ProPG stages for a housing scheme beside a railway
Railway sites produce high maximum levels between long quiet periods, so the ProPG assessment turns on events rather than averages and on layout rather than glazing.
A housing scheme beside a surface railway lives or dies on the night-time maximum levels, not the average. ProPG railway noise work starts with an initial site noise risk assessment, and a site within 50 m of a busy freight route will almost always come out as high risk. That classification does not refuse the scheme. It fixes how much evidence you need and how early the layout has to respond.
ProPG: Planning and Noise, published in 2017 by the Association of Noise Consultants, the Institute of Acoustics and the Chartered Institute of Environmental Health, is referenced in validation lists across England. It is guidance rather than policy, and officers treat it as the method by which national noise policy is applied.
The initial site noise risk assessment
Stage 1 places the site into one of four bands: negligible, low, medium or high risk. The input is a survey of the existing noise climate, expressed as LAeq,16hr for the day and LAeq,8hr for the night, with the LAFmax distribution alongside.
Railway sites behave differently from road sites here. A road produces a fairly steady LAeq. A railway produces long quiet periods punctuated by events, so the LAeq can look moderate while the maximum levels are high. A site next to a four-track main line with overnight freight can sit in the medium band on LAeq and the high band on LAFmax.
Survey design matters more than usual as a result. Capture at least one full week including a weekend, log LAFmax at a short time resolution rather than in fifteen minute blocks, and record enough audio to identify the events. Horn use at a level crossing, wheel squeal on a curve and rail joints all produce distinctive signatures that change what mitigation will work.
Ask Network Rail early about planned changes to the line. Timetable changes, electrification and freight path allocations all alter the baseline, and an assessment based on today's service can be challenged.
What a high risk classification means for the layout
High risk triggers the full Stage 2 assessment and, in ProPG terms, means the scheme should only be supported where the acoustic design has demonstrably shaped the proposal.
That is a design instruction, not a reporting one. By the time a masterplan is fixed, the least costly mitigation options have gone. The moves that work are all spatial:
- Put the non-residential uses on the exposed edge. A car park, an energy centre, a gym or a commercial unit between the track and the homes does more than any glazing specification.
- Run a perimeter block with its back to the railway and a quiet courtyard behind, so every dwelling has at least one quiet facade.
- Avoid single-aspect units facing the track. This is the single most common cause of an unacceptable outcome.
- Keep bedrooms on the quiet side wherever the plan allows, accepting that living rooms tolerate a higher level.
- Set external amenity space away from the boundary, or provide it at podium level behind a building rather than at ground level beside the track.
Barriers help less against railway noise than clients expect, because the source often sits above ground level and includes aerodynamic and structure-borne components. Our note on what an acoustic barrier actually achieves sets out the geometry.
Element one: good acoustic design
The first of the four elements in Stage 2 is the acoustic design process itself, and it is assessed on evidence that the process happened.
What that looks like in a submission: a record of the options considered, the layout iterations tested, the acoustician's input at each design stage, and the reasons for the choices made. A report that arrives at the end with a glazing schedule and nothing else fails this element even if the numbers work.
Include the rejected options. Showing that a single-aspect block along the boundary was tested and abandoned is stronger evidence of a design process than any amount of description.
Element two: internal noise level guidelines
Element 2 uses the internal levels in BS 8233:2014: 35 dB LAeq,16hr in living rooms during the day and 30 dB LAeq,8hr in bedrooms at night, with a separate check on individual events.
The event check is the railway-specific one. BS 8233 notes that regular individual noise events can disturb sleep and that a limit expressed as LAFmax is appropriate, with 45 dB in bedrooms at night the figure most commonly applied and a limit on how often it may be exceeded. Agree both the level and the permitted number of exceedances with the environmental health officer before modelling, because the two together determine the glazing and ventilation specification.
Then there is the ventilation trap. Internal levels achieved with windows closed require an alternative means of ventilation under Approved Document F, and the same closed-window case has to work for overheating under Approved Document O. Specify mechanical ventilation with a sound-attenuated path, and model the overheating case with the windows shut, because a scheme that passes acoustics by closing the windows and then fails Part O has not passed anything.
Set out the results room by room in a table the officer can check, as covered in our note on the BS 8233 sections of a residential noise assessment.
