Transport Infrastructure Monitoring

Other considerations have grown in recent years with sustainability another big consideration. Energy useage and thermal performance of buildings is a growing concern. The need to save energy and costs is also driving new inspections such as thermal performance.

Organisations responsible for transport infrastructure assessments are a combination of public and private entities. Councils and DfT departments are the owners of road and rail infrastructure with commercial organisations mainly the owners of airports and commercial maritime ports infrastructure.  

The frequency of infrastructure monitoring varies but in most cases for transport it is at defined and spaced-out intervals covering weeks or months. The inspection intervals are specified in statutory requirements and regulations for many of the assets with the responsibility for funding and carrying out the inspections falling on the infrastructure owners and operators. Inspections are carried out as part of the assessment with remedial work prioritised and funded according to priority and criticality.

Technologies used in infrastructure monitoring are specified within some regulations, for example to inspect road and rail, specific vehicles are deployed with defined sensing technology to assess the health of the infrastructure using a variety of sensors which include radar, lidar, camera and accelerometers.

In addition to maintaining current infrastructure, new building projects such as HS2 and the Elizabeth Line experienced significant budget overruns with logistics and building efficiencies contributing to the high costs. 

Operating the significant road, rail, air and maritime land based infra structure is a huge challenge which costs a lot of money. Road and Rail infrastructure managed and operated by local or national government departments are under pressure to reduce costs, improve efficiency and safety. 

The challenge to maintain what is already in place is compounded by the addition of active travel and the addition of passenger support services. This creates a more complex environment to manage due to the interactions between the modes of transport and the changing use of the infrastructure.

Current practices for infrastructure monitoring and maintenance do not remove preventable safety issues, large maintenance repairs and crises from arising across transport infrastructure. The quality of repairs especially on roads is not regularly inspected creating variation in the life of localised road surfaces.

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Network Rail - New Measurement Train (NMT) - Network Rail

Established digital sensors on infrastructure or located on specialist vehicles can provide detailed data on objects and markings, using various high density data sensors such as cameras, radar and lidar. 

Weather, pollution, light and heat can be monitored using IoT sensors and structural integrity can be assessed using force, temperature, displacement, vibration, strain and electrochemical sensors.

Many new sensing technologies have also emerged, with recent examples highly relevant to infrastructure:

• Lidar (Laser imaging detection and ranging) - is used increasingly in infrastructure scanning as it produces accurate 3D images referred to as point clouds. This is more accurate than camera imaging for scanning complex shapes in detail and is being used to create the fine detailed maps used for driver assistance navigation maps and digitise buildings for example. 
• Aerial monitoring via drones and satellite imagery provides remote monitoring capabilities, making it easier to assess hard-to-reach areas. This is particularly useful for large-scale infrastructure like railways and maritime ports. 
• Fibre optic sensing includes Distributed Temperature Sensing (DTS), Distributed Temperature and Strain Sensing (DTSS) and Distributed Acoustic Sensing (DAS). These are types of optic sensing technologies which use the properties of light as it travels along a fibre to detect changes in temperature, strain and vibration. DAS can detect vibrations and pinpoint the source to a specific location along the length of the cable. This can be used on railways to detect rail line anomalies. This uses the trackside fibre optic cables already installed for comms and signalling to detect vibration when the train runs along the track. Impact when the wheel crosses joints and points create a vibration signature which can be monitored for change over time. The same technology can monitor geological phenomena (earth tremors and land movement), fatigue monitoring, thermal changes and leak detection as well as offering the opportunity to provide perimeter protection.

Mobile phones have been used recently as a low-cost way to scan road surfaces. This is a relatively simple repurposing of a developed technology to provide real time data using the inbuilt cameras and smart image recognition algorithms, useful to highways authorities in detecting road imperfections. Applying phones to vehicle fleets already covering the road network such as delivery or waste management vehicles, provides an ideal opportunity to collect the data required on a continuous basis.

Alternative scanning methods and products are being trialled across Road and Rail in particular. DfT is reviewing road condition monitoring and is introducing a new data standard that allows local authorities to choose technologies to suit their needs, as long as they align with the new standard. This shift is intended to encourage innovation and open the market to alternative technologies (Road condition data and technology review).

All the transport operators and infrastructure providers are looking for more efficient and effective ways to monitor their assets. A variety of very capable sensors, many of which are low cost, are transforming how infrastructure is monitored and maintained. The ability to mount these sensors quickly and transmit their data robustly using 5G communications provides flexibility and minimises installation effort and cost. 

