from approx. 200 Hz to approx. 10 kHz. Therefore, the originally measured signal must be 'frequency-weighted' when the effect on humans is to be described. Usually the so called "A-function” is used for this purpose and the weighted signals are marked as dB(A).

In railway acoustics, an important sound level is the LpAeq,T. It means an A-weighted sound pressure, equalized at the complete pass-by Time of a train. For example, the European sound limits for train pass-by measures given in the TSI Noise are quantified in this level. Further common levels are maximum levels, LAmax. Noise values given in dB(A) can only be compared if they refer to the same definition of sound levels and if they are measured under the same conditions (for example height, number and distance of measurement points, pass-by speed).

Direct awarding, direct contracting

Awarding procedure where the PTA awards the public transport services to an operator without competitive tendering. The details are negotiated directly between the PTA and the TOC. Even for this procedure the PTA is requested to publish a contract notice. Unless prohibited by national law, the use of direct awarding is an optional choice for the competent authorities for rail services (other than metro and tram) while for other passenger transport modes this is only allowed under special circumstances (see EU regulation 1370/2007). All compensation, of whatever nature, connected with a public service contract awarded directly shall also comply with the provisions laid down in the Annex of EU regulation 1370/2007.

Direct indicator, direct performance indicator

In the context of ECORailS, a direct indicator shows directly the energy consumption of a traction unit in relation to a unit of measurement that refers to transport or operational performance. The unit of the enumerator is "kWh” (kilowatt hours) while the denominator is given as:
• pkm (passenger kilometre); or
• seat km; or
• train km; or
• gross tkm (gross tonne kilometre).
In order to get meaningful results when comparing the energy consumption of, for example, different types of trains, it is essential to make sure that the secondary conditions are harmonised to a sufficient extent. Among other things, the following secondary conditions may be considered: timetable, gradients, ambient conditions, curves, occupancy, comfort functions and passenger comfort definitions.

EE/ENV criteria

Energy efficiency and environmental criteria are key elements for a sustainable transport policy. These criteria in awarding processes force bidders or directly contracted TOCs to propose means or services with less energy consumption or less emissions. Binding or encouraged inclusion of such actions reduces the specific energy consumption or provides better performance for the same energy input, cuts specific energy supply costs, increases competitiveness, reduces greenhouse gas emissions, the local air pollution and noise nuisance. Because of their considerable relevance, the ECORailS project focuses on energy efficiency, CO2 emissions, exhaust pollutants and noise although further dimensions of EE/ENV criteria might be considered.

Electric power supply

Generation and distribution of electric energy to the train: power stations, high voltage transmission lines, substations and their switchgear, catenary lines (see UIC/UNIFE TEC REC 100 001).

Environmental Noise Directive (END)

The Directive 2002/49/EC from 25 July 2002 requires authorities and member states in certain regions to measure and map noise pollution as a public service. Noise action plans are to be drawn up, based on these assessments, if certain immission limits are exceeded. The directive currently specifies which information is to be provided about noise pollution.

Gross tonne kilometre (gross tkm)

It is obtained by multiplying the gross tonnage of a train by the number of kilometres covered. The weight is generally determined by adding the weight of the load to the actual weight of each vehicle. If the train consist is modified during the journey this must be reflected in the calculation. In case of passenger transport a notional weight for the "payload” should be used. (See also UIC Leaflet 410!)

Guarantee of re-use (of rolling stock)

Guarantee of re-use is an option for dealing with the issue of rolling stock in different contract periods. The PTA guarantees the TOC the re-use of its vehicles in upcoming contract periods even if the respective TOC does not win the follow-up contract for rail services. Thus the risk of re-use is removed from the TOC, with benefit for the vehicle factoring. At the end of the period the vehicles will be assigned to the winning TOC and the "old” TOC will receive compensation, usually the fair value of the vehicles at the end of the first contract period.

In-house provision

It is a special case of direct awarding where the public transport services are
awarded to an internal operator. An internal operator is a legally distinct entity over
which a competent local authority, or in the case of a group of authorities, at least
one competent local authority, exercises control similar to that exercised over its
own departments.

Indirect indicator

In the context of ECORailS, an indirect indicator describes a parameter that has a major or substantial influence on the energy consumption of a train but does not describe the energy consumption itself. The most prominent example is "mass per seat” which can be used for the procurement or description of passenger carriages for loco-hauled trains.


Fixed installations of the railway: tracks, power supply, signalling, communication
etc. (see UIC/UNIFE TEC REC 100 001)

Integral regular timetable (ITF)

Regular timetable with the additional quality that at all major nodes of the railway
network trains from all directions arrive at a short time before minutes 00 or 30 of
every hour and depart a short time after. Thus optimal connections are provided for
passengers from and to all directions.

Loco-hauled train

The traditional passenger train comprises a collection of coaches with suitable motive
power attached in the form of a locomotive. As long as the train weight remains
within the capacity of the locomotive(s), any number of vehicles can be attached,
although limits will be imposed by platform or siding lengths. Locomotives themselves
can also be used flexibly, many being designed to cover a range of duties.
In spite of that, multiple units may be more appropriate for a range of passenger
operations, depending on the kind of flexibility needed.

