Flat grade share
- Portland Coastal Marathon 10K
- 39.6% Favoured
Portland Coastal Marathon 10K vs Two Tunnels Railway Races 10K
A data-led head-to-head using sourced race facts and available derived figures under one published methodology.
Data current as ofPortland Coastal Marathon 10K or Two Tunnels Railway Races 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
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%
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%
| Metric | Portland Coastal Marathon 10K | Two Tunnels Railway Races 10K |
|---|---|---|
| Flat grade share | 39.6% ✓ | 39.0% |
| GAP factor (% slower than flat) | 4.8% ✓ | 5.8% |
| Uphill share | 31.2% | 31.0% |
| Steep-up share | 11.5% | 16.4% |
| Downhill share | 29.2% | 30.0% |
| Total ascent (m) | 207 m | 244 m |
| Climbing density (m/km) | 20.7 m/km | 24.4 m/km |
| Longest climb length (m) | 840 m | 1,520 m |
| Longest climb gain (m) | 85 m | 108 m |
| Longest climb average grade | 10.1% | 7.1% |
| Total descent (m) | 208 m | 241 m |
| Net elevation (m) | -0 m | 2 m |
| Max absolute grade | 22.0% | 18.1% |
| Start elevation (m) | -0 m | 41 m |
| Finish elevation (m) | -0 m | 43 m |
| Value | Unavailable | 84/100 |
| Scenic score | 87/100 ✓ | 77/100 |
| Conditions | 78/100 ✓ | 62/100 |
| Entry fee (GBP) | Unavailable | £32 |
| Lowest modelled true cost (GBP) | Unavailable | £162 |
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)
- Portland Coastal Marathon 10K
- 20.7 m/km
- Two Tunnels Railway Races 10K
- 24.4 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 | Portland Coastal Marathon 10K | Two Tunnels Railway Races 10K |
|---|---|---|
| Schedule | Exact race date not confirmed. Event weekend starts 2027-02-14 (legacy event-level date). | Exact race date not confirmed. Event weekend starts 2026-08-16 (legacy event-level date). |
| Location | Portland, South West | Bath, South West |
| Actual distance | 10 km | 10 km |
| raceindex.org mapped route held | Held | Held |
| raceindex.org elevation profile held | Held | Held |
| Course type | Laps | Unavailable |
| Surface | Coastal trail on the South West Coast Path (exposed limestone peninsula terrain). | Unavailable |
| Elevation character | Unavailable | Flat |
| Terrain | Trail | Road, Trail |
| Scenery | Island, Coastal, Waterfront, City, Historic | Parkland, Countryside, Riverside, City, Historic, Forest |
| Atmosphere | Scenic Tour, Wilderness | Scenic Tour, Community |
| Total ascent | 207 m | 244 m |
| Climbing density | 20.7 m/km | 24.4 m/km |
| Total descent | 208 m | 241 m |
| Net elevation | -0 m | 2 m |
| Max absolute grade | 22.0% | 18.1% |
| Flat grade share | 39.6% | 39.0% |
| GAP factor | 4.8% | 5.8% |
| Entry model | Open | Open |
| Entry fee | Unavailable | £32 |
| Lowest modelled true cost | Unavailable | £162 |
| Cost model origin | Unavailable | National Average |
| Measured course | No | Yes |
Schedule
- Portland Coastal Marathon 10K
Exact race date not confirmed. Event weekend starts 2027-02-14 (legacy event-level date).
- Two Tunnels Railway Races 10K
Exact race date not confirmed. Event weekend starts 2026-08-16 (legacy event-level date).
Location
- Portland Coastal Marathon 10K
- Portland, South West
- Two Tunnels Railway Races 10K
- Bath, South West
Actual distance
- Portland Coastal Marathon 10K
- 10 km
- Two Tunnels Railway Races 10K
- 10 km
raceindex.org mapped route held
- Portland Coastal Marathon 10K
- Held
- Two Tunnels Railway Races 10K
- Held
raceindex.org elevation profile held
- Portland Coastal Marathon 10K
- Held
- Two Tunnels Railway Races 10K
- Held
Course type
- Portland Coastal Marathon 10K
- Laps
- Two Tunnels Railway Races 10K
- Unavailable
Surface
- Portland Coastal Marathon 10K
- Coastal trail on the South West Coast Path (exposed limestone peninsula terrain).
- Two Tunnels Railway Races 10K
- Unavailable
Elevation character
- Portland Coastal Marathon 10K
- Unavailable
- Two Tunnels Railway Races 10K
- Flat
Terrain
- Portland Coastal Marathon 10K
- Trail
- Two Tunnels Railway Races 10K
- Road, Trail
Scenery
- Portland Coastal Marathon 10K
- Island, Coastal, Waterfront, City, Historic
- Two Tunnels Railway Races 10K
- Parkland, Countryside, Riverside, City, Historic, Forest
Atmosphere
- Portland Coastal Marathon 10K
- Scenic Tour, Wilderness
- Two Tunnels Railway Races 10K
- Scenic Tour, Community
Total ascent
- Portland Coastal Marathon 10K
- 207 m
- Two Tunnels Railway Races 10K
- 244 m
Climbing density
- Portland Coastal Marathon 10K
- 20.7 m/km
- Two Tunnels Railway Races 10K
- 24.4 m/km
Total descent
- Portland Coastal Marathon 10K
- 208 m
- Two Tunnels Railway Races 10K
- 241 m
Net elevation
- Portland Coastal Marathon 10K
- -0 m
- Two Tunnels Railway Races 10K
- 2 m
Max absolute grade
- Portland Coastal Marathon 10K
- 22.0%
- Two Tunnels Railway Races 10K
- 18.1%
Flat grade share
- Portland Coastal Marathon 10K
- 39.6%
- Two Tunnels Railway Races 10K
- 39.0%
GAP factor
- Portland Coastal Marathon 10K
- 4.8%
- Two Tunnels Railway Races 10K
- 5.8%
Entry model
- Portland Coastal Marathon 10K
- Open
- Two Tunnels Railway Races 10K
- Open
Entry fee
- Portland Coastal Marathon 10K
- Unavailable
- Two Tunnels Railway Races 10K
- £32
Lowest modelled true cost
- Portland Coastal Marathon 10K
- Unavailable
- Two Tunnels Railway Races 10K
- £162
Cost model origin
- Portland Coastal Marathon 10K
- Unavailable
- Two Tunnels Railway Races 10K
- National Average
Measured course
- Portland Coastal Marathon 10K
- No
- Two Tunnels Railway Races 10K
- Yes
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, Portland Coastal Marathon 10K or Two Tunnels Railway Races 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.