Working the grade in the dead of winter is a miserable experience, but the infrastructure doesn't stop just because the temperature drops below freezing. Operating a tamping rammer machine in sub-zero conditions requires a completely different approach to both the dirt and the machine itself. Let's start with the machine. A commercial 4-stroke engine relies on oil splashing inside the crankcase to lubricate the moving parts. In the summer, standard 10W-30 oil flows like water. At -10°C [approx. 14°F], that same oil turns to molasses. If I just rip the recoil starter on a freezing morning, the engine will run dry for the first critical seconds, scoring the cylinder. In winter, I always transition my fleet to a winter-weight synthetic oil, and we let the machines idle for at least five minutes before engaging the clutch.
Furthermore, you have to consider the polyurethane corrugated bellows—the boot that protects the spring cylinder. In freezing weather, that heavy plastic becomes rigid and brittle. Hitting full throttle on a frozen boot can cause it to shatter, immediately exposing the oil bath to the elements. I train my guys to "warm up" the boot by running the machine at a very low idle, allowing the ambient heat from the engine block to soften the polyurethane before we drop it into the trench. Finally, you have to read the dirt. Frozen soil contains ice lenses. If you try to compact frozen clumps of clay, you are just breaking ice, not compacting dirt. When spring comes and that ice melts, your trench will instantly collapse. Winter compaction requires importing dry, unfrozen fill or using ground heaters before the jumping jack ever touches the dirt.
