Forney locomotive

Placing the fuel and water over the truck rather than the driving wheels meant the locos had a constant adhesive weight, something other forms of tank locomotive did not.

Their short runs meant the limited fuel and water capacity was not a problem, making the Forney ideal.

However, their noise, smoke and tendency to drop ash and cinders (particularly from overhead tracks) made them unpopular.

Further developments included the introduction of locomotives with a leading pony truck, giving a 2-4-4 wheel arrangement.

Because the bogie was articulated, the reach rod and reversing lever were positioned above the main frame earning the locomotives the nickname "sewing machines.