The availability of robust 5G communications across all 4 modes of transport infrastructure to enable the monitoring and services discussed in this document is covered by separate advisory toolkits for each mode of transport. 

It is key to note that 5G upload speed and number of connections that can be supported on mobile networks are as important as download speeds for infrastructure monitoring. The volume of data transferred by camera, radar and lidar in real time is significant and the number of sensors being deployed is growing.

Recommendations and further discussion are focussed on 2 related opportunities:

Data sharing to enable efficient transport infrastructure monitoring and maintenance. Access to sensor data gives the transport providers as well as infrastructure operators opportunity to improve their services. This includes operators of vehicles, ships and planes that use the infrastructure. Data sharing provides an opportunity for innovation and rapid product improvement. Detailed work has already started to define standards for data to enable sharing in many areas of transport (see “intelligent traffic management” toolkit). There are European initiatives as well, such as SENSORIS where automotive, map providers and telecoms operators’ are collaborating (SENSORIS). Infrastructure monitoring data sharing across transport is a recommended discussion topic for DfT. 

Wider monitoring services using shared data – Sharing sensing data, enabled by the previous recommendation, will enable insights across an integrated transport system and not just for bespoke and narrow applications. The opportunity is to create greater capability and better outcomes using a collaborative sensor set through the shared data. This opportunity requires cross modal thinking to define the goals and opportunities and it should include transport operators, infrastructure providers and passengers. This is a future opportunity and will assist in DfT’s future Integrated National Transport System (INTS) initiative. 

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Rail (Network Rail Limited Annual report and accounts 2023)

Network Rail is responsible for managing and maintaining the rail infrastructure with the Office of Rail and Road (ORR) who oversees its performance and adherence to standards. Rail infrastructure and inspections cover:

• 2,578 stations excluding heritage and TfL underground.
• 20,000 miles of track 
• 64 intermodal rail terminals at docks and rail interchanges used for freight (Intermodal rail GB)
• 30,000 bridges, tunnels and viaducts.
• Depots and staff buildings.
• Drainage systems.

Airports (Regulations for air services in UK) :

Civil Aviation Authority (CAA) is responsible for regulating most aspects of aviation in the UK, including the safety and maintenance of airport infrastructure across airports. Statutory Inspections include:

• Runways and Taxiways: surface integrity and markings.
  • Lighting Systems: lights which indicate edges, routes and parking on the runway and taxiways.
  • Navigational Aids: equipment like Instrument Landing Systems (ILS) and radar systems.
  • Buildings, Terminals, bridges, baggage systems: compliance with building regulations.
  • Fire Safety Systems: maintenance of fire detection and suppression systems.
  • Drainage systems.

Maritime Ports (MCA inspection - GOV.UK, Ship security - GOV.UK):

Maritime and Coastguard Agency (MCA) oversees the safety and security of maritime operations, including port infrastructure to ensure adherence to the Port Marine Safety Code (PMSC). Statutory Inspections include:

• Ships: compliance with international safety standards.
  • Structural Inspections: docks, piers, and warehouses.
  • Navigational Aids: lighthouses, buoys, and other aids to navigation.
  • Environmental Compliance: waste management and pollution control.
  • Emergency readiness: fire and rescue.

Statutory inspections are crucial for maintaining the safety, security, and efficiency of all the key infrastructure across the 4 modes of transport. Quantifying the opportunity for improvement involves trying to scale the tasks and issues common todays across each mode:

