The buildings were obstacles. In Skykomish, Washington, cleaning up railroad pollution meant temporarily moving entire structures because petroleum had spread beyond the rail yard into soil and groundwater beneath the town itself. The apparent excess of relocating buildings was, in practice, a way to reach contamination without sacrificing the buildings above it.
The trouble lay underground. Railroad fueling and maintenance operations had released petroleum that seeped into the subsurface, where groundwater movement helped carry contamination beyond its original sources. Oil does not simply disappear when surface operations stop: some remains trapped between soil particles, while some collects near the water table as light nonaqueous-phase liquid. Excavation offered a direct way to remove contaminated material, but foundations and occupied structures blocked access to portions of it. Merely treating exposed ground would have left pollution beneath those structures, allowing the remaining petroleum to continue affecting groundwater and complicating the cleanup.
Preservation required a detour. Under the cleanup overseen by Washington's Department of Ecology, BNSF Railway temporarily relocated affected buildings so crews could excavate beneath their footprints, remove polluted soil and replace it with clean material. Hydraulic jacks and supporting beams allowed structures to be lifted and moved rather than demolished. Utilities and foundations also required work before buildings could return. This was not relocation for redevelopment; it was access for environmental remediation, with the town's existing fabric kept intact where feasible. The houses could resume their places only after the ground beneath them had ceased to hold the railroad's residue.
