Contact between different metals raises a galvanic-corrosion problem, prompting discussion of anodes and active protection. The likely condition of a locomotive that has spent years in freshwater remains uncertain. Temperature layers can affect how much oxygen reaches the wreck, so an object below a low-oxygen layer could survive better than expected. Raising it into more oxygenated water could then accelerate corrosion. Preservation during recovery therefore depends on the artifact's condition and the environment through which it must pass.
Notable Point · 3:16:38-3:17:49
Why lake layers and corrosion matter during salvage
The locomotive discussion turns to galvanic corrosion and whether crossing a lake's thermal layers could expose an artifact to more oxygen.