The Spiral Tunnels open and the Big Hill is retired
After three years' work, two looped tunnels bored into the valley walls at Kicking Horse Pass — one under Cathedral Mountain, one through Mount Ogden — lengthen the line enough to bring the ruling grade down from about 4.5 per cent to 2.2. The Big Hill had been worked for a quarter of a century with runaway spurs and helper engines. The tunnels are the moment a railway pays, retrospectively, for the survey it declined to do in 1884.
Historical — it happened, and the record is settled.
Subjects
- Canadian Pacific transcontinental main line · route · Canada · not located
- Ruling gradient · physical criterion · not located
Evidence
Partly verified — Core facts are sourced; some optional detail is deliberately absent.
Spiral Tunnels — Yoho National Park
Supports the Big Hill's original grade of about 4.4–4.5 per cent over Kicking Horse Pass and its reduction to 2.2 per cent by the Spiral Tunnels, built 1907–1909. V55 verification basis: the Parks Canada page was returned in search but not fetched; the grade figures and the 1 September 1909 opening were carried in accompanying Canadian rail-history summaries and differ between sources on 4.4 versus 4.5 per cent.
Parks Canada · Partly verified
https://parks.canada.ca/pn-np/bc/yoho/culture/kickinghorse/visit/spirale-spiral
Recorded on Canadian Pacific transcontinental main line
- The last spike is driven at Craigellachie
- The Spiral Tunnels open and the Big Hill is retired
- The Severomuysky Tunnel opens under the BAM's worst obstacle
Related
Related because they share a subject in the Atlas — never because the text looks similar.