Flat grade share
- Portland Coastal Marathon 10K
- 39.6% Favoured
Two Tunnels Railway Races 10K vs Portland Coastal Marathon 10K
A data-led head-to-head using sourced race facts and available derived figures under one published methodology.
Data current as ofTwo Tunnels Railway Races 10K or Portland Coastal Marathon 10K — which comes out ahead?
Portland Coastal Marathon 10K has the stronger available profile on flat grade share, course flatness and scenery score.
Route comparison snapshot
Two Tunnels Railway Races 10K
- Mapped route
- Held
- Elevation profile
- Held
- course flatness
- 5.8%
- flat grade share
- 39.0%
- lower ascent
- 244 m
- climbing density
- 24.4 m/km
- net elevation
- 2 m
- maximum grade
- 18.1%
Portland Coastal Marathon 10K
- Mapped route
- Held
- Elevation profile
- Held
- course flatness
- 4.8% Favoured
- flat grade share
- 39.6% Favoured
- lower ascent
- 207 m
- climbing density
- 20.7 m/km
- net elevation
- -0 m
- maximum grade
- 22.0%
| Metric | Two Tunnels Railway Races 10K | Portland Coastal Marathon 10K |
|---|---|---|
| Flat grade share | 39.0% | 39.6% ✓ |
| GAP factor (% slower than flat) | 5.8% | 4.8% ✓ |
| Uphill share | 31.0% | 31.2% |
| Steep-up share | 16.4% | 11.5% |
| Downhill share | 30.0% | 29.2% |
| Total ascent (m) | 244 m | 207 m |
| Climbing density (m/km) | 24.4 m/km | 20.7 m/km |
| Longest climb length (m) | 1,520 m | 840 m |
| Longest climb gain (m) | 108 m | 85 m |
| Longest climb average grade | 7.1% | 10.1% |
| Total descent (m) | 241 m | 208 m |
| Net elevation (m) | 2 m | -0 m |
| Max absolute grade | 18.1% | 22.0% |
| Start elevation (m) | 41 m | -0 m |
| Finish elevation (m) | 43 m | -0 m |
| Value | 84/100 | Unavailable |
| Scenic score | 77/100 | 87/100 ✓ |
| Conditions | 62/100 | 78/100 ✓ |
| Entry fee (GBP) | £32 | Unavailable |
| Lowest modelled true cost (GBP) | £162 | Unavailable |
GAP factor (% slower than flat)
- Portland Coastal Marathon 10K
- 4.8% Favoured
Uphill share
Steep-up share
Downhill share
Total ascent (m)
Climbing density (m/km)
- Two Tunnels Railway Races 10K
- 24.4 m/km
- Portland Coastal Marathon 10K
- 20.7 m/km
Longest climb length (m)
Longest climb gain (m)
Longest climb average grade
Total descent (m)
Net elevation (m)
Max absolute grade
Start elevation (m)
Finish elevation (m)
Value
- Portland Coastal Marathon 10K
- Unavailable
Scenic score
- Portland Coastal Marathon 10K
- 87/100 Favoured
Conditions
- Portland Coastal Marathon 10K
- 78/100 Favoured
Entry fee (GBP)
- Portland Coastal Marathon 10K
- Unavailable
Lowest modelled true cost (GBP)
- Portland Coastal Marathon 10K
- Unavailable
Only metrics available for at least one side are shown. A ✓ marks the better value for each metric (higher-is-better aware). Scores are out of 100 when available. Ascent, climbing density, max absolute grade and median finish describe course or field context and are not marked as better or worse.
