Straight answers to the questions we’re asked most — about our surveys, monitoring and testing services, and what it’s like to work with us. Can’t find what you need? Contact an expert and we’ll answer within one working day.
Jump to: Working with Infrastruct North · Land & topographic surveys · Utility mapping & GPR surveys · Railway gauging surveys · Railway track surveys · Railway track monitoring · Structural monitoring · Structural inspection, testing & concrete scanning · Laser scanning & 3D modelling · Drone surveys · Vibration & noise monitoring · Geotechnical investigation · Ecology · Site engineering & civil engineering
Working with Infrastruct North
What does Infrastruct North do?
We’re a multi-discipline construction specialist providing surveying, monitoring, engineering and testing services to the rail, civil engineering and telecoms sectors — from topographic and utility surveys through gauging, laser scanning and structural monitoring to site engineering and civils delivery.
Where do you work?
We’re headquartered in Liverpool and work UK-wide for clients including principal contractors and train operators. Through Infrastruct North WLL, our international arm, we also deliver projects overseas — most recently a runway GPR survey at Mukhaizna Aerodrome in Oman.
What accreditations do you hold?
We are RISQS-accredited for work on the rail network, certified to ISO 9001 (quality), ISO 14001 (environmental) and ISO 45001 (health and safety), Constructionline registered and a CIRAS member. Certificates are available on our Downloads page.
Can you work on live railway infrastructure?
Yes — much of our work is on or beside the operational railway. We plan and deliver work under possessions and line blocks, working closely with rail operators and access planners, and our surveys are carried out to the relevant Network Rail standards.
What do you need from us to provide a quote?
A site location, a brief description of what you’re trying to achieve, any drawings or specifications you have, and any known constraints (access, possessions, deadlines). We’ll come back quickly with a clear scope and price — call 0151 727 3796 or email info@in-l.co.uk.
How much does a survey cost?
It depends on the size and complexity of the site, the accuracy specification, access (including any track access), and the deliverables you need — which is why we don’t publish a price list. Quotes are free, fast and itemised, so you can see exactly what you’re paying for.
How quickly can you start?
For most surveys we can mobilise within a week of instruction. Where booked track access is needed — possessions or line blocks — the programme is planned around the available access, and we’ll give you realistic dates in your quote.
Our project is small — will you still take it on?
Yes. We deliver everything from single-visit surveys to multi-year monitoring programmes, and small jobs get the same standards, reporting and care as major schemes.
Full details: About Infrastruct North
Land & topographic surveys
What is a topographic survey?
A topographic (or land) survey maps the natural and man-made features of a site along with ground levels and contours — the base information designers and engineers need to plan and build accurately.
When do I need one?
Whenever you’re designing a new structure, extending an existing one or planning site improvements: an up-to-date survey means you’re working from accurate information and helps avoid costly errors later.
How accurate are your surveys?
Accuracy is matched to your project’s specification. All surveys are carried out with high-precision equipment to RICS and, where applicable, Network Rail and other sector standards, with rigorous quality checks before anything is issued.
Can you show underground utilities on the same survey?
Yes — we regularly combine topographic and utility mapping data into one deliverable giving a complete surface and sub-surface picture of your site.
What will I receive, and how long does it take?
Deliverables come in the digital formats that suit your team — CAD, PDF or GIS. Fieldwork ranges from a few hours to several weeks depending on the site, and we agree a clear schedule with you at the start.
Full details: Land Surveying
Utility mapping & GPR surveys
What is a utility mapping survey?
It locates and maps underground services — pipes, cables and ducts — recording their position and depth before groundworks begin, so you can design and excavate safely.
Why do I need one?
Striking a buried service is dangerous and expensive. A utility survey de-risks excavation, supports safe digging practices and gives designers reliable information — utility record drawings alone are often incomplete or out of date.
What are the PAS 128 quality levels, and which do I need?
PAS 128 grades utility data from QL-D (desktop records search) and QL-C (site reconnaissance) up to QL-B (detection on site using GPR and electromagnetic location) and QL-A (verification by trial hole). Most construction projects need QL-B, with QL-A verification where excavation or piling is close to critical services — we’ll advise the right level for your risk.
Can you identify the type and material of a utility?
In many cases, yes. Our equipment can often distinguish metallic from non-metallic services and indicate the likely function — water, gas, electric or telecoms.
Do you need to dig?
Most of the work is entirely non-intrusive. Where physical confirmation is needed — always the case for PAS 128 QL-A — we coordinate trial holes or vacuum excavation to verify locations and depths.
Can it be combined with a topographic survey?
Yes, and it usually should be: one visit, one control network, and a single drawing showing surface and sub-surface features together.
