CP Scarborough Harbor Branch Line - HO Scale

[Sumpter250]

Tetters, a conceptual question. How long do you figure the pier deck has been there? What I mean is, did it see steam loco service or all diesel? Steam locos would have dripped oil/grease outside of the rails, where the cylinders and motion were, while diesels tend to drip in a line near the middle of the track.

Steam era, and early diesel era rolling stock, (and early diesel locos), had "oiled journals", which leaked oil on the ties just outside the rails. It was that same oil that gave wheels a dark color, instead of a more red/orange rust, seen on modern rolling stock, and locos.
By the same token, the rails close to my home had ballast that slowly acquired a heavy layer of Taconite pellets, which darkened the area between the rails, and to some extent, outside the rails also. There was always some "leakage" from the older "bottom dump" hoppers, and drop bottom gondolas, so a heavy traffic in any "hoppered" product, could "color" the rails and ties. Up hill tracks got lots of sand, downhill tracks got lots of brake shoe dust.