Erex terminology

Check our most used terms herunder

Application Programming Interface (API)

A software interface that enables applications to communicate with each other. An API is a set of programming language that can be coded in an application program to obtain the specific functions and services provided by an underlying operating system or service program.

Area parameters

Area parameters are attributes that are specific to individual geographical areas or types of areas.
Example of a possible use for this is area-specific fees.

Beta testing

Pre-release testing in which a sampling of the changes/new functionality/bugs correction is tested.

Calculation input data

The calculation input data set is the sum of all raw, preprocessed and consolidated input data and parameters for a settlement procedure and period.

It must be possible to document all parts of the calculation input data set that were used in a settlement, by backtracking from a final invoice. Once a data set has been consolidated and used for settlement, all additions or corrections to the data must be applied as incremental changes without overwriting the original data.

Data from input data sets must be accessible for the component calculations through standardized interfaces.

Calculation results

Calculation results are the calculated money amounts and other results stored by the different settlement component calculation modules. Any number of calculations is stored into a common result set that is accessed as a unit when generating final invoices. Individual result amounts may be bound to customer, area, country and period. A standardized interface exists for storing calculation results.

Change Request (CR)

Any request from a partner representative or stakeholder to change an element or a process. Change Request documentation include: information on the origin and impact of the current problem, proposed solution, and its cost.

Consolidated input data

Consolidated input data are time series and parameters that are placed under version control and protected from overwriting. The intention is that such data should be reproducible just as they were at any given point in time.


UIC definition: Party that consumes electricity

Examples of consumers are Traction Unit Owners and Railway Undertakings.

Consumption area

Consumption area is the Grid Area of one Infrastructure Manager (IM). The consumption area is delimited by agreed border crossing positions published as part of the UIC leaflet 930.

Consumption factor

The consumption factors are multiplied with gross tons * km traveled to get an estimation of the used energy for unmetered trains.

Consumption point

A point where energy is consumed. One traction unit may have more than one consumption point, and more than one traction unit can be part of a train.

Consumption point administrator

UIC definition: Party responsible for administering consumption point characteristics and administrative data such as consumption point id and characteristics of the traction unit.
In Erex the Consumption Point Administrator is responsible for defining new consumption points and traction units, for assigning properties such as validation limits to traction unit types, and for administer ownership between organizations and consumption points.

Contracts with external suppliers

If train operators are allowed to purchase electricity from external suppliers, information about this must be available for the settlement calculations.


Costs are money amounts that are used as input parameters for settlement component calculations.
For example, a recurring fixed cost may be distributed across all customers that operate trains in a certain area. Erex relates costs to areas and periods.


An organization having an agreement with any of Eress partners (Jernbaneverket/Trafikverket/Banedanmark/Infrabel/Vivens/Liikennevirasto/SBB) to buy energy for various purposes (e.g. train traction, heating etc.).

Customer parameters

Customer parameters are settlement settings that are specific to customers or customer groups.

Data Collector

Party responsible for the reading of metered data, including location and quality control of the reading.

Data Responsible

UIC definition: Party responsible for:

  • Establishment and validation of metered data based on collected data received from the Metered Data Distributor
  • Estimation of unmetered data
  • History of metered data for local metering points
  • Substitution of values when necessary

In Erex the Data Responsible role is the party receiving the exported data (end results of Erex processing).
The Data Responsible role may apply for more than one consumption area.

Electronic Data Interchange (EDI)

EDI or Electronic Data Interchange is computer-to-computer exchange of business data in publicly published and globally standardized formats. The term is normally associated with UN/EDIFACT, but there are also other similar EDI standards.

Energy consumed by trains

Energy consumed by trains is the most central parameter of the settlement procedure.
Consumption is typically represented as Time series (sequence of numerical data points in successive order) with resolution ranging from 1 hour down to 5 or 1 minute.
Each meter reading needs to eventually be associated with a customer and with a geographical area.

Energy conversion factors

Train energy consumption may be estimated from gross tons * km traveled, using externally calculated energy conversion factors.
The energy conversion factors vary depending on train type and geographical area.

Energy regeneration

Some trains may produce electricity when braking, and this regenerated energy may be used in settlement component calculations.
Time series for regenerated energy will typically come from the energy measurement systems (EMS) along with consumption data.
Regenerated energy may be stored for each individual train or aggregated by customer.