Full details: Utility Mapping Surveys
Railway gauging surveys
What is a railway gauging survey?
It measures and records the relationship between the track and nearby structures — bridges, platforms, tunnels, signals — to confirm trains can pass safely without obstruction.
Why are gauging surveys important?
Because clearances are safety-critical. Gauging confirms structures and track alignment comply with clearance standards, prevents contact between trains and infrastructure, and underpins design and maintenance decisions.
Can you assess clearance for new or modified rolling stock?
Yes. Our gauging data supports vehicle path and kinematic envelope analysis, confirming whether proposed rolling stock or infrastructure changes will run safely within the available space.
What methods do you use?
A combination of manual track, platform and structure gauges and laser sweep instruments, chosen to suit the site conditions and the accuracy your project requires — all to the relevant Network Rail standards.
Do you need track access?
Yes. We work closely with rail operators and access planners to arrange possessions or line blocks safely and efficiently, and we build access constraints into the programme from the start.
Full details: Railway Gauging Surveys
Railway track surveys
What is a railway track survey?
It captures the precise position, alignment, elevation, curvature, cant and condition of the track — essential data for design, maintenance, verification and safety.
How accurate are your track surveys?
We work to tight tolerances set by the relevant Network Rail standard or your project specification, using high-precision instruments and strict quality control.
Can the survey pick up track wear and defects?
Yes — rail wear assessment, profile checks and condition reporting can be included in the survey package where required.
Can you survey long sections, and combine the results with other surveys?
We survey extended sections and full corridors, and track data is often combined with topographic, drainage, utility and ground investigation information into one comprehensive deliverable.
Full details: Railway Track Surveys
Railway track monitoring
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What is railway track monitoring?
It’s the repeated, precise measurement of track position and geometry over time, to detect movement — typically where construction, excavation, piling or tunnelling is happening on or near the operational railway.
When is track monitoring required?
Usually when works adjacent to the railway could affect track support or alignment — asset owners and Network Rail commonly require a monitoring regime, with agreed trigger levels, before such works can start.
Do you monitor manually or automatically?
Both. Manual monitoring uses precise instruments reading prism arrays at agreed intervals; automated systems take continuous readings and report remotely. We’ll recommend the approach that fits your risk level, access and budget.
What happens if movement is detected?
Readings are checked against pre-agreed alert thresholds. If a trigger level is breached you’re notified immediately, so works can pause and the response plan can be enacted before safety or asset condition is affected.
Full details: Railway Track Monitoring
Structural monitoring
What is structural monitoring?
Measuring how a structure behaves over time — deflection, strain, tilt, vibration and settlement — so engineers and asset owners understand its real-world performance.
Why is it important?
It detects issues early, validates designs, informs maintenance planning and manages risk with evidence rather than assumption.
How long does monitoring last?
Anywhere from a few days to several years. We agree a duration and reporting schedule to suit the project, and real-time systems with automated alerts are available where you need immediate warning of change.
Will the equipment affect the structure?
No. Installations are minimally invasive and planned so sensors and cabling don’t affect integrity, access or appearance — and stay protected for the life of the programme.
Full details: Structural Monitoring
Structural inspection, testing & concrete scanning
What is structural inspection and testing?
Visual examination combined with non-destructive evaluation and material testing to assess the condition, safety and remaining life of structural elements — and to locate hidden features such as reinforcement and cables.
What’s the difference between GPR and Ferroscan?
Ground-penetrating radar (GPR/pulse radar) transmits radar pulses into the structure and detects objects, voids and layers — including non-metallic features — at depth. Ferroscan is an electromagnetic technique focused on near-surface reinforcement: bar position, cover depth and diameter estimation. We often use both together for a complete picture.
Can you locate rebar, cables and voids before drilling or coring?
Yes — scanning before you cut is exactly what these techniques are for, and we strongly recommend it before any coring, drilling or structural alteration.
Can you test for corrosion and concrete degradation?
Routinely: corrosion assessment, carbonation depth, chloride profiling and concrete strength testing, alongside visual checks for spalling, cracking and delamination.
How intrusive is testing?
Most methods are non-destructive. Where sampling, break-outs or coring are genuinely needed, they’re limited, agreed with you first and made good.
What does the report look like?
A structured PDF or digital report with results, annotated drawings, photographs, observations, risk levels and recommended actions — written to be used, not filed.
Full details: Structural Inspection & Testing
Laser scanning & 3D modelling
What is laser scanning and 3D modelling?
Laser scanning captures the physical environment as a dense point cloud; 3D modelling turns that data into usable digital geometry — meshes, drawings or BIM models that mirror the real world.
How accurate are your scans?
