Swung at the spike and missed
However, Alexander Toponce's first hand account written about 1919 in his autobiography states that:
"When they came to drive the last spike. Governor Stanford, president of the Central Pacific, took the sledge and the first time he struck he missed the spike and hit the rail.
What a howl went up! Irish, Chinese, Mexicans, and everybody yelled with delight. Everybody slapped everybody else on the back and yelled 'He missed it. Yee.' The engineers blew the whistles and rang their bells. Then Stanford tried it again and tapped the spike and the telegraph operators had fixed their instruments so that the tap was reported in all the offices, east and west, and set bells to tapping in hundreds of towns and cities. W. N. Shilling was one of the telegraph operators.
Then Vice President T. C. Durant of the Union Pacific took up the sledge and he missed the spike the first time. Then everybody slapped everybody else again and yelled, 'He missed it, [too], yow!' "