Tunnel Light Marathon: Pacing & Race-Day Strategy
A pitch-black tunnel start under the Cascades, then a relentless downhill rail-trail to a Boston qualifier.
- Where:
- North Bend, Washington
- When:
- Sunday, September 13, 2026
- Course:
- Steep net downhill · rail-trail
- Best run as:
- Even pace
Course & elevation
Tunnel Light begins inside the former Snoqualmie railroad tunnel, where headlamps light a flat, two-mile descent through the dark before you burst into daylight on the Palouse-to-Cascades rail-trail. From there the crushed-gravel grade falls steadily for the entire race, well over a thousand feet of net drop, making it one of the most reliable BQ-chasing courses anywhere, provided your quads can take the pounding.
- Start → Finish
- 2,550 → 500 ft
- Net
- −2,050 ft
- Total gain
- ≈ 267 ft
Key moments
- Mile 0–2Headlamp-lit descent through the cool, dark Snoqualmie Tunnel. Mind your footing on the gravel.
- Mile 3–20Steady, uninterrupted downhill on the shaded rail-trail; resist the urge to hammer and let gravity do the work.
- Mile 23–26.2The grade eases near the finish, and quad fatigue bites here, so keep turnover quick and light.
Pacing strategy
Run the descent with a short, quick, low-impact stride rather than braking or over-striding. Pounding the downhill early will blow your quads by mile 18. Even effort on this grade naturally banks a fast time, so stay smooth and patient.
Pacing by goal time
Checkpoint splits for four common goals at Tunnel Light Marathon. These are effort-even rather than pace-even: the paces shift with the course profile, so climbs are slower and descents faster by the amount the grade actually costs. For any other goal time, use the planner below.
| Checkpoint | Sub-3:00 | Sub-3:30 | Sub-4:00 | Sub-4:30 |
|---|---|---|---|---|
| Mile 3.1 | 20:436:54/mi | 24:108:03/mi | 27:379:12/mi | 31:0410:21/mi |
| Mile 6.2 | 41:216:52/mi | 48:148:01/mi | 55:089:09/mi | 1:02:0110:18/mi |
| Mile 9.3 | 1:01:516:50/mi | 1:12:107:58/mi | 1:22:289:07/mi | 1:32:4710:15/mi |
| Mile 12.4 | 1:22:256:52/mi | 1:36:098:01/mi | 1:49:539:09/mi | 2:03:3710:18/mi |
| Mile 15.5 | 1:43:076:54/mi | 2:00:198:03/mi | 2:17:309:12/mi | 2:34:4110:21/mi |
| Mile 18.6 | 2:03:466:52/mi | 2:24:248:01/mi | 2:45:019:09/mi | 3:05:3910:18/mi |
| Mile 21.7 | 2:24:206:50/mi | 2:48:247:59/mi | 3:12:279:07/mi | 3:36:3110:15/mi |
| Mile 24.9 | 2:44:506:50/mi | 3:12:197:58/mi | 3:39:479:07/mi | 4:07:1610:15/mi |
| Finish | 2:58:306:50/mi | 3:28:157:58/mi | 3:58:009:07/mi | 4:27:4510:15/mi |
Grade adjustment is a model, not a promise. It assumes even effort and ignores wind, heat, and how well your legs handle sustained descent — which on a steep course is often the deciding factor.
Plan your mile splits
Enter your goal time to get a mile-by-mile pacing band for Tunnel Light Marathon. The even pace option is pre-selected to suit this course.
| Mile | Pace | Elapsed |
|---|---|---|
| 1 | 9:09/mi | 9:09 |
| 2 | 9:09/mi | 18:18 |
| 3 | 9:09/mi | 27:28 |
| 4 | 9:09/mi | 36:37 |
| 5 | 9:09/mi | 45:46 |
| 6 | 9:09/mi | 54:55 |
| 7 | 9:09/mi | 1:04:05 |
| 8 | 9:09/mi | 1:13:14 |
| 9 | 9:09/mi | 1:22:23 |
| 10 | 9:09/mi | 1:31:32 |
| 11 | 9:09/mi | 1:40:41 |
| 12 | 9:09/mi | 1:49:51 |
| 13 | 9:09/mi | 1:59:00 |
| 14 | 9:09/mi | 2:08:09 |
| 15 | 9:09/mi | 2:17:18 |
| 16 | 9:09/mi | 2:26:28 |
| 17 | 9:09/mi | 2:35:37 |
| 18 | 9:09/mi | 2:44:46 |
| 19 | 9:09/mi | 2:53:55 |
| 20 | 9:09/mi | 3:03:05 |
| 21 | 9:09/mi | 3:12:14 |
| 22 | 9:09/mi | 3:21:23 |
| 23 | 9:09/mi | 3:30:32 |
| 24 | 9:09/mi | 3:39:41 |
| 25 | 9:09/mi | 3:48:51 |
| 26 | 9:09/mi | 3:58:00 |
| 26.22 | 9:09/mi | 4:00:00 |
Fueling & hydration
Aid stations are spaced along the rural rail-trail (roughly every 2–3 miles) with water and sports drink; carry your own gels and a flask, since the remote course offers fewer stops than a city race. The cool, easy downhill rhythm makes it tempting to skip fuel, so keep a disciplined gel schedule.
Weather
Mid-September in the Cascade foothills is crisp and often damp at the early start (40s–50s°F), with the tunnel noticeably cold. Once you’re moving, racing temperatures are ideal.
Is Tunnel Light Marathon a good Boston qualifier?
It can be, but with an asterisk. The course drops 2,050 ft net, which puts it in the band where the B.A.A. adds 5:00 to your submitted time for 2027. That does not disqualify the race — it means you need to run 5 minutes faster here than the standard alone suggests.
A drop this size is fast and punishing at once. Sustained descent loads the quads eccentrically, and runners who have not trained for it tend to lose more in the last 10K than the profile gave them in the first. If you target this race, train downhill specifically.
This drop is our estimate rather than a figure from the course's certificate. If it sits near a threshold, confirm with the organizer.
Dial in your pacing & fueling
New to how training builds toward a race like this? Start with Anatomy of a Running Plan, find your zones with the pace calculator, and plan race-day nutrition with the fueling calculator.
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