Quartering as we know is an experience often preceded by hanging and drawing.
But not always.
James May has been Reassembling again and tonight he showed us how he went about reassembling a Hornby 00 scale model steam locomotive, specifically the Flying Scotsman. It took him more than seven hours and in the course of this he explained about quartering as it applies to both model and full size locos
A steam loco is driven, as one would expect of a piston engined vehicle, by pistons and con rods. The driving wheels on one side are driven by one piston and those on the other side by another. If it should so happen that both pistons are at the same or opposite ends of their travel at the same time, the loco either won’t start or may do so in the opposite direction to that intended. To avoid this inconvenience, the wheels on one side are exactly 90deg ahead of the other so you never get each piston at what we’d nowadays call BDC or TDC at the same time. In principle any angle that’s not 0 or 180 would work, in practice you only get smooth running with exactly 90.
So there you have it. Quartering, explained slowly by Captain Slow.