Race facts that change the decision
| Fact | Two Tunnels Railway Races 10K | Portland Coastal Marathon 10K |
|---|---|---|
| Schedule | Exact race date not confirmed. Event weekend starts 2026-08-16 (legacy event-level date). | Exact race date not confirmed. Event weekend starts 2027-02-14 (legacy event-level date). |
| Location | Bath, South West | Portland, South West |
| Actual distance | 10 km | 10 km |
| raceindex.org mapped route held | Held | Held |
| raceindex.org elevation profile held | Held | Held |
| Course type | Unavailable | Laps |
| Surface | Unavailable | Coastal trail on the South West Coast Path (exposed limestone peninsula terrain). |
| Elevation character | Flat | Unavailable |
| Terrain | Road, Trail | Trail |
| Scenery | Parkland, Countryside, Riverside, City, Historic, Forest | Island, Coastal, Waterfront, City, Historic |
| Atmosphere | Scenic Tour, Community | Scenic Tour, Wilderness |
| Total ascent | 244 m | 207 m |
| Climbing density | 24.4 m/km | 20.7 m/km |
| Total descent | 241 m | 208 m |
| Net elevation | 2 m | -0 m |
| Max absolute grade | 18.1% | 22.0% |
| Flat grade share | 39.0% | 39.6% |
| GAP factor | 5.8% | 4.8% |
| Entry model | Open | Open |
| Entry fee | £32 | Unavailable |
| Lowest modelled true cost | £162 | Unavailable |
| Cost model origin | National Average | Unavailable |
| Measured course | Yes | No |
Schedule
- Two Tunnels Railway Races 10K
Exact race date not confirmed. Event weekend starts 2026-08-16 (legacy event-level date).
- Portland Coastal Marathon 10K
Exact race date not confirmed. Event weekend starts 2027-02-14 (legacy event-level date).
Location
- Two Tunnels Railway Races 10K
- Bath, South West
- Portland Coastal Marathon 10K
- Portland, South West
Actual distance
- Two Tunnels Railway Races 10K
- 10 km
- Portland Coastal Marathon 10K
- 10 km
raceindex.org mapped route held
- Two Tunnels Railway Races 10K
- Held
- Portland Coastal Marathon 10K
- Held
raceindex.org elevation profile held
- Two Tunnels Railway Races 10K
- Held
- Portland Coastal Marathon 10K
- Held
Course type
- Two Tunnels Railway Races 10K
- Unavailable
- Portland Coastal Marathon 10K
- Laps
Surface
- Two Tunnels Railway Races 10K
- Unavailable
- Portland Coastal Marathon 10K
- Coastal trail on the South West Coast Path (exposed limestone peninsula terrain).
Elevation character
- Two Tunnels Railway Races 10K
- Flat
- Portland Coastal Marathon 10K
- Unavailable
Terrain
- Two Tunnels Railway Races 10K
- Road, Trail
- Portland Coastal Marathon 10K
- Trail
Scenery
- Two Tunnels Railway Races 10K
- Parkland, Countryside, Riverside, City, Historic, Forest
- Portland Coastal Marathon 10K
- Island, Coastal, Waterfront, City, Historic
Atmosphere
- Two Tunnels Railway Races 10K
- Scenic Tour, Community
- Portland Coastal Marathon 10K
- Scenic Tour, Wilderness
Total ascent
- Two Tunnels Railway Races 10K
- 244 m
- Portland Coastal Marathon 10K
- 207 m
Climbing density
- Two Tunnels Railway Races 10K
- 24.4 m/km
- Portland Coastal Marathon 10K
- 20.7 m/km
Total descent
- Two Tunnels Railway Races 10K
- 241 m
- Portland Coastal Marathon 10K
- 208 m
Net elevation
- Two Tunnels Railway Races 10K
- 2 m
- Portland Coastal Marathon 10K
- -0 m
Max absolute grade
- Two Tunnels Railway Races 10K
- 18.1%
- Portland Coastal Marathon 10K
- 22.0%
Flat grade share
- Two Tunnels Railway Races 10K
- 39.0%
- Portland Coastal Marathon 10K
- 39.6%
GAP factor
- Two Tunnels Railway Races 10K
- 5.8%
- Portland Coastal Marathon 10K
- 4.8%
Entry model
- Two Tunnels Railway Races 10K
- Open
- Portland Coastal Marathon 10K
- Open
Entry fee
- Two Tunnels Railway Races 10K
- £32
- Portland Coastal Marathon 10K
- Unavailable
Lowest modelled true cost
- Two Tunnels Railway Races 10K
- £162
- Portland Coastal Marathon 10K
- Unavailable
Cost model origin
- Two Tunnels Railway Races 10K
- National Average
- Portland Coastal Marathon 10K
- Unavailable
Measured course
- Two Tunnels Railway Races 10K
- Yes
- Portland Coastal Marathon 10K
- No
Facts are shown only when they exist in the sourced race record; Not held means no sourced value is held for that race.
Common questions
Which is flatter, Two Tunnels Railway Races 10K or Portland Coastal Marathon 10K?
Portland Coastal Marathon 10K has the lower GAP factor, making it the flatter course on our route model and more favourable on gradient alone.