The findings in brief
Ireland's rail network is roughly 40% of its ~1920s peak of about 5,600 route-km; the all-island network today is near 2,300 km, which the 2024 All-Island Strategic Rail Review would grow to almost 3,000 km. Two ideas run through everything below. First: corridor survival, not demand, is the biggest driver of reinstatement cost — land reassembly is where budgets explode. Second: a railway's worth depends entirely on how wide you draw the accounting boundary, and Ireland's standard appraisal draws it narrowly, in a way that is structurally biased against rail.
Everything here distinguishes measured figures (route-km, ownership, published costs) from modelled ones (benefit-cost ratios, forecasts) and contested ones (advocacy figures). The ~5,600 km peak is approximate.
Part 1 — What survives, ranked by reinstatement difficulty
Closed corridor falls into three tiers. The tier sets the capital cost far more than route length does, because land reassembly — not track — is the expensive variable.
TIER A State-owned & mothballed
Never sold, still in CIÉ / Iarnród Éireann ownership — the home of every live project. Lowest cost: no land to buy.
Western Rail Corridor (~240 km, intact), Limerick–Foynes (42 km, under construction), Navan (~34 km, corridor reused). WRC implied roughly €5m/km.
TIER B Converted to greenway
Corridor physically preserved; licensed (not sold) to councils to keep the rail option open. Reversible in principle, frictional in practice.
Waterford (46 km), Great Western (42 km), Old Rail Trail (42 km), Limerick (~40 km), Boyne Valley to Lakelands (30 km) — ~200 km preserved in five alone.
TIER C Sold, built over, encroached
Highest cost: needs reacquisition / CPO. Cost and planning risk rise sharply.
Harcourt St (part-reused as Luas), the ~210 km Derry–Mullingar gap, and the Sligo case — an "alongside" route needed private land for over 70% of the route at +22% cost.
Part 2 — Why value is built in layers
The four layers are cumulative: each adds one category of benefit to the numerator while the discounted whole-life cost stays fixed. Ireland's Transport Appraisal Framework (consistent with the Public Spending Code) uses a real discount rate of 4%, an appraisal horizon around 30 years, a value of working time near €26/hour, CBA above €20m, and BCR ≥ 1 as the feasibility threshold. Crucially, standard Irish CBA largely omits land-use change and land-value uplift — Metrolink's own uplift was excluded from its headline BCR — which is part of why Ireland has among the lowest electrified-rail shares in the EU.
| Layer | Adds to benefits | Evidence quality | Verdict it can justify |
|---|---|---|---|
| 1 · Farebox | Fare revenue vs cost | Hard / measured | Commercial — almost never met |
| 2 · + Direct transport | Journey time, decongestion, reliability, safety | Solid; standard CBA boundary | Standard case (where the All-Island Review lands) |
| 3 · + Wider economic | Land-value uplift, housing enablement, agglomeration | Contingent; often omitted | Conditional — needs value capture + density |
| 4 · + Environmental & social | Carbon, air quality, access, equity, option value | Soft; price/discount-sensitive | Strategic / decarbonisation — fragile |
Part 3 — The build-decision model
The rule: build a line at the lowest layer where its cumulative BCR reaches 1 — and read the layer it needs as a measure of how robust, and how conditional, the case is. The deeper you must go, the more the case rests on soft numbers and on complementary policy actually being delivered.
Three gates sharpen the rule: a corridor-tier gate (a Tier A/B line clears a lower layer than an identical Tier C line, because its cost is smaller), a density threshold (Layer 3 housing benefits need real, serviced development capacity), and a capture condition (land-value uplift only counts if some is actually captured to the public purse).
Build explorer — set the variables, read the verdict
Toggle which benefit layers you count, filter by corridor tier, and switch the two conditions on or off. Each line's verdict recomputes live. The layers are cumulative — turning off a lower layer removes everything above it. Each line's "closes at" layer is an editable assumption drawn from the review, not a formal appraisal: change it and watch the verdict move.
Benefit layers (cumulative)
Layer 3 conditions
Both required for any line that relies on Layer 3.
Corridor tiers shown
A = intact · B = greenway · C = lost / new-build.
| Line | Tier | Closes at | Verdict | Why |
|---|
Verdicts are the logic of the model applied to each line, not a costed appraisal. "Closes at" is adjustable because the honest answer depends on demand modelling Ireland does not publish per corridor.
Decision map — verdicts on the network
The same variables as the explorer, drawn on the map. Toggle the benefit layers, corridor tiers and Layer-3 conditions, and each candidate line changes colour to its live verdict. The grey network is what operates today; the coloured lines are the reinstatement candidates. These controls are linked to the explorer above — changing either updates both.
