Our daughter lived at that time, in a mountainside subdivision bordered by deep ravines, and there was a trail down one of those ravines (there was a road down the other). The trail followed the route of an old narrow gauge railway that led to a brick factory in the village of Clayburn.
The entrance we followed to the walking trail goes right between two houses, and is easy to find.Once you get there, it's a smooth gently-sloping trail, often 10 feet wide. I could picture a small freight train going down the trail quite easily.
Here's a map of the Clayburn Creek Trail, winding down the ravine. You're never far from the houses, but they are far above you through the rainforest. The valuable clay deposits are uphill on Sumas Mountain to the east. 'Burn' is the Scottish term for a creek; you can see how it got its name.
And then of course, the going downhill stretch ends and you're faced with those stairs. They are very well built and quite attractive, but they go on forever! If memory serves I think I counted 365 steps!
The trail doesn't go this far, but originally it went to the tiny company village of Clayburn, of which the Clayburn General Store is the most obvious evidence. This was B.C.'s first company town, complete with houses for workers, a church, a school, the store and a doctor. Several of these are provincially-designated heritage buildings today. The bricks they made are found all over Vancouver, and were shipped worldwide. You can look up the details on Google.