ProRail is responsible for the maintenance and operation of the rail network in the Netherlands. They boast an incredibly busy rail network: 7,000 kilometres of track, 2,500 crossings, 7,000 railroad switches, and 400 railways stations.

The challenge

Being responsible for the maintenance and operation of the rail network means that ProRail needs to control every single aspect of the infrastructure. In order to achieve this, ProRail makes use of technical drawings that describe each aspect of the infrastructure.


Part of this infrastructure is railway signalling. Railway engineers use specialised software to create and validate all technical drawings in this area. For example, the software helps checking whether the drawings meet the comprehensive and rigorous drawing and design rules. This software is where SIG was specifically involved in.


ProRail makes use of the services of RIGD-LOXIA, a company that develops the software to make and modify the drawings for railway signalling. However, the responsibilities of this software and the resulting drawings were far-reaching: security, safety, operational costs—there was a lot at stake.


There was also a need to change the foundation of the software, but that was only possible after achieving a substantial higher quality level. ProRail and RIGD-LOXIA needed to ensure the software was of the highest quality to achieve their goals, and SIG was asked to help with the quality assessment and improvement.


The solution

ProRail, RIGD-LOXIA and SIG jointly de ned goals and metrics to track progress. Examples of such goals are reduction of legacy code, improved code quality and way of working, and adherence to a new software architecture.

“First our developers were skeptical about SIG. They were afraid of meddling and undermining their autonomy, but after several sessions they felt helped and became more interested. They experienced their software became better. The adversarial sessions were very important in this. Now they are actively pursuing software quality.”

Nico van Didden, Project Manager, ProRail

The original software was poorly maintainable, which was a risk giving the safety implications. In recent years ProRail worked hard to deliver “first-time-right” software, and with success: “New features are delivered at once, first-time- right, whereas in the past several fixes were necessary for a flawless release.” This means a huge efficiency improvement. Maintainability is instrumental here, because checks need to be quickly and accurately added and adjusted to the software.


SIG’s assessment did not just measure the quality of the software, but the score itself also served as a motivating catalyst among staff. In addition, it sets a standard for new potential employees: “It is also striking that candidates sometimes withdrew when they became aware of our high- quality standards during a job interview.”


As a result of the cooperation between ProRail, RIGD-LOXIA and SIG, the management of ProRail/RIGD-LOXIA is now convinced that:


  • Code quality can be controlled.
  • High quality really impacts costs and time-to-market.
  • Quality awareness leads to employees who are proud of their work.
  • High quality standards attract better qualified employees.


  • Significantly less errors in releases and increased pace of delivery with same capacity.
  • Fostered higher level of quality awareness of developers.
  • Higher job satisfaction and increased motivation of developers.
  • Improved development process.
  • Increased code quality.
  • SIG delivered a high-quality report analysis in which you really see that this is their core expertise. Based on facts and their extended knowledge of software quality they provided clear advice for further improvement.
    Hidde Andriessen CIO Office at KPN
  • In assessing a vendor for a critical software purchase, TÜViT told us that SIG was the only one organization certified to determine if (1) the purchase was a good foundation for future excellence (2) it was worth the investment (3) it could integrate it seamlessly into our own organisation. We wouldn’t hesitate to work with SIG again.
    Markus Hölzlein General Manager Digital Products at Weltbild GmbH
  • The work with SIG was very beneficial for our due diligence and helped us in the decision making process. The combination of deep technological understanding and the necessary pragmatism when looking at early stage companies proved very value adding for us and also for our target company.
    Christian Knott Partner at Capnamic Ventures
  • SIG’s work is crucially important for Waternet as we elevate our online services. This digital era demands new ways of thinking about software in terms of technology, vendors and operational issues, and SIG guides us in all three areas.
    Mario Kortman Director Digital Transformation at Waternet
  • With the help of SIG we brought the software quality to the next level which helps us to deliver our installations faster.
    Yvo Zethof R&D Project Manager at VanRiet
  • The SIG toolset has enabled us to gain valuable insight into the code quality of potential acquisition targets, thereby enabling the company to make decisions based on quantitive measures rather than subjective opinion.
    Arun Mundray CTO at Kallidus
  • For our major risks in large scale development with or without partners we turn to SIG to set the benchmark for quality delivery and improvements of the code base. Their professionalism in these matters certifies the long term sustainability of our software assets and as such our investments.
    Carl Tilkin-Franssens CIO at Acerta
  • SIG triggered a behavioural change. The assessment did not just measure the quality of the software, but the score itself also served as a motivating catalyst among developers. Now developers actively pursue high quality software and continually improve upon their skills.
    Nico van Didden Project Manager at ProRail