Accuracy is driven by the instrument, control network and conditions; we agree the tolerance your project needs before quoting and register every scan against it, working to RICS and Network Rail standards where they apply.
Can you scan internal and external spaces?
Yes — interiors, exteriors and complex or constrained spaces, using static, mobile or handheld scanners depending on access and geometry.
Can the data tie into my existing design model?
Yes. We align scan data with your CAD, BIM or GIS models for overlay, verification and clash detection.
What formats do you deliver?
Whatever suits your workflow: LAS, E57, OBJ, STL, DWG, Revit/BIM exports, plus annotated drawings and visualisations.
Full details: Laser Scanning & 3D Modelling
Drone surveys
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When is a drone survey the right choice?
For large, complex or hard-to-access assets — viaducts, bridges, roofs, embankments, live infrastructure — where working at height or arranging access would be slow, costly or risky. Drone capture is fast, safe and non-disruptive.
How accurate is drone LiDAR?
Flown with RTK positioning and tied into ground control measured by total station and GNSS, our drone LiDAR produces fully geo-referenced point clouds accurate enough for structural condition assessment — as delivered on the 99 Arches viaduct at Wakefield.
Are your drone operations CAA-compliant?
Yes. Our drone surveys are flown by qualified remote pilots operating in line with Civil Aviation Authority (CAA) regulations, with the required permissions and airspace approvals in place for each flight — including work in rail environments.
What do I receive from a drone survey?
Typically a geo-referenced point cloud (e.g. LAZ), imagery, an accuracy report, and any modelling or drawings you need on top — ready to drop into your design or assessment workflow.
See it in action: Wakefield 99 Arches Viaduct Drone Survey
Vibration & noise monitoring
What is vibration and noise monitoring?
Measuring ground movement and sound levels around construction, demolition or industrial activity to assess and control the impact on people, buildings and the environment.
Is monitoring required by law?
Often, yes — planning conditions and environmental permits frequently set noise and vibration limits, and monitoring provides the evidence of compliance that regulators and local authorities expect.
Can you provide real-time alerts?
Yes. Automated alerts notify you the moment a pre-agreed threshold is exceeded so corrective action can be taken immediately.
Can you monitor several locations at once — and remotely?
Yes on both counts: multiple units can run across a site or corridor simultaneously, with secure online access to the data from anywhere.
How long can monitoring run?
From short-term monitoring of a single activity to permanent installations covering the life of a project.
Full details: Vibration & Noise Monitoring
Geotechnical investigation
What is a geotechnical investigation?
Also called a ground investigation, it establishes the physical properties of the ground beneath your site — the information foundations, earthworks and infrastructure design depend on.
What testing do you carry out?
A range of in-situ and laboratory testing covering soil strength, composition and groundwater behaviour, scoped to what your project actually needs.
Do you provide factual or interpretive reports?
Either — factual reporting of results, or full interpretive reports with analysis and design recommendations.
Can it be combined with other surveys?
Yes — ground investigation pairs naturally with utility mapping and topographic survey for a complete picture of site conditions above and below ground.
Full details: Geotechnical Investigation
Ecology
Which ecology services do you provide?
Surveys, assessments and management work covering habitats, protected species and ecological constraints, plus the mitigation strategies that flow from them.
Why do I need an ecological survey?
Many projects are legally required to have one. Surveys keep you compliant, protect biodiversity, manage risk and — crucially — avoid planning delays.
Do you handle statutory licensing?
Yes. We support species licensing, liaise with statutory bodies and prepare the documentation needed when protected species are present.
Do you deal with invasive species?
We do — assessment of invasive non-native species and advice on control and mitigation plans.
Full details: Ecology Services
Site engineering & civil engineering
What is site engineering (setting out)?
Marking the position of design elements — foundations, structures, utilities — onto the site with precise measurement, so what gets built matches what was designed.
Why does it matter?
Accurate setting out prevents construction errors, reduces rework, keeps the programme moving and protects safety.
What do you need from our design team?
Digital design drawings, control coordinates, levels, grid lines and any tolerances or constraints — we confirm exactly what’s needed at the start.
Do you keep checking during construction?
Yes — continuous checking and verification through the build, with any out-of-tolerance findings recorded clearly and resolved with your team before work continues.
What civil engineering works do you deliver?
Full construction packages for rail and power infrastructure: substation foundations and compound construction; walkways, platforms and access roads; drainage and attenuation systems; lineside works and embankment stabilisation; and station and depot upgrades. Recent examples include the 145-bay car park renewal at Normanton Station and the new safe access walkway at Clapham Depot.
Full details: Site Engineering
Still have a question?
Every project is different — tell us about yours and we’ll give you a straight answer. Contact an expert or call 0151 727 3796.