Named for the nearby Yellow Jacket Mine, the tunnel seen here was the 4th of 7 tunnels that dotted the original Virginia City line. It is 465 ft. long and back in the day, it was originally lined with wooden timbers. That didn't turn out to be such a great idea back when all of the locomotives in the V&T stable burned cord wood. Sparks from the hard-working 4-4-0s and 2-6-0s frequently set the tunnel bracing on fire. After one particularly bad fire in 1872, the railroad's engineers learned their lessons and they began to fireproof these tunnels with zinc and other types of sheet metal. When this particular tunnel was reopened for the new V&T in 1987, all of the internal bracing was done with welded steel. They no longer worry about fires on this line, but the exhaust fumes from the oil-burning locomotives can still get a little intense in there as the train struggles up the grade that averages 2.1% to Virginia City.