December 8, 2008
Installing new TIRES and then quartering & burnishing the crank pins.
Installing tires onto a driver center is not a common task in this century. ASTA's 786 has all new tires for the drivers. It is important that each driver's outside diameter be exactly the same, that each crank pin be exactly the same distance from the center line of the axle and that the opposing crankpins on each axle be at exactly 90 degrees. The, each crank pin is burnished to increase the surface hardness and give it a good service life.
The machining process to assure the crankpins are in the precise location is called "quartering". There are only a few machines remaining in in the world capable of performing this machining operation with good accuracy. One set of those machines is located at the Tennessee Valley Railroad in Chattanooga, TN where the work is being done under the management of the Steam Operations Corporation