Every schoolboy (at least of my generation) knows the answer.  The Gresley A4 Pacific 4468, “Mallard”, of course. 126mph in 1938.

Quite right.  But what is less commonly known is how tenuous is its claim to the title. 

Two years earlier, Germany’s Borsig DRG Series 005, Locomotive 02, attained 124.5mph – clearly second best.

Until you consider, that is, that the Mallard record was attained as a top speed on a downhill stretch south of Grantham, whereas the 02’s speed was the average over a measured distance.  More remarkably still, it achieved this hauling 197 tons of freight.

Enlightened opinion is that measured under similar conditions the German engine would have been the faster.

But there was never a subsequent challenge to the new record.  Perhaps the Third Reich was too busy planning that year’s annexation of Czechoslovakia and the fun of Kristallnacht, or the later invasion of Poland.

But no matter.  Tough shits, Fritz.

You snooze, you lose.