Multiple Unit (MU)

A powered train (or part of the train) of fixed consist (group of vehicles coupled
together). The fixed consist of a multiple unit comprises both passenger compartments
and propulsion aggregates. Depending on the type of services and the actual
design, MUs may have advantages in terms of flexibility, better acceleration
and more efficient recuperation of energy when braking.

Net present value (NPV)

Net present value (also present value) is used for dynamic cash-flow statements
in order to compare capital costs during different time periods. The comparison is
enabled by discounting upcoming cash-flows on the starting point of the capital

Operational measure

Operational measures aim at achieving a more energy efficient use of existing
vehicles and infrastructure. Operational measures can be applied independently
of the type and age of the rolling stock, although the actual effects may differ. The
most prominent example is "energy efficient driving”. Operational measures may
require the fitting of additional features to the rolling stock, e.g. energy meters, or
certain control functions, but these can usually be fitted without major changes to
the vehicles.

Operational performance

In case of passenger railway operations: Figures to describe quantitatively the
services that are provided, but independent of the occupancy rate. Main parameters:
seat km, train km, gross tonne km.

Public service contract (PSC)

The PSC is the legally binding act that confirms the agreement for a specific rail
service between the two contractors, PTA and TOC, and in which the competent
authority requires the public service operator to comply with quality standards and
technical specifications. The PSC must be in accordance to national law, but the
actual standards and requirements may be stricter, e.g. in terms of environmental
effects, than required by national or European legislations. The requirement concerning
standards and techniques also has to be included in the tender documents.

Regular timetable (clock face timetable)

A timetable in which trains that belong to the same route are scheduled with fixed,
periodic time intervals between their train paths.

This timetable is based on two fundamental elements:
• Standardisation of routes, stops and running times
• Repetitive schedules (trains follow each other at regular intervals).


Criteria that the TOC or the manufacturer needs to fulfil as minimum standards in
order to be qualified for the contract. The fulfilment must be verified and monitored.
Bidders that breach the minimum standards will face sanctions that need to be
fixed in the tender documents or in the service contract in advance.

Rolling stock

All sorts of railway vehicles, with or without propulsion system, including vehicles
for passenger or freight transportation (definition by Railenergy)


Suppliers may develop different solutions for the application of the same technology.
One example is that more than one supplier offers super-capacitors for the
on-board storage of energy. Asking for a specific solution can be very close to asking
for a specific product and thus cause legal problems for a PTA issuing a tender.

Specific indicator

Different technologies or solutions that are implemented for the same purposes
may be compared by specific indicators. These indicators must be defined individually
for each cluster or technology. For example, if different technologies for recuperative
braking are to be compared, the recuperation rate (recuperated energy
compared to the overall traction energy) may be used. Operational, ambient and
infrastructural conditions should be harmonised for this purpose.

Specific service profile

A specific service profile describes the characteristics of a real line or network,
such as gradients, curves, distances between stations, timetable and maximum
track velocity. The more exactly these characteristics are described the more precisely
the energy consumption needed for traction effort when driving on this line
or network (see also "standard service profile”) can be calculated.

Standard costs

An estimated or predetermined cost level of performing an operation or offering a
service, under normal conditions. Standard costs are used as target costs (or the
basis for comparison with the actual costs), and are developed from the analysis
of historical data or from time and motion studies. The standard costs of energy
consumption of regional train operations may be analysed separately from other
types of costs. Standard energy costs can be used, for example, as a calculation
basis when compensation for cost increases is concerned.

Standard service profile (SSP)

A standard service profile describes the characteristics of a virtual line. The UIC/
UNIFE Technical Recommendation 100 001 ( defines
such service profiles. The SSPs "Suburban”, "Regional”, and "Intercity” are
relevant for awarding regional passenger services or the respective rolling stock.
Due to the fact that the calculated energy consumption of a train on these virtual
lines is not to be directly compared to the energy consumption of a train on a specific
line, the standard service profiles should only be used to compare different
vehicle designs on a standardised basis, independently from a concrete network.
This approach is similar to standardised test cycles in the automotive industry.


Equipment of vehicles or the infrastructure. Technologies for reducing energy consumption
typically require investment costs while saving operation costs during the
lifetime of the equipment or the vehicles. The analysis of promising technologies
and operational measures is relevant for PTAs in order to estimate reference levels
or reduction potentials. Additionally, it may be appropriate to require or to encourage
certain technologies in awarding procedures under certain circumstances.

The quality and performance of technologies can be described by specific performance
indicators. These indicators must be defined individually for each technology
and can refer to its specific contribution and efficiency in terms of energy consumption,
noise or exhaust emissions.


A proposal made by a transport operator in response to a call published by a PTA
in case of competitive awarding. The tender must follow the requirements that are
given in the call and in its annexed documents. The time limits enclosed in the
awarding documents must not be exceeded.


Short for competitive tendering

Traction equipment

Equipment directly needed to produce tractive or dynamic braking effort (e.g. transformer,
converters, motors, gearboxes) (see UIC/UNIFE TEC REC 100 001)

Traction unit, tractive unit

One or several railway vehicles with a propulsion system (definition by Railenergy)


Consist of one or more vehicles, including at least one traction unit, all coupled and
running together.

Transport performance

The transport performance of passenger services is the number of passengers
multiplied with the distance over which every passenger has been transported.
The unit of measurement for the passenger transport performance is "passenger
kilometre” (pkm).