Speed records were different in WW1

Explanation: For much of WW1, advances were incredibly slow - defensive techniques and technology had advanced to a point where even massive concentrations of firepower and manpower could only make small gains - troops having to contend with uneven terrain, heavy bombardment, shrapnel, mudsinks, chemical weapons, overlapping machinegun fields of fire, fortified trenches, barbed wire, landmines, etc etc etc etc.

The invention and mass-production of the tank (first the British MK1, then the more modern layout of the French Renault FT ) allowed comparatively massive breakthroughs - trenches? The tracks can drag the big beast right over them. Machineguns? You'd need a hell of a lucky shot. Barbed wire? Effortlessly crushed beneath. Enabling what seem like small advances was lightning speed compared to the ~2 years of sluggish stalemate that preceded tank warfare!

(for some bonus trivia, the American M2 .50 cal machine gun was originally made to hose down enemy tanks with armor-piercing ammunition, but the war ended before it came into service, and the next major war had much better armored tanks)