Efficiency Improvement of Track Measurements

Project name: Efficiency Improvement of Track Measurements
Project manager: Milan Horemuz, Department of Real Estate and Construction Management (RECM), KTH
Other participants in the project from KTH:
Participating universities/companies/other organisations: RISE, Trafikverket
Financing: Trafikverket
Project period: 2026-07-01 - 2030-07-31

Today, the track position is determined using terrestrial geodetic methods, e.g. leveling and total
station measurement. These methods are time-consuming and require physically marked reference
points. The reference points need regular maintenance, and there is a risk that they may not remain
stable over time. To create better opportunities for efficiency, automation, and reduced maintenance
needs, Trafikverket (The Swedish Transport Administration) would need to make a structural change
by switching the reference for position indication. The change that needs to happen is to switch the
physically marked reference points to a satellite-based reference (GNSS). This would increase and
clarify the focus on Trafikverket delivering value to industry stakeholders and, at the same time,
simplify both our Trafikverket’s and the industry's daily operations.
Evidence that a GNSS-based reference for positioning cannot yet be directly applied in the railway
environment is that neither Trafikverket nor any other railway administration in Europe is currently
using it. However, there is rapid technological development in areas such as automation, which
means that the potential benefits of a GNSS-based reference are growing. We therefore believe that
the time is right to take the next step toward a GNSS-based reference.
To enable this shift, Trafikverket and the industry need to gain more knowledge. This could be
achieved, for example, by bringing together the country's geodetic expertise in a project; partly
through a doctoral project at KTH (Royal Institute of Technology), with supervisors from KTH, RISE
(Research Institutes of Sweden), and Trafikverket, and partly through research on GNSS
measurements in "electrical environments" at RISE.
The project will study the following research questions:
1. Mapping of:
a. Existing differences between the Trafikverket’s implementations and Sweden's national
implementations of geodetic reference systems.
b. Existing methods for modeling and managing the differences between a physically realized and a
GNSS-based geodetic reference system (current state analysis).
2. Analysis of point 1 above:
a. Do we have the same or different conditions to obtain homogeneous results between terrestrial
and GNSS measurements depending on where in the railway facility we are?
b. Is there a need for further development of existing methods?
3. Identify and describe problems and solutions with GNSS measurement in railway environments.
("Challenges and opportunities with GNSS").
4. Evaluation of measurement uncertainty requirements in the Swedish Transport Administration's
regulations:
a. Where do the tolerance limits for measurement uncertainty come from?
b. Are they reasonable? Do they meet the needs?
c. How is compliance – are they being met?
5. Is it possible to meet the Swedish Transport Administration's tolerance requirements (for railways)
with GNSS measurements?

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