Great Train Raid took place. The "Raid" was taking place the next day, symbolically recreating Stonewall Jackson's feat of moving a significant number of railroad cars from Martinsburg to Strasburg over the Valley Pike. There were no tracks between those points in 1861 and Jackson wanted to move the equipment for use by the Confederate army.
The locomotive shown here is a carefully-constructed replica built to 90% of original size by Strasburg craftsmen.
A Civil War Trails marker in Strasburg tells the story:
In the summer of 1861, Confederate Gen. Thomas J. “Stonewall” Jackson’s forces captured large quantities of Baltimore and Ohio Railroad rolling stock near Harper’s Ferry, 40 miles north. To reach the Manassas Gap Railroad line in Strasburg, the equipment had to be pulled by horses and mules up the Valley Turnpike from Martinsburg. Fourteen locomotives and almost a hundred cars were brought here and then used throughout the Confederacy.