ConnectedCities identify groups of stations around hub towns. LMAs identify the next level up: groups of ConnectedCities, towns and rail corridors that:
form a recognisable functional area;
can be operated as a coherent local rail network;
contain sufficient population and destinations to support frequent services;
have meaningful potential for modal shift and station-centred growth; and
can be governed and planned as one programme.
Start with stations, towns, passenger flows and rail journey times, and identify where the strongest relationships occur.
Test whether the resulting area can support a coherent metro service and whether its boundaries make operational, spatial and governance sense. Neither approach is sufficient alone: present flows may reproduce the limitations of poor services, while an attractive conceptual geography may be impossible to operate.
Stage 1: Map the candidate rail network
Map existing passenger railways, stations, service frequencies, settlements above 10,000, smaller strategically important rail-served settlements, major destinations, planned housing and employment, proposed stations, freight and intercity routes, and connecting bus, light-rail and rapid-transit networks.
Stage 2: Identify LMA anchors
Identify towns, cities and major destinations around which local rail relationships are organised. Potential anchors should be assessed using population, jobs and services, rail connectivity, daily travel attraction, interchange importance and planned growth.
Stage 3: Construct functional rail catchments
For each anchor, map stations within 30 minutes as the core catchment, 45 minutes as the normal outer catchment, and up to 60 minutes where needed to complete a coherent corridor or include a strong secondary anchor. Use generalised rail time, not scheduled journey time alone.
Stage 4: Measure functional relationships
Score each station against competing anchors using rail accessibility, observed movement, service-pattern compatibility, access to opportunities and growth or development relationships.
Stage 5: Group stations into candidate LMAs
Allocate each station initially to the anchor with the highest affiliation score. Permit primary, secondary and shared affiliations so boundary and interchange stations are recognised.
Stage 6: Test each candidate as a complete network
Require contiguity, functional coherence, metro service feasibility, sufficient scale and intensity, and meaningful place and development value.
Stage 7: Calculate and classify an overall LMA score
Score candidates for functional coherence, rail feasibility, population and settlement scale, development potential, multimodal integration and governance alignment.
Stage 8: Consult and refine
Ask communities, transport and planning authorities, GBR and operators to review the analytical result. Adjust paper boundaries where local knowledge or operating requirements justify doing so.
Screening thresholds and anchor formula
A candidate LMA should normally contain at least one principal centre above 50,000, at least three rail-served towns above 20,000, or a combined existing and committed-growth population above approximately 150,000. These are screening values rather than immutable rules.
Smaller settlements may still be included where they are important interchanges, rural railheads, growth locations, corridor-filling stations, branch termini or operating turnback points.
Anchor Score Aᵢ = 0.30Pᵢ + 0.20Jᵢ + 0.15Rᵢ + 0.15Dᵢ + 0.10Iᵢ + 0.10Gᵢ
P is population; J is jobs, education and service destinations; R is rail connectivity; D is daily travel attraction; I is interchange importance; and G is planned growth. Each variable is normalised from 0 to 100 within the study region.
An anchor would normally have a population above 30,000, a station or central station group, at least two railway directions or a particularly important corridor function, major daily destinations, and potential to support a half-hourly or better local rail frequency.
GRTᵢⱼ = Tᵢⱼ + 0.5Hᵢⱼ + Xᵢⱼ + Rᵢⱼ
T is scheduled journey time; H is service headway, capped to avoid excessive distortion; X is an interchange penalty; and R is a reliability penalty. A nominal 25-minute journey every two hours is therefore not treated as equivalent to a 25-minute journey four times per hour.
Calculate both current GRT and metroised GRT based on a regular half-hourly or 15-minute service. This distinguishes geographic weakness from shortcomings in the existing timetable.
Station-to-anchor affiliation
Fᵢⱼ = 0.30Tᵢⱼ + 0.25Mᵢⱼ + 0.15Sᵢⱼ + 0.15Oᵢⱼ + 0.15Gᵢⱼ
T is rail-time accessibility; M is observed movement; S is service-pattern compatibility; O is access to opportunities; and G is growth and development relationship. Each component is scored from 0 to 100.
Rail-time accessibility, 30%
Tᵢⱼ = 100e⁻⁰·⁰³⁵ᴳᴿᵀⁱʲ
This gives greater weight to stations within approximately 30 to 45 generalised minutes while avoiding an arbitrary cliff edge.