Element three: external amenity areas
Element 3 covers gardens, balconies, terraces and communal amenity space. BS 8233 gives a desirable upper limit of 50 dB LAeq,T for external amenity areas, with a higher figure tolerated in some circumstances where the development is otherwise acceptable and this is explained.
Railway sites rarely achieve 50 dB at every amenity space, and ProPG does not require them to. What it requires is that the shortfall is identified, quantified and justified, with the balance of amenity across the scheme set out.
Practical responses: a screened balcony with an absorptive soffit, a winter garden that can be opened or closed, communal space in the sheltered part of the site, and a play area located on the quiet side. Where a balcony faces the track, state its assessed level rather than omitting it from the report, because omission is what triggers the further information request.
Element four: other relevant issues
Element 4 sweeps up everything the first three do not cover, and on railway sites it carries real weight.
Local policy comes first. Many authorities have their own noise standards in an adopted plan or supplementary planning document, and where they are stricter than BS 8233 they govern. The national framework applies through the Noise Policy Statement for England and its concepts of the lowest observed adverse effect level and the significant observed adverse effect level, and the assessment should state where the site sits against both.
Vibration and ground-borne noise belong here too. Close to a railway, particularly where there is a cutting, a tunnel or jointed track, vibration can be perceptible inside dwellings and is assessed separately against BS 6472-1. It is a distinct discipline requiring a specialist, and it is not part of a noise assessment. PlanScope does not produce a vibration assessment, so budget for one separately where the risk is real.
Agent of change also sits in Element 4 where the railway operator's activity might change, and the balance of responsibility between an incoming developer and an established operator is worth setting out explicitly.
The acoustic design statement the council expects
The deliverable from ProPG is an acoustic design statement bringing all four elements together. Structure it in the order the officer will read it:
| Section | Content |
|---|---|
| Stage 1 | Survey method, dates, positions, results, risk classification |
| Element 1 | Design process, options tested, decisions and reasons |
| Element 2 | Internal levels by room type, with the ventilation and overheating position |
| Element 3 | External amenity levels by space, with any shortfall justified |
| Element 4 | Local policy, national policy position, vibration, agent of change |
| Recommendation | The overall ProPG outcome and the conditions proposed |
Propose your own conditions. An acoustician who drafts the glazing and ventilation condition, naming the specification document and its revision, usually gets that wording adopted, and it is better than the environmental health officer's standard clause.
Councils normally expect a noise impact assessment of this kind to be prepared by a suitably qualified acoustician, and professional review before submission is strongly advised. The two-stage structure is set out more fully in our note on the ProPG two-stage approach.
Enter your postcode on PlanScope to see which reports a site beside a railway is likely to need.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What are the four elements of a ProPG Stage 2 assessment?
Element 1 is the good acoustic design process. Element 2 covers internal noise level guidelines. Element 3 covers external amenity areas. Element 4 covers other relevant issues, including local policy, the national policy position, vibration and agent of change. The assessment then reaches an overall recommendation on the proposal.
Why do railway sites classify differently from road sites?
Road traffic produces a fairly steady equivalent continuous level, while a railway produces long quiet periods punctuated by events. A site can therefore sit in the medium risk band on LAeq and the high band on maximum levels. Log LAFmax at a short time resolution and record audio so the events can be identified.
What internal noise levels should a scheme achieve?
BS 8233:2014 gives 35 dB LAeq,16hr in living rooms during the day and 30 dB LAeq,8hr in bedrooms at night. A separate check applies to individual events, with 45 dB LAFmax in bedrooms the figure most commonly used along with a limit on how often it may be exceeded. Agree both with environmental health first.
What level applies to gardens and balconies?
BS 8233 gives a desirable upper limit of 50 dB LAeq,T for external amenity areas, with a higher figure tolerated where the development is otherwise acceptable and the position is explained. Railway sites rarely meet 50 dB everywhere, so identify the shortfall, quantify it and justify it rather than omitting the space.
Does a noise assessment cover vibration from the railway?
No. Ground-borne vibration and ground-borne noise are assessed separately, against BS 6472-1, by a specialist in that field. Sites near cuttings, tunnels or jointed track are the ones most at risk. PlanScope does not produce a vibration assessment, so budget for it separately where the risk is real.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.