• Annual UK car damage was £1.7bn due to ROAD potholes, in the latest report Kwikfit.
• The costs to operate and maintain the ROADS in 23-24FY was ~£2.1bn by LA’s, with a further £8bn provided by DfT for road condition upgrade (National Audit Office report, July 2024). Key findings from this report included:
  • There are currently significant gaps in DfT’s information on the condition of local roads, limiting its understanding of condition of the network. 
  • DfT does not consider the condition of roads or the factors that contribute to road deterioration when allocating funding to local authorities.
  • DfT needs to plan now for how it will support local authorities to meet challenges on the road network, such as climate change and the introduction of self-driving vehicles.
• RAIL carries 1.45 bn passengers and 15.7 bn tonne/km of freight and track and power lines are checked by Network Rail staff monthly by manual inspection using a “condition-based inspection” where monitoring is focussed on more heavily utilised assets. More detailed inspections are carried out using a measurement fleet which includes the New Measurement Train (NMT). The NMT uses cameras and lasers plus other tech on a high-speed train. 115,000miles are covered with the measurement fleet with the busiest lines being inspected more often during the year. (NMT).
• Network RAIL net operating cost in 22/23FY was £7bn. Cost efficiencies are targetted for each control period which are 5 years each. Employee safety improvements, service improvements, and reduction of staff accidents are key PFI which include working practice and monitoring of infrastructure. (Network Rail Annual report 2023). Station platforms, trespass, vegetation, drainage and level crossings along the lines are amongst surveillance priorities. 
• Commercial AIRPORTS in the UK which carry 226 million passengers and 2.0 million tonnes of cargo with significant buildings, baggage, cargo, runway and parking infrastructure (Compliance monitoring CAA) :
  • Airport runways and infrastructure are inspected to ensure safety and compliance with aviation standards. The CAA oversees this with guidelines set out in the Aviation Security Regulations and other relevant frameworks.
  • Runways are typically inspected daily, with additional checks after adverse weather or heavy traffic periods. These inspections include visual checks for debris, surface damage, and lighting functionality. Friction testing and structural evaluations take place monthly or annually depending on the airport.
• Commercial coastal MARITIME PORTS around the UK includes 400 non-cargo handling ports and 120 cargo handling ports. Annually inspections vary by the size of the port, operation and throughput of goods and people. 
• Cranes, gantries and automated systems are inspected along with the quayside infrastructure, buildings and navigation equipment.

Smaller ports have a narrower infrastructure portfolio and will be inspected less often.

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Image courtesy of Kwikfit

Prevention

Real-time data collection and analysis enables alerts to be raised if thresholds are approached or exceeded. Deterioration can be tracked over time so intervention can take place before critical failures are likely, this is key for preventative maintenance. Preventative maintenance is the best approach as it moves from catching a problem to being able to schedule maintenance work in the future based on expected deterioration to the point of needing repair. This allows for scheduled maintenance and better resource planning.

A good example of this is the monitoring of potholes in roads. If the road is scanned daily instead of quarterly or yearly, a road surface defect can be detected at formation and its growth can be monitored. This leads to maintenance intervention before the pothole becomes critical at which point it could cause damage or injury. Specialist repairs can be scheduled based on the road surface and repair required and roadworks can be better planned. This approach is being trialled in Blackpool (Blackpool Council | Resurfacing works | Project Amber).

The same applies for rail tracks and overhead power lines with examples in the early stages of adoption Pantograph & Overhead Line Monitoring System.

Digital twins

The ability to characterise in detail the hardware and operational dynamics, enables models to be built which are called  digital twins. Simple and complex structures can be characterised. In the pothole example, once the road and surface has been characterised the addition of traffic (type and density), environmental conditions (weather) can then be input to predict the generation and growth of new potholes. This gives the operator more insight in to how to cost effectively maintain assets.

Each mode of transport (roads, airports, maritime ports and rail) are starting to use digital twins to model the infrastructure and the operations they provide for passenger and freight movement. Logistics to manufacturing also use digital twins. With the emphasis on efficiency and safety, having a deeper understanding of how everything works provides the basis for improvement.  

Digital twins and the opportunity to model scenarios, reduces time and expense within the design and development process. They are a focus for connected and autonomous mobility to establish the safe operation of vehicles within the infrastructure which assists in the definition of their ODD (Operational Design Domain), the terrain and environment they can safely operate.

Wider benefits

Inspection and monitoring can also be used to enhance operations to assist in efficient and safe practice as well as maintenance. Freight containers can be considered as temporary infra structure either singly or collectively when stacked. These create hazards on the road, rail or in ports and warehouses which need to be carefully managed and controlled. The state and robustness of these containers is also important to ensure safety. The tracking of containers is also important to maximise throughput at busy terminal and cargo interchanges.

Monitoring infrastructure can also provide data to protect staff and passengers. The location of people, whether PPE is being applied, if there is people crowding and assessment of the comfort and safety of staff and passengers is all possible. The requirement to provide safer and more comfortable environment for passengers is an enabler for a greater uptake of public transport. Therefore, using combining the purpose to monitoring people and structures is a significant opportunity. 

Monitoring and scanning roads will help to inform councils of actual roadworks start and finish times vs the scheduled road works. Highways teams are not aware of the operational reality with hundreds of local roadworks taking place at any given time in a county or city. 