Energy supplied

The energy fed into the railway supply system is an important part of the settlement calculations. It is represented as a set of Time series, typically measured with a resolution of one hour.
Energy supplied must be associated with geographical areas.

Entity in Charge of Maintenance (ECM)

An entity in charge of the maintenance of a vehicle, and registered as such in a vehicle register
[2016/798/EU – Art. 3 (20)]

Exchange rates

Costs and prices may be entered in any currency. Exchange rates should be available for recalculating amounts into settlement currency.

File transfer protocol (FTP)

FTP is a basic internet function that enables files to be transferred between computers. You can use it to download files from a remote, host computer, as well as to upload files from your computer to a remote, host computer. 

Final settlement results

Final settlement results in invoices based on calculation results and previous on-account settlements.
The settlement results also contain fees and taxes such as VAT that are applied at the invoice level.

Graphical user interface (GUI)

GUI is a type of interface that enables users to communicate with a program by manipulating graphical features, rather than by entering commands. Typically, a GUI includes a combination of graphics, pointing devices, menu bars and other menus, overlapping windows, and icons.

Infrastructure capacity

The potential to schedule train paths requested for an element of infrastructure for a certain period
[2012/34/EU – Art. 3 (24)]

Infrastructure Manager (IM)

any body or firm responsible in particular for establishing, managing and maintaining railway infrastructure, including traffic management and control-command and signalling; the functions of the infrastructure manager on a network or part of a network may be allocated to different bodies or firms
[2012/34/EU – Art. 3 (2)]


The ability of a rail system to allow the safe and uninterrupted movement of trains which accomplish the required levels of performance
[2016/797/EU – Art. 2 (2)]

Invoice estimates

Invoice estimates are used as basis for the On-account settlement.
As a settlement procedure may consist of several settlement components, an invoice estimate for that process may be broken down into separate estimates for each component.


The natural or legal person that, being the owner of a vehicle or having the right to use it, exploits the vehicle as a means of transport and is registered as such in a vehicle register
[2016/797/EU – Art. 2 (21)]

Local metering point

A physical or a virtual metering point. A Consumption point has a Local metering point for each Consumption area where it has access to consume energy.


A physical device containing one or more energy registers.

Meter train operator relations

Meters are mounted in trains.
A train may use several traction units and combination of traction units during a particular trip.
A traction unit may only be in one train, and accordingly having only one operator, at a time, however, over time the same traction unit may be associated with different operators.

Metered data distributor

UIC definition: Party responsible for breaking down and distribution of metered data according to location data information. It is also responsible for long term storage of consumption data.
In Erex the Metered data distributor role manages the validation and splitting process phases. The latter is where the consumption data is allocated to the different consumption areas according to the metered location values. This process decides which Data responsible should receive the metered data.

Metered time series

Metered time series contain the energy consumption readings from the meters on trains.
The metered values are associated with geographical areas either through GPS coordinates or through time series identifiers.


The lines, stations, terminals, and all kinds of fixed equipment needed to ensure safe and continuous operation of the rail system
[2016/797/EU – Art. 2 (4)]

Network Statement

The statement which sets out in detail the general rules, deadlines, procedures and criteria for charging and capacity-allocation schemes, including such other information as is required to enable applications for infrastructure capacity
[2012/34/EU – Art. 3 (26)]

Non-metered consumption data

Data representing the calculations based on gross tons * km traveled for a train or operator, accumulated by area and period, in the settlement system, see Payload.

On-account settlement

On-account settlement is an intermediate, temporary settlement based on predictions. The purpose of on-account settlement is to secure payment for goods or services as they are used, even if the exact quantities and amounts are not known until much later.

On-account settlement results

On-account settlement results in invoices are based on estimated amounts. One invoice may contain amounts for several settlement components.
In addition, the settlement results also contain fees and taxes such as VAT that are applied at the invoice level.

Other energy consumption

Not all electricity fed to the railway supply system is used for train traction. This must be considered when calculating losses or performing calculations that involve all consumption.
Time series for energy used by other consumers may be used in settlement component calculations.

Ownership (of data)

The undisputable right to manipulate, and decide who will have access to- and what happens to the data.


