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Using gauge clearance assessments to understand the available space on the railway, D/Gauge have successfully supported the industry for the last 15 years

Working on various projects such as new train designs and introductions, vehicle cascades, vehicle modifications and infrastructure and electrification projects – D/Gauge’s software is now also a trusted tool for many of the industry’s engineers. The railway system represents a complex physical ecosystem that intertwines various components to enable the seamless movement of trains and passengers. Over the years, as upgrades and modernisation have taken place, the demands placed on the available railway space have  significantly increased. This surge in demand necessitates careful consideration of gauge clearance, which is crucial to ensure that all physical aspects of the railway can coexist harmoniously.

What is Gauge Clearance?
Gauge clearance in the railway refers to the amount of space (or clearance) provided between the vehicles and the surrounding structures or assets along the tracks. It ensures that there is sufficient space for trains to pass through safely without any obstructions or clashes.

The primary purpose of gauge clearance is to maintain a safe distance between the trains and various elements near the tracks, such as platforms, bridges, tunnels, signals, overhead lines, and adjacent tracks. It is essential to ensure the safety and smooth operation of the railway system.

Gauge clearance is determined by the specific railway standards and regulations of each country or region. These standards specify the minimum distance required between the train and the nearby structures to prevent any potential interference or accidents. The clearance is typically measured spatially to accommodate the various dimensions of trains, including width, height, and any lateral movement they may have while passing through curves.

Overall, gauge clearance plays a critical role in maintaining the safe and efficient operation of trains within the railway network by providing the necessary space and clearance for their movement while ensuring the integrity of the surrounding infrastructure.

How can gauge clearance be used across the rail sector?
D/Gauge can offer clearance assessments for the rolling stock, infrastructure, and electrification markets. Whether looking at it from a vehicle or an infrastructure perspective, there is space to be found around the entire network. Typical gauging is conservative and works for most scenarios, though the commissioning of detailed gauge clearance assessments can be the deciding factor for many projects.

Using gauging, asset owners and contractors can understand the impact of proposed works, the extent of modifications required to improve clearance, and the potential costs. There are essential questions for Project Managers, Infrastructure Managers and Design Consultancies to ask, for example:

  • Identification – Am I looking to identify structures which have tight clearances?
  • Investigation – Do I need to analyse what is causing tight clearances, or causing clearances to change?
  • Redesign – Should I need to consider clearance when redesigning track or structures?
  • Routing – Do we need to assess temporary vehicle movements, or out-of-gauge traffic?


Rolling Stock
D/Gauge support the Rolling Stock community with clearance studies during new train procurement, train introductions and retrospective modifications. When considering freight traffic DGauge are able to assess clearances of out-of-gauge loads.

There are some key questions that vehicle manufacturers, Rolling Stock Owners and Train Operating Companies can consider. These include:

  • Procurement – Am I currently procuring new train fleets?
  • Introduction – Will we be introducing a new train fleet, and need the assurance that it will fit?
  • Modification – Are we planning modifications to existing fleets that could change the vehicle shape and mass?
  • Freight – Do I want to run a freight load that does not conform to the route freight gauge?

The electrification community can utilise clearance studies to investigate electrification feasibility, design, monitoring and dewirement assessments. As the UK looks to extradite its electrification schemes, D/Gauge has been able to apply its innovative methods and technologies to help an electrified network become the reality.

For OLE Installers, Electrification Projects and Alliances, or design consultancies, clearance should be considered by asking:

  • Feasibility – Am I looking to retrofit overhead electrification into existing infrastructure?
  • Design – Do I have to design for structures with tight or unacceptable electrical clearances?
  • Monitoring – How do I monitor my overhead network for de-wirement risks and minimum electrical clearances


Onto the next chapter
D/Gauge has been leading the way in gauging techniques and technology for the past 15 years, consistently pushing the boundaries and developing innovative methodologies. The commitment to research and development remains unwavering, and heavy investment has been made in advancing gauging capabilities. Excitingly, D/Gauge has recently unveiled new methodologies specifically tailored for light rail environments and anticipates releasing these to software users later this year.

Collaboration has been integral to this success story, as D/Gauge has forged strong partnerships with various stakeholders and suppliers across the rail sector. Moving forward, there is an eagerness to build upon these collaborations, leveraging the collective expertise of industry players. One noteworthy partnership is with Cordel, a renowned specialist in infrastructure data capture, processing and management.

Together, D/Gauge and Cordel offer a comprehensive gauging and clearance management service, capitalising on combined strengths to deliver a seamless solution. A prime example of the benefits of a collaborative approach is with an ongoing project with Amtrak in the USA, where they are spearheading a complete modernisation of their clearance calculation and assessment processes. The focus is particularly on accommodating out-of-gauge, or ‘high and wide,’ freight traffic. D/Gauge hopes to extend its support to other international networks, contributing expertise and solutions in a similar manner.

In line with a commitment to sustainability, D/Gauge is actively involved in supporting decarbonisation efforts, specifically in the field of electrification. With the need to incorporate additional infrastructure in limited spaces for full electrification in the UK, the engineers have successfully challenged conservative gauging practices.

By introducing Probabilistic Gauging during the feasibility and design stages, the need for extensive physical interventions has been minimised, resulting in substantial cost savings amounting to millions of pounds.

In recent times, skills have taken clearance beyond national borders, with projects spanning Europe, North America, and Australia. As D/Gauge continues to explore international opportunities, it is eager to share the unique expertise and knowledge developed in the UK’s gauging domain with the rest of the world, fostering innovation and progress in the global rail industry.

Tel: 01332 972360,
Address: 11 Brunel Parkway, Pride Park,
Derby, DE24 8HR