Observed movement, 25%
Use rail origin-destination data, appropriately anonymised mobile movement data, public-transport flows, commuting, education and healthcare trips, retail and leisure movement, and road origin-destination data. Use flows in both directions and avoid relying only on commuting.
Service-pattern compatibility, 15%
Assess whether the station can join the same repeating timetable without excessive path conflicts, an unreasonably long service, irregular intervals, operational incompatibility or disproportionate harm to intercity and freight services.
Opportunity accessibility, 15%
Measure access within 30, 45 and 60 minutes to jobs, education, hospitals, town centres, retail, visitor destinations and interchange hubs
Growth relationship, 15%
Measure planned housing and employment, developable land, regeneration areas, new-station opportunities and potential for sustainable settlement expansion. Use probabilistic station catchments where possible rather than assigning every household to the nearest station.
Primary affiliation: Fᵢⱼ ≥ 60 and at least 10 points above the next-highest score
Shared station: |Fᵢⱼ - Fᵢₖ| < 10
Where no score reaches 60, test the station as a corridor-filling station, outer railhead, branch terminus, strategic interchange, development opportunity or part of an adjoining LMA. Do not automatically exclude it.
Five pass/fail network tests
Contiguity
Stations must form a continuous rail network. Disconnected corridors should be included only where they connect strongly through a principal interchange and can be understood as one passenger network.
Aim for at least 60% two-way containment of relevant short and medium-distance trips. This is below the traditional 75% Travel to Work Area criterion because an LMA is an open, all-purpose transport network and is intended partly to enable future modal shift.
Metro service feasibility
Demonstrate a credible service structure providing a half-hourly base service at most stations, a 15-minute combined frequency on the core or principal corridors, regular intervals, dependable interchange and acceptable recovery margins.
Sufficient scale and intensity
Normally satisfy at least two of: population above 150,000; existing plus committed growth above 200,000; six or more stations; three substantial rail-served settlements; two major daily destinations; four trains per hour on the core; or a substantial modal-shift market.
Place and development value
Show a meaningful portfolio of station areas offering housing, regeneration, employment, brownfield reuse, new stations, active-travel access or interchange investment. Use 1 km as an initial strategic station catchment, refined by the real walking and cycling network.
LMA Score = 0.25FC + 0.25RF + 0.20PS + 0.15DP + 0.10MI + 0.05GA
FC is functional coherence; RF is rail feasibility; PS is population and settlement scale; DP is development potential; MI is multimodal integration; and GA is governance alignment.
Score: 75-100 - Priority LMA - Strong functional and operational case
Score 60-74 - Potential LMA - Promising, but needs timetable, infrastructure, boundary or development work
Score 45-59 - Emerging LMA - Longer-term proposition dependent on enhancement or growth
Score below 45 - Corridor or feeder area - Better treated within another LMA or as regional rail
Essential floor conditions: a high composite score cannot compensate for Rail Feasibility below 50, Functional Coherence below 50, or a non-contiguous network.
Follow functional rail relationships first
Overlay administrative boundaries only after the functional geography has been identified. LMAs may cross local authority, mayoral, GBR, Network Rail, county or national boundaries.
Define nodes and links, not only a perimeter
Record included lines, core, intermediate, outer and boundary stations, associated station catchments, settlements and strategic development areas.
Distinguish core from outer area
Define a metro core with at least four trains per hour in combination, metro corridors normally with at least two trains per hour, outer branches with integrated one- or two-train-per-hour services, and interface stations.
Neighbouring LMAs may share stations, common sections, services, fleets, control functions and information systems, provided responsibilities are explicit.
Consider division where end-to-end local journeys exceed about 90 minutes, corridors have little relationship, several weakly connected anchors exist, one service pattern cannot represent the network, or local accountability becomes remote.
Resolving overlaps between anchor areas
Affinityᵢⱼ = (Pⱼ⁰·³⁰ × Jⱼ⁰·²⁰ × Sᵢⱼ⁰·²⁰ × Mᵢⱼ⁰·³⁰) ÷ GRTᵢⱼ¹·²⁵
P is anchor population; J is jobs and destination strength; S is service-pattern compatibility; M is observed movement; and GRT is generalised rail time. The exponents are proposed calibration parameters, preventing population alone from dominating and giving substantial weight to time and actual relationships.
Allocate primarily where one anchor's affinity exceeds the next highest by a factor greater than 1.25.
Designate a shared or interface station where the ratio lies between 0.80 and 1.25.
Where neither affinity is strong, test for a smaller cluster or outer regional role.
