4-8-4+4-8-4 classes of 4-8-4+4-8-4 steam locomotives across the globe, all of which were constructed by Beyer, Peacock and Company, the owners of the Garratt patent. The predecessor 4-8-2+2-8-4 Double Mountain was probably the optimal Garratt wheel arrangement, with the four-wheeled leading bogies and the two-wheeled trailing trucks on each engine unit ensuring stability at speed and with sixteen coupled wheels for traction. More coupled wheels would inhibit the locomotive on tight curves, while the only advantage of more non-coupled wheels, such as on the Double Northern, was to reduce the axle loading. The second Double Northern locomotive class were the AD60
Minim (unit) Minim (unit) The minim (abbreviated min, , , or ) is a unit of volume in both the imperial and US customary systems of measurement. Specifically it is of a fluidram or of a fluid ounce. In the Pharmacopoeia, it is also noted that the minim was originally created by Mr Timothy Lane, F.R.S., as parts per wine gallon. The minim was introduced in the 1809 edition of "The Pharmacopœia of the Royal College of Physicians of London" as a replacement for the drop, which had previously been the smallest unit of the apothecaries' system. It was observed that the