Benefit layers (cumulative)
Layer 3 conditions
Corridor tiers shown
Candidate routes are indicative — straight connectors between real stations, not surveyed alignments. The "border gap" and DART+ lines are schematic placements of the Review's proposals. Verdicts are the model's logic applied per line, not a costed appraisal.
The network, then / now / proposed
A schematic of the principal lines — which places connect, not exact routes. Switch between the network at its ~1920s peak, the network operating today, and the network the All-Island Strategic Rail Review would build.
Schematic: principal lines only, positions approximate; major lines shown, not every branch. "Historic" is the network near its 1920s peak. "Proposed" follows the All-Island Strategic Rail Review — the Western Rail Corridor, Navan and Foynes are shown; the Review also proposes further North-West lines, electrification and higher speeds not all mapped here.
How the model assesses each layer
Short version: the model does not calculate benefit-cost ratios — it applies a single rule and makes one transparent assumption per line. The rule is that a line is justified at the lowest layer where its benefits would cover its cost (a BCR of 1). The layers themselves mirror the real categories an appraisal is allowed to count.
Where the layers and parameters come from
The four layers and the numbers behind them are Ireland's actual appraisal rules, not invented. The Transport Appraisal Framework (consistent with the Public Spending Code) sets a 4% real discount rate, a roughly 30-year horizon, a value of working time near €26/hour, the BCR ≥ 1 feasibility threshold, and a rising shadow price of carbon for Layer 4 — all referenced below. What that standard framework leaves out — land-value uplift and housing — is exactly what Layer 3 adds, following the cited critique of Irish cost-benefit practice.
The one assumption per line: its "closes at" layer
The only line-specific input is the layer at which each corridor's case first closes. This is a reasoned judgement from the published evidence, not a computed figure, because Ireland does not publish per-corridor BCRs across all four layers. Each judgement traces to a source:
- WRC Athenry–Claremorris → Layer 3. The 2020 EY appraisal found it poor value on a standard (Layer 2) basis and favoured "do nothing"; it turns positive only once wider / regional benefits are counted.
- Navan and DART+ extensions → Layer 2. Busy commuter corridors into Dublin that stand up as standard transport cases, with the Government's housing plan treating them as housing enablers — their Layer 3 upside.
- Thin western / border lines (WRC–Sligo, West Cork, the border gap) → Layer 4. Very low year-round demand, so the case rests mainly on carbon, access and regional-rebalancing grounds.
Because these are judgements rather than appraisals, every one is editable in the explorer and the decision map — change a line's "closes at" layer and its verdict moves. Read the outputs as the logic of the framework applied consistently, not as a costed appraisal. Where a figure is genuinely contested — the Western Rail Corridor is the clearest case, with two credentialled studies reaching opposite answers — the tool exposes the assumption rather than burying it inside a single number.
References
Sources opened for this work. Figures from general knowledge (the ~5,600 km peak; some ownership labels) are marked approximate above.
- All-Island Strategic Rail Review — final report, Dept of Transport / gov.ie, 2024.
- All-Island Review summary, Irish Construction News, 2024.
- Western Rail Corridor — future and EY appraisal, TheJournal, 2021.
- WRC 100% State ownership; Sligo corridor, IrishCycle, 2025.
- Sligo greenway licence preserves reopening, RTÉ, 2026.
- Sligo greenway shelved — 70% private land, +22% cost, RTÉ, 2025.
- Limerick–Foynes line (mothballed, reopening), Wikipedia.
- Waterford Greenway (CIÉ owner), Wikipedia.
- Great Western Greenway, Wikipedia.
- Old Rail Trail (Athlone–Mullingar), Wikipedia.
- Boyne Valley to Lakelands Greenway, Wikipedia.
- Harcourt Street railway line, Wikipedia.
- Housing plan: rail as a housing enabler, Iarnród Éireann, 2026.
- DART+ South West land acquisition / Adamstown, Iarnród Éireann.
- TOD without going bust (value capture), Progress Ireland, 2026.
- Why CBA excludes land use; Metrolink uplift, Progress Ireland, 2026.
- Land readjustment, Progress Ireland, 2025.
- TOD critical; NESC 2.5 km corridor density, Irish Times / NESC, 2019.
- Transport Appraisal Framework, Module 7 (4% discount rate), gov.ie.
- Transport Appraisal Framework, Module 8 (value of time ≈€26/hr), gov.ie.
- Common Appraisal Framework for Transport, 2016 (BCR>1; €20m), gov.ie.
- Cost-Benefit Analysis, Environment and Climate Change (carbon discount rate), NESC.