1. Buildings, tunnels, viaducts, aquaducts 

• Structure thermal performance & sustainability.
• Structural fatigue, movement, cracks.
• Operation of ventilation, air flow and presence of emissions.
   

2. Roads, footpaths, runways, rail tracks, overhead power lines

• Surface condition, imperfections and presence of dirt, ice, snow, water.
• Visibility of surface line markings, lighting, signs.
• Robustness of safety structures such as kerbs, railings, bollards.
• Operation of signals to control vehicle movements.
• Condition of tracks, overhead power lines, gantries, crossings.
• Vehicle/ship/aircraft location and stationary objects
• Trespass and vegetation.
• Condition of comms equipment.

3. Emergency services

• Extinguisher devices: water, extinguishers, power supply …. location and status.
• Buildings, storage, response equipment.

4. People

• People counting and location of crowds
• Safety equipment used for PPE, proximity to hazards etc

The ownership and models of operation of airports and maritime ports differs with typical groups for each described below:

Ownership of maritime ports:

Large commercial coastal ports in the UK have a mixture of ownership: 

• Associated British Ports (ABP): UK's largest port operator, managing 21 ports across England, Scotland and Wales including Immingham and Southampton.
• Forth Ports: operates several ports in Scotland, such as Leith, Grangemouth and Dundee.
• Hutchison Port Holdings (HPH): operates the Port of Felixstowe, UK's largest container port.
• Peel Group: owns the Port of Liverpool, managed by the Mersey Docks and Harbour Company.
• Independent Trust Ports: managed by boards of trustees and reinvest profits into the port rather than distributing them to shareholders e.g. Aberdeen, Belfast, Blyth, Dover, London, and Milford Have.

Ownership of airports:

The largest airports are mainly commercially owned, although airports such as Birmingham and Teesside international have significant local government funding.

• Heathrow: Owned by Heathrow Airport Holdings Limited, which is controlled by FGP Topco Limited, a consortium led by Ferrovial SA of Spain.
• Gatwick: Majority-owned by VINCI Airports, a French company, with the remainder owned by Global Infrastructure Partners.
• Manchester: Owned by Manchester Airports Group (MAG), which also operates London Stansted and East Midlands airports. MAG is partially owned by local authorities.
• Glasgow, Aberdeen, and Southampton Airports: Owned by AGS Airports Limited, a joint venture between Ferrovial and AGS Airports International Sarl.

New sensing technologies:

• Structural integrity testing with combined techniques offering better outcomes is outlined in this paper… Sensing Techniques for Structural Health Monitoring: A State-of-the-Art Review on Performance Criteria and New-Generation Technologies
• DAS (distributed Acoustic Sensing) outline principles is covered in this article. Combining photonic neural networks with distributed acoustic sensing for infrastructure monitoring
  Statutory Regulations for roads:
• Design Manual for Roads and Bridges (DMRB): Provides guidelines and standards for the inspection and maintenance of highway structures
• The Road Tunnel Safety Regulations 2007: Sets out the minimum safety requirements for tunnels in the Trans-European Road Network
• Highways Act 1980: Imposes a duty on highway authorities to maintain highways, including bridges and associated structures.
  
  Statutory Regulations for rail:
• Railways and other guided transport systems (Safety) regulations 2006 (ROGS) which covers safety management systems and risk assessment requirements
• Health and Safety at work act 1974 provides an overarching framework for workplace safety
• Rail vehicle accessibility Regulations 2010 ensures accessibility for passengers with reduced mobility
• Network rail standards which includes technical specifications  for infrastructure design, construction and maintenance Network Rail Standards Catalogue - March 2020
• Railways Group standards managed by Rail Safety and Standards Board (RSSB) ensuring safety across the rail network.
  
  Other references:
   
• The reasons infrastructure construction projects are inefficient and costly NIC-Costs-Report-Final-Oct-2024.pdf
•  Climate change has the potential to disrupt transport operations through flooding, subsidence, temperature and extreme weather Climate change risk assessment: transport sector - GOV.UK and the UK Climate risk briefing CCRA3-Briefing-Transport.pdf
• Digitizing infrastructure: Technologies and models to foster transformation
• Road scanning - The Department for Transport (DfT) specifies the use of SCANNER (Surface Condition Assessment for the National Network of Roads) survey vehicles for road condition monitoring. These vehicles are equipped with advanced technologies (lasers and cameras) to measure road surfaces to detect defects and texture. SCANNER technology has been a standard for local roads, while TRACS (TRAffic-speed Condition Surveys) is used for trunk roads.