One of the backup solutions for collecting train consumption data is estimation based on payload.
For this purpose, the gross tons * km traveled for a train or operator, accumulated by area and period, must be stored.


Prices are time series data that may be used in settlement component calculations.
Examples of price types that may be relevant are electricity spot prices and imbalance prices.

Railway Undertaking

Train Operators that hold the role of Consumer. In many cases the Railway Undertakings will also be the Traction Unit Owner.

Railway Undertaking (RU)

Any public or private undertaking licensed according to Directive 2012/34/EU; the principal business of which is to provide services for the transport of goods and/or passengers by rail with a requirement that the undertaking ensure traction
[2012/34/EU – Art. 3 (1)]

Reconciliation Factor

The reconciliation factor is used to allocate the unallocated costs. By adjusting the reconciliation factor the unallocated costs will be placed on the consumption of the unmetered trains.

Result set

See calculation results. The result after a settlement procedure has been performed is called a result set. The result set has to be approved before used in a invoice.


Definition of behavior and responsibilities of an individual or individuals using Erex system.

Settlement procedure

A settlement procedure definition describes the properties of a cyclic settlement workflow.
Each settlement procedure comprises properties such as:

  • Settlement periods
  • On-account settlement frequency
  • Settlement components that are part of the settlement procedure
  • Invoice issuer role
  • Customers

Settlement process

A settlement process performs the calculations for a settlement procedure.

Settlement instance

The complete collection of data and resources related to one settlement country defined and running in the settlement system. This includes the definition of the settlement responsible, its customers, users, settlement procedures and processes.

Technical Specification for Interoperability (TSI)

A specification adopted in accordance with Directive 2016/797/EU by which each subsystem or part of a subsystem is covered in order to meet the essential requirements and ensure the interoperability of the Union rail system;
[2016/797/EU – Art. 2 (11)]

Time series

Sequence of numerical data points in successive order.

Traction unit

A physical unit capable of autonomous movement. A Diesel traction unit has no consumption points.

Traction Unit Owner

UIC definition: Party owning a traction unit used in international traffic.
In Erex the Traction Unit Owner is represented by the Customer.  A customer has access to the metered data and other relevant data concerning its settled energy.
According to the UIC leaflet 930 the Traction Unit Owner should have access to its 5-minute metered values in the same terms as the Customer in Erex.

Traffic Category

The type of goods carried by a train, for example cargo, passenger etc.
Train meter readings are expected to be accompanied by GPS coordinates. Erex settlement uses the coordinates to determine which country or area a train was located in when a meter reading was made.


In Erex system, Train includes distance, traffic type, weight and composition of the traction units travelling between point A and point B in a certain period of time. The term can be compared to the definition of “Flight” in the airline industry.

Train disposition data

The train disposition data contains, in addition to a description of the trains themselves, time table and delay information.
The train disposition data should tell us

  • Which company operated the train
  • Which meters were on that train
  • Time when that train left from or arrived to certain stations

Train Management System (TMS)

A Train Management System is responsible for keeping information about trains, i.e. the distance travelled, the time, the traffic type (cargo/passenger), the weight and the composition of traction units. This information is used by Erex system to collate metered data with train runs, and to decide whether or not to use the metered data or the reported payload for a train metering point (consumption point) in the settlement.

Train metering point

Train metering point is the same as a Consumption point. According to the UIC  Leaflet 930, the relationship between an energy meter and a consumption point is 1:1. A train metering point or Consumption point cannot be moved to another traction unit.

Train parameters

Train parameters describe attributes specific to train types or individual trains for applying fees to train operators or train types.

Train Path

The infrastructure capacity needed to run a train between two places over a given period
[2012/34/EU – Art. 3 (27)]

Uncorrelated time series

Uncorrelated metered time series contains “raw” metering values, i.e. values not connected to an operator or an area.
In order to associate the metered values with a geographical area, train disposition data may be used.


Object suitable for circulation on wheels on railway lines, with or without traction
[2016/797/EU – Art. 2 (3)]


eXtensible Markup Language. XML was designed to store and transport data.

You´re more than welcome to suggest other relevant terms to include on this page.
Use the contact form in the bottom of the page to send your suggestions to us. Thanks!


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